



Network Working Group                                  J. Preuß Mattsson
Internet-Draft                                               G. Selander
Updates: 6698 (if approved)                                  Ericsson AB
Intended status: Standards Track                                 S. Raza
Expires: 12 November 2026                          University of Glasgow
                                                              J. Höglund
                                                                 RISE AB
                                                              M. Furuhed
                                                               IN Groupe
                                                                 L. Liao
                                                                     NIO
                                                             11 May 2026


          CBOR Encoded X.509 Certificates (C509 Certificates)
                  draft-ietf-cose-cbor-encoded-cert-19

Abstract

   This document specifies a CBOR encoding of X.509 certificates.  The
   resulting certificates are called C509 certificates.  The CBOR
   encoding supports a large subset of RFC 5280 and common certificate
   profiles, and it is extensible.

   Two types of C509 certificates are defined.  One type is an
   invertible CBOR re-encoding of DER-encoded X.509 certificates with
   the signature field copied from the DER encoding.  The other type is
   identical except that the signature is computed over the CBOR
   encoding instead of the DER encoding, thereby avoiding the use of
   ASN.1.  Both types of certificates have the same semantics as X.509
   while providing comparable size reduction.

   This document also specifies CBOR-encoded data structures for
   certification requests and certification request templates, new COSE
   headers, as well as a TLS certificate type and a file format for
   C509.  This document updates RFC 6698 by extending the TLSA selectors
   registry to include C509 certificates.

About This Document

   This note is to be removed before publishing as an RFC.

   Status information for this document may be found at
   https://datatracker.ietf.org/doc/draft-ietf-cose-cbor-encoded-cert/.







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   Discussion of this document takes place on the CBOR Object Signing
   and Encryption Working Group mailing list (mailto:cose@ietf.org),
   which is archived at https://mailarchive.ietf.org/arch/browse/cose/.
   Subscribe at https://www.ietf.org/mailman/listinfo/cose/.

   Source for this draft and an issue tracker can be found at
   https://github.com/cose-wg/CBOR-certificates.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at https://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on 12 November 2026.

Copyright Notice

   Copyright (c) 2026 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents (https://trustee.ietf.org/
   license-info) in effect on the date of publication of this document.
   Please review these documents carefully, as they describe your rights
   and restrictions with respect to this document.  Code Components
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   described in Section 4.e of the Trust Legal Provisions and are
   provided without warranty as described in the Revised BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   4
   2.  Notational Conventions  . . . . . . . . . . . . . . . . . . .   6
   3.  C509 Certificate  . . . . . . . . . . . . . . . . . . . . . .   6
     3.1.  Message Fields  . . . . . . . . . . . . . . . . . . . . .   7
     3.2.  Encoding of subjectPublicKey and issuerSignatureValue . .  13
     3.3.  Encoding of Extensions  . . . . . . . . . . . . . . . . .  13
     3.4.  C509 COSE Header Parameters . . . . . . . . . . . . . . .  20



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     3.5.  C509 COSE Header Algorithm Parameters . . . . . . . . . .  21
     3.6.  Private Key Structures  . . . . . . . . . . . . . . . . .  22
     3.7.  Deterministic Encoding  . . . . . . . . . . . . . . . . .  23
     3.8.  C509 Name in TLS and DTLS . . . . . . . . . . . . . . . .  24
   4.  C509 Certification Request  . . . . . . . . . . . . . . . . .  24
     4.1.  Certification Request Types . . . . . . . . . . . . . . .  25
     4.2.  Subject Signature Algorithm . . . . . . . . . . . . . . .  26
     4.3.  Certification Request Attributes  . . . . . . . . . . . .  27
     4.4.  Certification Request Template  . . . . . . . . . . . . .  27
   5.  C509 Processing and Certificate Issuance  . . . . . . . . . .  29
   6.  Operational Considerations  . . . . . . . . . . . . . . . . .  30
     6.1.  Legacy Considerations . . . . . . . . . . . . . . . . . .  30
     6.2.  Expected Certificate Sizes  . . . . . . . . . . . . . . .  31
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .  32
   8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  33
     8.1.  Designated Expert Guidance  . . . . . . . . . . . . . . .  33
     8.2.  C509 Certificate Types Registry . . . . . . . . . . . . .  34
     8.3.  C509 Certification Request Types Registry . . . . . . . .  34
     8.4.  C509 Private Key Types Registry . . . . . . . . . . . . .  35
     8.5.  C509 Certification Request Templates Types Registry . . .  35
     8.6.  C509 RDN Attributes Registry  . . . . . . . . . . . . . .  36
     8.7.  C509 CR Attributes Registry . . . . . . . . . . . . . . .  40
     8.8.  C509 Extensions Registry  . . . . . . . . . . . . . . . .  41
     8.9.  C509 Certificate Policies Registry  . . . . . . . . . . .  45
     8.10. C509 Policies Qualifiers Registry . . . . . . . . . . . .  49
     8.11. C509 Information Access Registry  . . . . . . . . . . . .  49
     8.12. C509 Extended Key Usages Registry . . . . . . . . . . . .  51
     8.13. C509 General Names Registry . . . . . . . . . . . . . . .  53
     8.14. C509 Signature Algorithms Registry  . . . . . . . . . . .  55
     8.15. C509 Public Key Algorithms Registry . . . . . . . . . . .  59
     8.16. COSE Header Parameters Registry . . . . . . . . . . . . .  62
     8.17. COSE Header Algorithm Parameters Registry . . . . . . . .  62
     8.18. Media Type Application Registry . . . . . . . . . . . . .  62
     8.19. CoAP Content-Formats Registry . . . . . . . . . . . . . .  68
     8.20. TLS Certificate Types Registry  . . . . . . . . . . . . .  70
     8.21. TLSA Selectors Registry . . . . . . . . . . . . . . . . .  70
     8.22. EDHOC Authentication Credential Types Registry  . . . . .  71
     8.23. Relative Distinguished Name Attribute . . . . . . . . . .  71
   9.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  71
     9.1.  Normative References  . . . . . . . . . . . . . . . . . .  71
     9.2.  Informative References  . . . . . . . . . . . . . . . . .  75
   Appendix A.  C509 Certificate Examples  . . . . . . . . . . . . .  79
     A.1.  Example: RFC 7925 profiled X.509 Certificate  . . . . . .  79
     A.2.  Example: IEEE 802.1AR profiled X.509 Certificate  . . . .  84
     A.3.  Example: CAB Baseline ECDSA HTTPS X.509 Certificate . . .  88
     A.4.  Example: CAB Baseline RSA HTTPS X.509 Certificate . . . .  90
     A.5.  Example: Certificate with Extensions IPAddrBlocks and
           IPAddrBlocksV2  . . . . . . . . . . . . . . . . . . . . .  93



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   Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . .  97
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  97

1.  Introduction

   One of the challenges with deploying a Public Key Infrastructure
   (PKI) for the Internet of Things (IoT) is the size and parsing of
   X.509 public key certificates [RFC5280], since those are not
   optimized for constrained environments [RFC7228].  Large certificate
   chains are also problematic in non-constrained protocols such as EAP-
   TLS [RFC9190] [RFC9191] where authenticators typically drop an EAP
   session after only 40–50 round-trips, QUIC [RFC9000] where the
   latency increases significantly unless the server sends less than
   three times as many bytes as received prior to validating the client
   address, and Resource Public Key Infrastructure (RPKI) [RFC6487]
   where a single certificate can be very large.  More compact
   certificate representations are, therefore, desirable in many use
   cases.

   X.509 certificates are defined using Abstract Syntax Notation One
   (ASN.1) and encoded using the Distinguished Encoding Rules (DER)
   [X.690].  This document specifies an alternative encoding of X.509
   certificates using the Concise Binary Object Representation (CBOR)
   [RFC8949], initially proposed in [X.509-IoT].  The use of a more
   compact encoding reduces certificate size, which has known
   performance benefits in terms of decreased communication overhead,
   power consumption, latency, and storage requirements.  The re-
   encoding of X.509 is called C509, and the resulting certificates are
   termed C509 certificates.  C509 is not a general CBOR encoding for
   ASN.1 data structures.

   CBOR is a data format designed for small code size and small message
   size in systems with very limited memory, processor power, and
   instruction sets.  CBOR builds on the JSON data model but extends it
   by, for example, encoding binary data directly without base64
   conversion.  In addition to the binary CBOR encoding, CBOR also has a
   diagnostic notation that is human-readable and editable, which
   simplifies development and debugging.  The Concise Data Definition
   Language (CDDL) [RFC8610] provides a way to express structures for
   protocol messages and APIs that use CBOR.  [RFC8610] also extends the
   diagnostic notation.  For a complete specification and examples, see
   [RFC8949], [RFC8610], and [RFC8742].  A tool for becoming familiar
   with CBOR, available at the time of publication, is the CBOR
   playground [CborMe].

   The C509 encoding supports a large subset of [RFC5280] and all
   certificates profiled for [RFC7925], IEEE 802.1AR (DevID)
   [IEEE-802.1AR], CAB Baseline [CAB-TLS], [CAB-Code], RPKI [RFC6487],



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   Wi-SUN [Wi-SUN], and eUICC [GSMA-eUICC].  C509 is designed for small
   code size and compact encoding of certificates in constrained
   environments including certificates profiled specifically for IoT
   deployments, but can be applied to certificate-based authentication
   in general, for example, using TLS [RFC8446], QUIC [RFC9000], DTLS
   [RFC9147], COSE [RFC9052] and EDHOC [RFC9528].  This document does
   not specify a certificate profile.

   At the time of publication, there are several C509 implementations
   targeting, for example, in-vehicle and vehicle-to-cloud
   communication, Uncrewed Aircraft Systems (UAS), and Global Navigation
   Satellite System (GNSS) deployments.  When used to re-encode DER-
   encoded X.509 certificates, the CBOR encoding can reduce the size of
   [RFC7925]-profiled certificates by more than 50%; see Appendix A.

   C509 is designed to be extensible to additional X.509 features, for
   example, support for new algorithms, including new Post-Quantum (PQ)
   algorithms, which can be registered in the IANA registry as they are
   specified; see Section 8.14.

   This document defines two types of C509 using the same CBOR encoding
   and differing only in what is being signed:

   1.  An invertible CBOR re-encoding of DER-encoded X.509 certificates
       [RFC5280], which can be reversed to obtain the original DER-
       encoded X.509 certificate, which can be verified using legacy
       certificate software.  Due to the widespread deployment of X.509,
       it is necessary to allow backward compatibility.

   2.  Natively signed C509 certificates, where the signature is
       calculated over the CBOR encoding instead of the DER encoding.
       This removes the need for ASN.1 and DER parsing and the
       associated complexity, but such certificates are not backward
       compatible with implementations requiring DER-encoded X.509.
       Natively signed C509 certificates can be used in devices that are
       only required to authenticate to servers compatible with natively
       signed C509 certificates.  This is not a major restriction in
       many IoT deployments in which the parties that issue and verify
       certificates are part of a restricted ecosystem.

   This document also specifies C509 Certification Requests; see
   Section 4.  It further specifies COSE headers for use with C509
   certificates in COSE; see Section 8.16; a TLS certificate type for
   use with C509 certificates in TLS and QUIC, with or without
   additional TLS certificate compression; see Section 8.20; and a C509
   file format.  By extending the TLSA selectors registry to include
   C509 certificates, this document updates [RFC6698].




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2.  Notational Conventions

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in
   BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
   capitals, as shown here.

   This specification makes use of the terminology in [RFC2986],
   [RFC5280], [RFC7228], [RFC8610], and [RFC8949].  When referring to
   CBOR, this specification always refers to Deterministically Encoded
   CBOR as specified in Sections 4.2.1 and 4.2.2 of [RFC8949].

3.  C509 Certificate

   This section specifies the content and encoding of C509 certificates,
   with the objective of producing a compact representation that
   supports a large part of [RFC5280] and all of [RFC7925],
   [IEEE-802.1AR], RPKI [RFC6487], GSMA eUICC [GSMA-eUICC], and CAB
   Baseline [CAB-TLS] [CAB-Code].

   In the CBOR encoding, static fields are elided, elliptic curve points
   and time values are compressed, OIDs are replaced with short integers
   or complemented with CBOR OID encoding [RFC9090], and redundant
   encoding is removed.  Combining these techniques significantly
   reduces certificate size, which is not achievable with general-
   purpose compression algorithms; see Figure 5.

   A C509 certificate can be either a CBOR re-encoding of a DER-encoded
   X.509 certificate, in which case the signature is calculated on the
   DER-encoded ASN.1 data in the X.509 certificate, or a natively signed
   C509 certificate, in which case the signature is calculated directly
   on the CBOR-encoded data.  In both cases, the certificate content
   adheres to the restrictions given in [RFC5280].  The re-encoding is
   known to work with DER-encoded certificates, but it might also work
   with other canonical encodings.  The re-encoding does not work for
   BER-encoded certificates.

   In the encoding described below, the elements in arrays are always
   encoded in the same order as elements of the corresponding SEQUENCE
   or SET in the DER encoding.










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3.1.  Message Fields

   This section describes the X.509 fields and their CBOR encodings and
   uses them in the definition of C509 certificates; see Figure 1.
   While many of [RFC5280] encodings are supported, there are a few
   instances marked "not supported" for which no alternative is provided
   and, therefore, no C509 encoding can be generated.

   The following Concise Data Definition Language (CDDL) defines the
   CBOR array C509Certificate and the CBOR Sequence [RFC8742]
   TBSCertificate.  The member names therefore have documentary value
   only.  Applications that do not require a CBOR item MAY represent
   C509 certificates using the CBOR sequence ~C509Certificate (unwrapped
   C509Certificate).  Examples are given in the appendices; see, for
   example, Appendix A.1.




































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   C509Certificate = [
      TBSCertificate,
      issuerSignatureValue : any,
   ]

   ; The elements of the following group are used in a CBOR Sequence:
   TBSCertificate = (
      c509CertificateType: int,
      certificateSerialNumber: CertificateSerialNumber,
      issuerSignatureAlgorithm: AlgorithmIdentifier,
      issuer: Name / null,
      validityNotBefore: ~time,
      validityNotAfter: ~time / null,
      subject: Name,
      subjectPublicKeyAlgorithm: AlgorithmIdentifier,
      subjectPublicKey: Defined,
      extensions: Extensions,
   )

   CertificateSerialNumber = ~biguint

   Name = [ * RDNAttribute ] / SpecialText

   RDNAttribute = (
       ( attributeType: int, attributeValue: SpecialText ) //
       ( attributeType: ~oid, attributeValue: bytes )
   )

   AlgorithmIdentifier = int / ~oid /
                       [ algorithm: ~oid, parameters: bytes ]

   Extensions = [ * Extension ] / int

   Extension = (
       ( extensionID: int, extensionValue: Defined ) //
       ( extensionID: ~oid, extensionValue: bytes / [ bytes ] )
   )

   SpecialText = text / bytes / tag

   Defined = any .ne undefined

   tag = #6

                    Figure 1: CDDL for C509Certificate.

   C509 certificates are defined in terms of DER-encoded X.509
   certificates [RFC5280] as detailed in the following subsections.



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3.1.1.  version

   The 'version' field is encoded in the 'c509CertificateType' CBOR int.
   The field 'c509CertificateType' also indicates the type of the C509
   certificate.  Two types are defined in this document: natively signed
   C509 certificates, following X.509 v3 (c509CertificateType = 2); and
   CBOR re-encoded X.509 v3 DER certificate (c509CertificateType = 3),
   see Section 8.2.  The number of elements in TBSCertificate is fixed
   and determined by the type.  Additional types may be added in the
   future.

3.1.2.  certificateSerialNumber

   The 'certificateSerialNumber' INTEGER value field is encoded as the
   unwrapped CBOR unsigned bignum (~biguint) 'CertificateSerialNumber'.
   Any leading 0x00 byte (to indicate that the number is not negative)
   is therefore omitted.

3.1.3.  signature

   The 'signature' field, containing the signature algorithm including
   parameters, is encoded as a CBOR int (see Section 8.14) or as an
   array with an unwrapped CBOR OID tag [RFC9090] optionally followed by
   the parameters encoded as a CBOR byte string.

3.1.4.  issuer

   In the general case, the sequence of 'RDNAttribute' is encoded as a
   CBOR array consisting of RDNAttribute elements.
   RelativeDistinguishedName with more than one AttributeTypeAndValue is
   not supported.  Each RDNAttribute is CBOR-encoded as (type, value),
   either as an (int, SpecialText) pair or as a (~oid, bytes) tuple.



















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   In the former case, the absolute value of the int encodes the
   attribute type (see Figure 10) and the sign is used to represent the
   character string type in the X.509 certificate; positive for
   utf8String, negative for printableString.  Attribute values which are
   always of type IA5String are unambiguously represented using a non-
   negative int.  Examples include emailAddress and domainComponent (see
   [RFC5280]).  In CBOR, all text strings are UTF-8 encoded and in
   natively signed C509 certificates all CBOR ints SHALL be non-
   negative.  Text strings SHALL still adhere to any [RFC5280]
   restrictions.  The value of the attributes serialNumber and
   countryName SHALL contain only characters from the 74-character ASCII
   subset permitted by PrintableString.  Additionally, the value of the
   countryName attribute SHALL have length 2.  CBOR encoding is allowed
   for IA5String (if this is the only allowed type, e.g., emailAddress),
   printableString and utf8String, whereas the string types
   teletexString, universalString, and bmpString are not supported.

   The text strings are further optimized as follows:

   *  If the text string has an even length of at least 2 and contains
      only the symbols '0'-'9' or 'a'-'f', it is encoded as a CBOR byte
      string.

   *  If the text string contains an EUI-64 of the form "HH-HH-HH-HH-HH-
      HH-HH-HH" where each 'H' is one of the symbols '0'-'9' or 'A'-'F',
      it is encoded as a CBOR tagged MAC address using the CBOR tag 48,
      see Section 2.4 of [RFC9542].  If of the form "HH-HH-HH-FF-FE-HH-
      HH-HH", it is encoded as a 48-bit MAC address, otherwise as a
      64-bit MAC address.  See example in Appendix A.1.

   *  Otherwise, it is encoded as a CBOR text string.

   The final encoding of the attribute value may therefore be text,
   bytes, or tag, i.e., SpecialText.  If Name contains a single 'common
   name' attribute with attributeType = +1, it is for compactness
   encoded as just the SpecialText containing the single attribute
   value.

   In natively signed C509 certificates, bytes and tag 48 do not
   correspond to any predefined text string encoding and may also be
   used for other attribute types.

   If the 'issuer' field is identical to the 'subject' field, e.g., in
   case of self-signed certificates, then the 'issuer' field MUST be
   encoded as the CBOR simple value null (0xf6).






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3.1.5.  validity

   The 'notBefore' and 'notAfter' fields are encoded as unwrapped CBOR
   epoch-based date/time (~time) where the tag content is an unsigned
   integer.  In POSIX time [POSIX], leap seconds are ignored, with a
   leap second having the same POSIX time as the second before it.
   Compression of X.509 certificates with the time 23:59:60 UTC is
   therefore not supported.  Note that RFC 5280 mandates encoding of
   dates through the year 2049 as UTCTime, and later dates as
   GeneralizedTime.  The value "99991231235959Z" (no expiration date) is
   encoded as the CBOR simple value null.

3.1.6.  subject

   The 'subject' field is encoded exactly like issuer, except that the
   CBOR simple value null is not a valid value.

3.1.7.  subjectPublicKeyInfo

   The 'AlgorithmIdentifier' field including parameters is encoded as
   the CBOR int 'subjectPublicKeyAlgorithm' (see Section 8.15) or as an
   array with an unwrapped CBOR OID tag [RFC9090] optionally followed by
   the parameters encoded as a CBOR byte string.

   In general, the 'subjectPublicKey' BIT STRING value field is encoded
   as a CBOR byte string, but may be encoded as a CBOR item of any type
   except undefined (see Section 4.4).  This specification assumes the
   BIT STRING has zero unused bits, and the unused bits byte is omitted.
   For rsaEncryption and id-ecPublicKey, the encoding of
   subjectPublicKey is further optimized as described in Section 3.2.

3.1.8.  issuerUniqueID

   Not supported.

3.1.9.  subjectUniqueID

   Not supported.

3.1.10.  extensions

   The 'extensions' field is encoded either as a CBOR array or as a CBOR
   int.  An omitted 'extensions' field is encoded as an empty CBOR
   array.

   Each 'extensionID' in the CBOR array is encoded either as a CBOR int
   (see Section 8.8) or as an unwrapped CBOR OID tag [RFC9090].




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   *  If 'extensionID' is encoded as a CBOR int, it is followed by a
      CBOR item of any type except undefined (see Section 4.4), and the
      sign of the int is used to encode if the extension is critical:
      Critical extensions are encoded with a negative sign and non-
      critical extensions are encoded with a positive sign.  If the CBOR
      array contains exactly two ints and the absolute value of the
      first int is 2 (corresponding to keyUsage, see Section 3.3), the
      CBOR array is omitted and the 'extensions' field is encoded as a
      single CBOR int with the absolute value of the second int and the
      sign of the first int.

   *  If extensionID is encoded as an unwrapped CBOR OID tag, it is
      followed by the DER-encoded extnValue encoded in the following
      way:

      -  if the extension is non-critical, the extnValue OCTET STRING
         value field is encoded as a CBOR byte string;

      -  if the extension is critical, the extnValue OCTET STRING value
         field is encoded as a CBOR byte string and further wrapped in a
         CBOR array consisting of only this element.

   The processing of critical and non-critical extensions is specified
   in Section 4.2 of [RFC5280].

   The currently defined extension values for which there is CBOR int
   encoded 'extensionID' are specified in Section 3.3.  The extensions
   mandated to be supported by [RFC7925] and [IEEE-802.1AR] are given
   special treatment.

   More details about extensions in Section 3.3.

3.1.11.  signatureAlgorithm

   The 'signatureAlgorithm' field is always the same as the 'signature'
   field and therefore omitted from the CBOR encoding.

3.1.12.  signatureValue

   In general, the 'signatureValue' BIT STRING value field is encoded as
   the CBOR byte string issuerSignatureValue.  This specification
   assumes that the BIT STRING has zero unused bits, and the unused bits
   byte is omitted.  For natively signed C509 certificates, the
   signatureValue is calculated over the CBOR sequence TBSCertificate.
   For ECDSA, the encoding of issuerSignatureValue is further optimized
   as described in Section 3.2.





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3.2.  Encoding of subjectPublicKey and issuerSignatureValue

3.2.1.  Encoding of subjectPublicKey

   For RSA public keys (rsaEncryption), the SEQUENCE and INTEGER type
   and length fields are omitted, and the two INTEGER value fields
   (modulus, exponent) are encoded as an array of two unwrapped CBOR
   unsigned bignum (~biguint), i.e., [ modulus : ~biguint, exponent :
   ~biguint ].  If the exponent is 65537, the array and the exponent are
   omitted and subjectPublicKey consists of only the modulus encoded as
   an unwrapped CBOR unsigned bignum (~biguint).

   For elliptic curve public keys in Weierstrass form (id-ecPublicKey),
   keys may be point-compressed as defined in Section 2.3.3 of [SECG].
   Native C509 certificates with Weierstrass form keys use the octets
   0x02, 0x03, and 0x04 as defined in [SECG].  If a DER-encoded
   certificate with an uncompressed public key of type id-ecPublicKey is
   CBOR-encoded with point compression, then the octet 0xfe is used
   instead of 0x02 to represent an even y-coordinate, and the octet 0xfd
   is used instead of 0x03 to represent an odd y-coordinate.

3.2.2.  Encoding of issuerSignatureValue

   ECDSA signatures are encoded in the same way as in Section 2.1 of
   [RFC9053].  For example, for P-256, the number of bytes for each
   integer is 32.  The resulting byte string is encoded as a CBOR byte
   string.

3.3.  Encoding of Extensions

   The 'extensions' field is encoded as specified in Section 3.1.10 with
   further details provided in this section.

   For some extensions, the CBOR int encoded extensionID is only
   supported for commonly used values of the extension.  In case of
   extension values for which the CBOR int encoded extensionID is not
   supported, the extension MUST be encoded using the unwrapped CBOR OID
   tag encoded extensionID.

   A note on extensionID naming: in existing OID databases, the same OID
   can be found in versions with and without an 'id-pe' or 'id-ce'
   prefix.  We have excluded the prefix for the commonly used extensions
   defined in [RFC5280] and included them for extensions defined
   elsewhere.

   CBOR encoding of the following extension values is fully supported:





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   *  Subject Key Identifier (subjectKeyIdentifier).  In natively signed
      certificates, KeyIdentifier can, for example, be composed of the
      leftmost 160 bits of the SHA-256 hash of the CBOR encoded
      subjectPublicKey.  Other methods of generating unique numbers can
      be used.  The extensionValue is encoded as follows:

      KeyIdentifier = bytes
      SubjectKeyIdentifier = KeyIdentifier

   *  Key Usage (keyUsage).  The 'KeyUsage' BIT STRING is interpreted as
      an unsigned integer in network byte order and encoded as a CBOR
      int.  See Section 3.1.10 for special encoding in case keyUsage is
      the only extension present.

      KeyUsage = uint

   *  Policy Mappings (policyMappings). extensionValue is encoded as
      follows:

      PolicyMappings = [
        + (issuerDomainPolicy: int/~oid, subjectDomainPolicy: int/~oid)
      ]

   *  Basic Constraints (basicConstraints).  If 'cA' = false then
      extensionValue = -2, if 'cA' = true and 'pathLenConstraint' is not
      present then extensionValue = -1, and if 'cA' = true and
      'pathLenConstraint' is present then extensionValue =
      pathLenConstraint.

      BasicConstraints = int

   *  Policy Constraints (policyConstraints). extensionValue is encoded
      as follows:

      PolicyConstraints = [
        requireExplicitPolicy: uint / null,
        inhibitPolicyMapping: uint / null,
      ]

   *  Extended Key Usage (extKeyUsage). extensionValue is encoded as an
      array of CBOR ints (see Section 8.12), or unwrapped CBOR OID tags
      [RFC9090], where each int or OID encodes a key usage purpose.  If
      the array contains a single KeyPurposeId, the array is omitted.

      KeyPurposeId = int / ~oid
      ExtKeyUsageSyntax = [ 2* KeyPurposeId ] / KeyPurposeId





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   *  Inhibit anyPolicy (inhibitAnyPolicy). extensionValue is encoded as
      follows:

      InhibitAnyPolicy = uint

   *  IPAddrBlocks (id-pe-ipAddrBlocks).  The X.509 extension
      IPAddrBlocks is specified in [RFC3779].  The ASN.1 BIT STRING
      value of IPAddress is converted to a byte sequence defined as:

      unusedBits || value

      where unusedBits is a single octet indicating the number of unused
      bits in the final octet of the BIT STRING, and value is the
      sequence of octets containing the BIT STRING value.  This byte
      sequence preserves the exact information contained in the ASN.1
      BIT STRING.

      For each IPAddressFamily, the representation is selected as
      follows:

      -  If inherit is present, null SHALL be used.

      -  Otherwise, if the byte sequence of any IPAddress (including
         addressPrefix, and the min and max fields of addressRange)
         exceeds 8 octets in length, the IPAddressChoice representation
         SHALL be used.

      -  Otherwise, the IntIPAddressChoice representation SHALL be used.

      For IntIPAddressChoice, IntAddressPrefix and the min and max
      values of IntAddressRange SHALL be encoded as big-endian integers
      representing the following byte sequence:

      (unusedBits + 1) || value

      The first byte is encoded as (unusedBits + 1) instead of
      unusedBits in order to guarantee a non-zero value.  With the
      exception of the first IPAddress, each subsequent IPAddress SHALL
      be encoded as a CBOR integer representing the difference from the
      previous IPAddress.

      As specified in [RFC3779], the IPAddressFamily element contains an
      Address Family Identifier (AFI) and, optionally, a Subsequent
      Address Family Identifier (SAFI).  AFIs and SAFIs are defined in
      [IANA-AFI] and [IANA-SAFI], respectively.  The limitations
      specified in [RFC3779] apply here as well.





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      IntAddressPrefix = int
      IntAddressRange  = [ min: int, max: int ]
      IntIPAddressOrRange = IntAddressPrefix / IntAddressRange
      IntIPAddressChoice  = [ + IntIPAddressOrRange ]

      AddressPrefix = bytes
      AddressRange  = [ min: bytes, max: bytes ]
      IPAddressOrRange = AddressPrefix / AddressRange
      IPAddressChoice  = [ + IPAddressOrRange ]

      IPAddressFamily = (AFI: uint, SAFI: uint / null,
                         IntIPAddressChoice / IPAddressChoice / null)
      IPAddrBlocks = [ + IPAddressFamily ]

   *  IPAddrBlocks v2 (id-pe-ipAddrBlocks-v2).  The X.509 extension
      IPAddrBlocks v2 is specified in [RFC8360].  The extension value is
      encoded exactly like in the extension "IPAddrBlocks".

   *  OCSP No Check (id-pkix-ocsp-nocheck).  The CBOR encoded
      extensionValue is the value null.

   *  TLS Features (id-pe-tlsfeature).  The extensionValue is encoded as
      an array of integers, where each integer represents a TLS
      extension.

      TLSFeatures = [* feature: uint]

   CBOR encoding of the following extension values are partly supported:

   *  Subject Alternative Name (subjectAltName).  If the subject
      alternative name only contains general names registered in
      Section 8.13 the extension value can be CBOR encoded.
      extensionValue is encoded as an array of (int, any) pairs where
      each pair encodes a general name (see Section 8.13).  If
      subjectAltName contains exactly one dNSName, the array and the int
      are omitted and extensionValue is the dNSName encoded as a CBOR
      text string.  In addition to the general names defined in
      [RFC5280], the otherName values with type-id id-on-
      hardwareModuleName, id-on-SmtpUTF8Mailbox and id-on-MACAddress
      have been given their own ints; such otherName values are encoded
      as follows:

      -  For id-on-hardwareModuleName, the value is a CBOR array [
         hwType: ~oid, hwSerialNum: bytes ] as specified in [RFC4108].

      -  For id-on-SmtpUTF8Mailbox, the value is a CBOR text as
         specified in [RFC9598].




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      -  For id-on-MACAddress, the value is a CBOR byte string
         containing 6 octets for EUI-48 and 8 octets for EUI-64 as
         specified in [I-D.ietf-lamps-macaddress-on].

      GeneralName = ( GeneralNameType : int, GeneralNameValue : any )
      GeneralNames = [ + GeneralName ]
      SubjectAltName = GeneralNames / text

   *  Issuer Alternative Name (issuerAltName). extensionValue is encoded
      exactly like subjectAltName.

      IssuerAltName  = GeneralNames / text

   *  CRL Distribution Points (cRLDistributionPoints).  If all
      DistributionPoint elements contain the distributionPoint with
      fullName choice of uniformResourceIdentifier, optional reasons,
      and optional cRLIssuer with one directoryName, the extension value
      can be CBOR-encoded.  The 'reasons' BIT STRING is interpreted as
      an unsigned integer in network byte order and encoded as a CBOR
      uint.  If the CRLDistributionPoints consists of only one
      DistributionPointName, which in turn has only the fullName field
      of type CBOR text, it is encoded as CBOR text; otherwise it is
      encoded as a CBOR array.

      DistributionPointName = [
        fullName:  [ 2 * text ] / text,
        reasons:   uint / null,
        cRLIssuer: Name / null,
      ]

      CRLDistributionPoints = [ + DistributionPointName ] / text

   *  Freshest CRL (freshestCRL). extensionValue is encoded exactly like
      cRLDistributionPoints.

      FreshestCRL = CRLDistributionPoints

   *  Authority Information Access (authorityInfoAccess).  If all the
      GeneralNames in authorityInfoAccess are of type
      uniformResourceIdentifier, the extension value can be CBOR-
      encoded.  Each accessMethod is encoded as a CBOR int (see
      Section 8.11) or an unwrapped CBOR OID tag [RFC9090].  The
      uniformResourceIdentifiers are encoded as CBOR text strings.

      AccessDescription = ( accessMethod: int / ~oid , uri: text )
      AuthorityInfoAccessSyntax = [ + AccessDescription ]





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   *  Subject Information Access (subjectInfoAccess).  Encoded exactly
      like authorityInfoAccess.

      SubjectInfoAccessSyntax = AuthorityInfoAccessSyntax

   *  Authority Key Identifier (authorityKeyIdentifier).  If the
      authority key identifier contains all of keyIdentifier,
      authorityCertIssuer, and authorityCertSerialNumber, or if only
      keyIdentifier is present, the extension value can be CBOR-encoded.
      If all three are present, a CBOR array is used.  If only
      keyIdentifier is present, the array is omitted:

      KeyIdentifierArray = [
        keyIdentifier: KeyIdentifier,
        authorityCertIssuer: GeneralNames,
        authorityCertSerialNumber: CertificateSerialNumber,
      ]
      AuthorityKeyIdentifier = KeyIdentifierArray / KeyIdentifier

   *  Certificate Policies (certificatePolicies).  If noticeRef is not
      used and any explicitText values are encoded as UTF8String, the
      extension value can be CBOR-encoded.  OIDs registered in
      Section 8.9 are encoded as an int.  The policyQualifierId is
      encoded as a CBOR int (see Section 8.10) or an unwrapped CBOR OID
      tag [RFC9090].

      PolicyIdentifier = int / ~oid
      PolicyQualifierInfo = (
        policyQualifierId: int / ~oid,
        qualifier: text,
      )
      CertificatePolicies = [
        + ( PolicyIdentifier, [ * PolicyQualifierInfo ] )
      ]

   *  Name Constraints (nameConstraints).  If the name constraints only
      contain general names registered in Section 8.13, the extension
      value can be CBOR-encoded.  C509 uses the same additions and
      restrictions as defined in Section 2.2 of [RFC9549].  Note that
      the minimum and maximum fields are not used and are therefore
      omitted.  For IPv4 addresses, the iPAddress field MUST contain
      five octets, and for IPv6 addresses, the field MUST contain 17
      octets.  In both cases the last octet indicates the number of bits
      in the prefix.  As an example, the address block 192.0.2.0/24 is
      encoded as C0 00 02 00 18 instead of C0 00 02 00 FF FF FF 00 as in
      the DER encoding.





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      GeneralSubtrees = [ + GeneralName ]
      NameConstraints = [
        permittedSubtrees: GeneralSubtrees / null,
        excludedSubtrees: GeneralSubtrees / null,
      ]

   *  Subject Directory Attributes (subjectDirectoryAttributes).
      Encoded as attributes in issuer and subject with the difference
      that there can be more than one attributeValue.

      RDNAttributes = (
        ( attributeType: int, attributeValue: [ + SpecialText] ) //
        ( attributeType: ~oid, attributeValue: [+ bytes] )
      )
      SubjectDirectoryAttributes = [ + RDNAttributes ]

   *  AS Identifiers (id-pe-autonomousSysIds).  The X.509 extension AS
      Identifiers is specified in [RFC3779].  If 'rdi' is not present,
      the extension value can be CBOR-encoded.  Each ASId is encoded as
      a CBOR uint.  With the exception of the first ASId, each
      subsequent ASId is encoded as the difference from the previous
      ASId.

      ASIdOrRange = uint / [min:uint, max:uint]
      ASIdentifiers = [ + ASIdOrRange ] / null

   *  AS Identifiers v2 (id-pe-autonomousSysIds-v2).  The X.509
      extension AS Identifiers v2 is specified in [RFC8360].  The
      extension value is encoded exactly like in the extension "AS
      Identifiers".

3.3.1.  Example Encoding of Extensions

   The examples below use values from Section 8.8, Section 8.12, and
   Section 8.13:

   *  A critical basicConstraints ('cA' = true) without
      pathLenConstraint is encoded as the two CBOR ints -4, -1.

   *  A non-critical keyUsage with digitalSignature (0), nonRepudiation
      (1), keyEncipherment (2) and keyAgreement (4) asserted is encoded
      as the two CBOR ints 2, 23 (2^0 + 2^1 + 2^2 + 2^4 = 23).

   *  A non-critical extKeyUsage containing id-kp-codeSigning and id-kp-
      OCSPSigning is encoded as the CBOR int 8 followed by the CBOR
      array [ 3, 9 ].





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   *  A non-critical subjectAltName containing only the dNSName
      example.com is encoded as the CBOR int 3 followed by the CBOR text
      string "example.com".

   Thus, the extension field of a certificate containing all of the
   above extensions in the given order would be encoded as the CBOR
   array [ -4, -1, 2, 23, 8, [ 3, 9 ], 3, "example.com" ].

3.4.  C509 COSE Header Parameters

   The formatting and processing for c5b, c5c, c5t, and c5u, defined in
   Table 1 below, are similar to x5bag, x5chain, x5t, x5u defined in
   [RFC9360] except that the certificates are C509 instead of DER-
   encoded X.509 and use a COSE_C509 structure instead of COSE_X509.

   The COSE_C509 structure used in c5b, c5c, and c5u is defined as:

   COSE_C509 = C509CertData / [ 2* C509CertData ]
   C509CertData = bytes .cborseq C509Certificate

   C509CertData thus includes the unwrapped CBOR sequence,
   ~C509Certificate.  The byte string encoding includes the length of
   each certificate, which simplifies parsing.  See Appendix A.1.5 for
   an example.

   The COSE_C509 item has media type application/cose-c509-cert, see
   Section 8.18.1.  Different CoAP Content-Formats are defined depending
   on "usage" = "chain" or not, see Section 8.19.  Stored file formats
   are defined for the cases with/without ("usage" = "chain") with
   "magic numbers" TBD8/TBD6 using the reserved CBOR tag 55799 and the
   corresponding Content-Formats TBD15/TBD3, enveloped as described in
   Section 2.2 of [RFC9277].

   The value type of c5t is the COSE_CertHash structure defined in
   [RFC9360], which contains the hash value of the C509 certificate
   calculated over ~C509Certificate.  Thus, C509CertData contains all
   data necessary to calculate the thumbprint c5t.

   c5u provides an alternative way to identify an untrusted certificate
   chain by reference with a URI [RFC3986], encoded as a CBOR text
   string (media type application/cbor and CoAP Content-Format 60).  The
   referenced resource is a COSE_C509 item served with the application/
   cose-c509-cert media type ("usage" = "chain"), as described above.








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   As the contents of c5b, c5c, c5t, and c5u are untrusted input, the
   header parameters can be in either the protected or unprotected
   header bucket.  The trust mechanism MUST process any certificates in
   the c5b, c5c, and c5u parameters as untrusted input.  The presence of
   a self-signed certificate in the parameter MUST NOT cause the update
   of the set of trust anchors without appropriate authorization.

      +======+=======+===============+=============================+
      | Name | Label | Value Type    | Description                 |
      +======+=======+===============+=============================+
      |  c5b | 24    | COSE_C509     | An unordered bag of C509    |
      |      |       |               | certificates                |
      +------+-------+---------------+-----------------------------+
      |  c5c | 25    | COSE_C509     | An ordered chain of C509    |
      |      |       |               | certificates                |
      +------+-------+---------------+-----------------------------+
      |  c5t | 22    | COSE_CertHash | Hash of a ~C509Certificate  |
      +------+-------+---------------+-----------------------------+
      |  c5u | 23    | uri           | URI pointing to a COSE_C509 |
      |      |       |               | containing an ordered chain |
      |      |       |               | of certificates             |
      +------+-------+---------------+-----------------------------+

                   Table 1: C509 COSE Header Parameters

   Certificates can also be identified with a 'kid' header parameter by
   storing the 'kid' value and the associated bag or chain in a
   dictionary.

3.5.  C509 COSE Header Algorithm Parameters

   This section defines the COSE header parameters used for identifying
   or transporting the sender's key for static-static key agreement
   algorithms corresponding to Section 3 of [RFC9360], see Table 2.

   *  c5c-sender contains the chain of certificates starting with the
      sender's key exchange certificate.  The structure is the same as
      'c5c'.

   *  c5t-sender contains the hash value for the sender's key exchange
      certificate.  The structure is the same as 'c5t'.

   *  c5u-sender contains a URI for the sender's key exchange
      certificate.  The structure and processing are the same as 'c5u'.







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   +======+==========+=============+===============+==================+
   |  Name|Algorithm | Label       | Type          | Description      |
   +======+==========+=============+===============+==================+
   |  c5c-|ECDH-     | -30         | COSE_C509     | An ordered chain |
   |sender|SS+HKDF-  | (suggested) |               | of C509          |
   |      |256, ECDH-|             |               | certificates     |
   |      |SS+HKDF-  |             |               |                  |
   |      |512, ECDH-|             |               |                  |
   |      |SS+A128KW,|             |               |                  |
   |      |ECDH-     |             |               |                  |
   |      |SS+A192KW,|             |               |                  |
   |      |ECDH-     |             |               |                  |
   |      |SS+A256KW |             |               |                  |
   +------+----------+-------------+---------------+------------------+
   |  c5t-|ECDH-     | -31         | COSE_CertHash | Hash of a        |
   |sender|SS+HKDF-  | (suggested) |               | ~C509Certificate |
   |      |256, ECDH-|             |               |                  |
   |      |SS+HKDF-  |             |               |                  |
   |      |512, ECDH-|             |               |                  |
   |      |SS+A128KW,|             |               |                  |
   |      |ECDH-     |             |               |                  |
   |      |SS+A192KW,|             |               |                  |
   |      |ECDH-     |             |               |                  |
   |      |SS+A256KW |             |               |                  |
   +------+----------+-------------+---------------+------------------+
   |  c5u-|ECDH-     | -32         | uri           | URI pointing to  |
   |sender|SS+HKDF-  | (suggested) |               | a COSE_C509      |
   |      |256, ECDH-|             |               | containing an    |
   |      |SS+HKDF-  |             |               | ordered chain of |
   |      |512, ECDH-|             |               | certificates     |
   |      |SS+A128KW,|             |               |                  |
   |      |ECDH-     |             |               |                  |
   |      |SS+A192KW,|             |               |                  |
   |      |ECDH-     |             |               |                  |
   |      |SS+A256KW |             |               |                  |
   +------+----------+-------------+---------------+------------------+

                  Table 2: Static ECDH Algorithm Values

3.6.  Private Key Structures

   Certificate management also makes use of data structures including
   private keys; see, e.g., [RFC7468].  This section defines the
   following CBOR-encoded structures:







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   C509PrivateKey = [
      C509PrivateKeyType: int,
      subjectPrivateKeyAlgorithm: AlgorithmIdentifier,
      subjectPrivateKey: any,
   ]

   The field 'C509PrivateKeyType' indicates the type of the C509 private
   key.  Different types of C509 Private Key Structures can be defined,
   see Section 8.4.  Currently, two types are defined.  When
   C509PrivateKeyType = 0, the subjectPrivateKey is the CBOR byte string
   encoding of the PrivateKey OCTET STRING value field defined in
   [RFC5958].  When C509PrivateKeyType = 1, the subjectPrivateKey is a
   COSE_KEY structure containing a private key as defined in [RFC9052].
   Note that COSE_KEY might not be possible to use with all algorithms
   that have a C509 AlgorithmIdentifier defined.

   The C509PrivateKey item is served with the application/cose-
   c509-privkey media type, see Section 8.18.4, with corresponding CoAP
   Content-Format defined in Section 8.19.  A stored file format is
   defined with "magic number" TBD12 using the reserved CBOR tag 55799
   and the Content-Format TBD10, enveloped as described in Section 2.2
   of [RFC9277].

   C509PEM = [
      C509PrivateKey,
      COSE_C509 / null,
   ]

   The C509PEM item is served with the application/cose-c509-pem media
   type, see Section 8.18.5, with corresponding CoAP Content-Format
   defined in Section 8.19.  A stored file format is defined with "magic
   number" TBD13 using the reserved CBOR tag 55799 and the Content-
   Format TBD11, enveloped as described in Section 2.2 of [RFC9277].

3.7.  Deterministic Encoding

   In some use cases it is desirable to be able to specify a unique C509
   representation of a given X.509 certificate.

   Although this specification requires the use of Deterministically
   Encoded CBOR (see Section 2), it is still possible to represent
   certain X.509 certificate fields in different ways.  This is a
   consequence of the extensibility of the C509 format, in which new
   encodings can be defined, for example, to optimize extensions for
   which no special CBOR encoding has previously been defined.






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   Where both a specific and a generic CBOR encoding are supported, the
   specific CBOR encoding MUST be used.  For example, when a specific
   CBOR encoding of an extension is defined in Section 3.3 and the C509
   Extensions Registry, that specific encoding MUST be used.  In
   particular, when a specific otherName encoding is available,
   identified by a negative integer value in the C509 General Names
   Registry, it MUST be used.

   Native C509 certificates MUST use only specific CBOR-encoded fields.
   However, when decoding non-native C509 certificates, the decoder may
   need to support, for example, the (extensionID: ~oid, extensionValue:
   bytes / [bytes]) encoding of an extension for which an (extensionID:
   int, extensionValue: Defined) encoding exists.  One reason is that
   the certificate might have been issued before the specific CBOR
   extension was registered.

3.8.  C509 Name in TLS and DTLS

   In TLS and DTLS, the subject of a trusted authority may be sent to
   the peer to help it select the certificate chain, as in the
   CertificateAuthoritiesExtension in [RFC8446], in the
   certificate_authorities field of CertificateRequest in [RFC5246], or
   in the TrustedAuthorities in [RFC6066].  For such usage in TLS and
   DTLS, the C509 name is wrapped in a distinguished name [X.501] with
   exactly one RelativeDistinguishedName, which in turn contains exactly
   one AttributeTypeAndValue with the attribute C509Name.  The attribute
   value is the raw byte string of the encoded C509 Name as specified in
   Section 3.1.6.

   The attribute for C509 Name has the following structure:

   id-rdna-c509Name OBJECT IDENTIFIER ::= { 1 3 6 1 5 5 7 25 TBD30 }

   c509Name ATTRIBUTE ::= {
      WITH SYNTAX C509Name
      SINGLE VALUE TRUE
      ID id-rdna-c509Name }

   C509Name ::= OCTET STRING

4.  C509 Certification Request

   This section defines the format of a C509 Certification Request based
   on [RFC2986].  It reuses the encodings of C509 certificates defined
   in Section 3.  A Certification Request is commonly referred to as a
   Certificate Signing Request (CSR).





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   The CDDL for the C509 Certification Request is shown in Figure 2.
   The fields have the same encoding as the corresponding fields of the
   C509 Certificate, see Section 3.1.

   C509CertificationRequest = [
      TBSCertificationRequest,
      subjectSignatureValue: any,
   ]

   ; The elements of the following group are used in a CBOR Sequence:
   TBSCertificationRequest = (
      c509CertificationRequestType: int,
      subjectSignatureAlgorithm: AlgorithmIdentifier,
      subject: Name,
      subjectPublicKeyAlgorithm: AlgorithmIdentifier,
      subjectPublicKey: Defined,
      attributes: CRAttributes,
   )

   CRAttributes = [ * CRAttribute ]

   CRAttribute = (( attributeType: int, attributeValue: Defined ) //
                  ( attributeType: ~oid, attributeValue: bytes ))

                Figure 2: CDDL for C509CertificationRequest.

   After verifying subjectSignatureValue, the Certification Authority
   (CA) MAY transform the C509CertificationRequest into a [RFC2986]
   CertificationRequestInfo for compatibility with existing procedures
   and implementations.

   The media type of C509CertificationRequest is application/cose-
   c509-pkcs10, see Section 8.18.2, with corresponding CoAP Content-
   Format defined in Section 8.19.  The "magic number" TBD9 is defined
   using the reserved CBOR tag 55799 and the Content-Format TBD4,
   enveloped as described in Section 2.2 of [RFC9277].

4.1.  Certification Request Types

   Two types of C509 Certification Requests are defined.  Both use the
   same CBOR encoding and differ only in what is being signed; see
   Section 8.3.  A C509 Certification Request is either an invertible
   CBOR re-encoding of a DER-encoded certification request [RFC2986] or
   a natively signed request in which the signature is calculated over
   the CBOR encoding instead of the DER encoding.






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   *  c509CertificationRequestType = 2.  This type indicates that the
      C509 Certification Request is natively signed, i.e., that
      subjectSignatureValue contains the signature over the CBOR
      Sequence TBSCertificationRequest; see Figure 2.  This encoding
      removes the need for ASN.1 and DER parsing and for re-encoding by
      the requesting party.

   *  c509CertificationRequestType = 3.  This type indicates that the
      C509 Certification Request is a CBOR re-encoded [RFC2986]
      certification request, as defined in Section 4.  This encoding is
      backward compatible with legacy RFC 2986 certification requests
      and reduces transport overhead.

   The type of certificate issued in response to the request is
   determined by the application.  For C509, the default is
   c509CertificateType = c509CertificationRequestType.

   An implementation MAY only support certain values of
   c509CertificationRequestType.

4.2.  Subject Signature Algorithm

   subjectSignatureAlgorithm can be a signature algorithm or a non-
   signature proof-of-possession algorithm, for example, as defined in
   [RFC6955].  In the case of [RFC6955], the signature is replaced by a
   MAC and requires a public Diffie-Hellman key of the verifier to be
   distributed out of band.  Both signature algorithms and non-signature
   proof-of-possession algorithms are listed in the C509 Signature
   Algorithms Registry; see Section 8.14.  The non-signature proof-of-
   possession algorithms with SHA-2 and HMAC-SHA2 (see values 14-16 in
   Section 8.14) require a signature value with syntax DhSigStatic,
   defined as follows:

   DhSigStatic = MessageDigest / DhSigStaticType

   MessageDigest = bytes

   DhSigStaticType = [
     issuer: Name,
     certificateSerialNumber: CertificateSerialNumber,
     hashValue: MessageDigest,
   ]

   Note that a key agreement key pair may be used with a signature
   algorithm in a certification request, see Appendix A.1.3.






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4.3.  Certification Request Attributes

   The 'attributes' field specifies the attributes contained in a
   certification request.  The 'attributes' field with no
   GeneralAttribute SHALL be encoded as an empty CBOR array.

   The remainder of this section specifies CBOR-encoded attributes for
   Certification Requests.

4.3.1.  Extension Request

   The X.509 attribute "Extension Request" is defined in [RFC2985].  The
   'attributeValue' field has type Extensions as in Section 3.1.  An
   empty CBOR array indicates no extensions.

4.3.2.  Challenge Password

   The X.509 attribute "Challenge Password" is defined in [RFC2985].
   The 'attributeValue' field has type ChallengePassword.  A UTF8 String
   is encoded as CBOR text, and a Printable String is tagged with number
   121 (alternative 0 as defined in [IANA-CBOR-TAGS]).  All other string
   types are not supported.  For certification request type 2, only UTF8
   String is allowed.

   ChallengePassword = text / #6.121(text)

4.3.3.  Private Key Possession Statement

   The X.509 attribute "Statement of Possession of a Private Key" is
   defined in [RFC9883].  The 'attributeValue' field has type
   PrivateKeyPossessionStatement.

   PrivateKeyPossessionStatement = [
     issuer: Name,
     certificateSerialNumber: CertificateSerialNumber,
     cert: C509Certificate / null,
   ]

4.4.  Certification Request Template

   Enrollment over Secure Transport (EST, [RFC7030]) defines, and
   [RFC9908] clarifies, how an EST server can specify what it expects
   the EST client to include in a subsequent Certification Request.
   Alternatively to the unstructured mechanism specified in [RFC7030],
   Appendix B of [RFC8295] describes an approach using a Certification
   Request Template in response to a GET /csrattrs request by the EST
   client.  The EST server thus returns a Certification Request-like
   object with various fields filled out, and other fields waiting to be



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   filled in and a signature to be added by the EST client.

   The approach of [RFC8295] is also followed for C509.  The
   C509CertificationRequestTemplate is based on TBSCertificationRequest
   of the C509CertificationRequest, see Figure 2, but excludes the
   subjectSignatureValue field from the template since that needs no
   further specification.

   The C509 Certification Request Template is shown in Figure 3.

   C509CertificationRequestTemplate = [
      c509CertificationRequestTemplateType: int,
      c509CertificationRequestType: [+ int] / undefined,
      subjectSignatureAlgorithm: [+ AlgorithmIdentifier] / undefined,
      subject: NameTemplate / undefined,
      subjectPublicKeyAlgorithm: [+ AlgorithmIdentifier] / undefined,
      subjectPublicKey: undefined,
      extensionsRequest: ExtensionsTemplate / undefined,
   ]

   NameTemplate = [ * RDNAttributeTemplate ]

   RDNAttributeTemplate = (
       ( attributeType: uint, minOccurs: uint, maxOccurs: uint,
         attributeValue: SpecialText / undefined ) //
       ( attributeType: ~oid, minOccurs: uint, maxOccurs: uint,
         attributeValue: bytes / undefined )
   )

   ExtensionsTemplate = [ * ExtensionTemplate ]

   ExtensionTemplate = (
       ( extensionID: uint, optional: bool, extensionValue: any ) //
       ( extensionID: ~oid, optional: bool,
       extensionValue: bytes / undefined )
   )

            Figure 3: CDDL for C509CertificationRequestTemplate.

   Except as specified in this section, the fields have the same
   encoding as the corresponding fields of the TBSCertificationRequest,
   see Figure 2.  The specification of the template makes use of the
   CBOR simple value undefined (0xf7) to indicate fields to fill in.
   Consistent with this rule, note that the subjectPublicKey field
   always has the value undefined in the template.






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   Different types of Certification Request Templates can be defined
   (see Section 8.5), distinguished by the
   c509CertificationRequestTemplateType integer.  Each type may have its
   own CDDL structure.

   The presence of a Defined (non-undefined) value in a
   C509CertificationRequestTemplate indicates that the server expects
   the client to use that value in the certification request.  If
   multiple AlgorithmIdentifier or c509CertificationRequestType values
   are present, the server expects the client to select one of them for
   use in the Certification Request.  The presence of an undefined value
   indicates that the client is expected to provide an appropriate value
   for that field.  For example, if the server includes a subjectAltName
   with a GeneralNameType iPAddress and a GeneralNameValue empty byte
   string, this means that the client SHOULD fill in a corresponding
   GeneralNameValue.

   For RDNAttributeTemplate, the minOccurs and maxOccurs fields specify
   the minimal and maximal occurrences of attributes of the given
   attributeType; maximal shall not be less than minimal, and maximal
   shall be positive.  Negative attributeType is not allowed.

   For ExtensionTemplate, the field "optional" specifies whether an
   extension of the given extensionID is optional.  Negative extensionID
   is not allowed.

   The media type of C509CertificationRequestTemplate is application/
   cose-c509-crtemplate, see Section 8.18.3, with corresponding CoAP
   Content-Format defined in Section 8.19.  The "magic number" TBD18 is
   defined using the reserved CBOR tag 55799 and the Content-Format
   TBD19, enveloped as described in Section 2.2 of [RFC9277].

5.  C509 Processing and Certificate Issuance

   It is straightforward to integrate the C509 format into legacy X.509
   processing during certificate issuance.  C509 processing can be
   performed as an isolated function of the CA, or as a separate
   function trusted by the CA.

   The Certification Request format defined in Section 4 follows the
   PKCS#10 format to enable a direct mapping to the certification
   request information, see Section 4.1 of [RFC2986].  The CA can make
   use of a Certification Request Template defined in Section 4.4, for
   simplified configuration.







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   When a certification request is received, the CA, or function trusted
   by the CA, needs to perform some limited C509 processing and verify
   the proof-of-possession corresponding to the public key, before
   normal certificate generation can take place.

   In the reverse direction, in case c509CertificateType = 3 was
   requested, a separate C509 processing function can perform the
   conversion from a generated X.509 certificate to C509 as a bump-in-
   the-wire.  In case c509CertificateType = 2 was requested, the C509
   processing needs to be performed before signing the certificate, in
   which case a tighter integration with the CA may be needed.

6.  Operational Considerations

6.1.  Legacy Considerations

   C509 certificates can be deployed with legacy X.509 certificates and
   CA infrastructure.  An existing CA can continue to use its existing
   procedures and code for PKCS#10, and DER-encoded X.509 and only
   implement C509 as a thin processing layer on top.  When receiving a
   C509 Certification Request, the CA transforms it into a DER-encoded
   CertificationRequestInfo [RFC2986] and uses that with existing
   processes and code to produce an RFC 5280 DER-encoded X.509
   certificate.  The DER-encoded X.509 is then transformed into a C509
   certificate.  At any later point, the C509 certificate can be used to
   recreate the original X.509 data structure needed to verify the
   signature.

   For protocols like TLS/DTLS 1.2, where certificates are sent
   unencrypted, the actual encoding and compression can be done at
   different locations depending on the deployment setting.  For
   example, the mapping between C509 certificate and standard X.509
   certificate can take place in a 6LoWPAN border gateway, which allows
   the server side to stay unmodified.  This case gives the advantage of
   the low overhead of a C509 certificate over constrained wireless
   links.  The conversion to X.509 within a constrained IoT device will
   incur a computational overhead.  However, measured in energy, this is
   likely to be negligible compared to the reduced communication
   overhead.

   For the setting with constrained server and server-only
   authentication, the server only needs to be provisioned with the C509
   certificate and does not perform the conversion to X.509.  This
   option is viable when client authentication can be asserted by other
   means.






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   For protocols like IKEv2, TLS/DTLS 1.3, and EDHOC, where certificates
   are encrypted, the proposed encoding needs to be done fully end-to-
   end, through adding the encoding/decoding functionality to the
   server.

6.2.  Expected Certificate Sizes

   The CBOR encoding of the sample certificate chains given in
   Appendix A results in the numbers shown in Figures 4 and 5.
   COSE_X509 is defined in [RFC9360] and COSE_C509 is defined in
   Section 8.16.  After [RFC7925] profiling, most duplicated information
   has been removed, and the remaining text strings are minimal in size.
   Therefore, the further size reduction reached with general
   compression mechanisms such as Brotli [RFC7932] will be small, mainly
   corresponding to making the ASN.1 encoding more compact.  CBOR
   encoding can however significantly compress RFC 7925 profiled
   certificates.  In the examples with HTTPS certificate chains
   (www.ietf.org (ECDSA) and cabforum.org (RSA)) both C509 and Brotli
   perform well complementing each other.  C509 uses dedicated
   information to compress individual certificates, while Brotli can
   compress duplicate information in the entire chain.  Note that C509
   certificates of type 2 and 3 have the same size.  For Brotli, the
   Rust crate Brotli 3.3.0 was used with compression level 11 and window
   size 22.

   In the examples using FN-DSA and ML-DSA certificate chains, the
   largest portion of the certificate size consists of the public keys
   and signatures, which are essentially random.  As a result, both
   Brotli and C509 achieve only very limited size reduction.  However,
   C509 still performs slightly better.

    +----------------------------------------+-----------+-----------+
    | Description (number of certs)          | COSE_X509 | COSE_C509 |
    +----------------------------------------+-----------+-----------+
    | RFC 7925 profiled IoT Certificate (1)  |       319 |       142 |
    +----------------------------------------+-----------+-----------+
    | RPKI Certificate (1)                   |     20981 |     11523 |
    +----------------------------------------+-----------+-----------+
    | ECDSA HTTPS Certificate Chain (2)      |      1644 |      1012 |
    +----------------------------------------+-----------+-----------+
    | RSA HTTPS Certificate Chain (2)        |      2909 |      2240 |
    +----------------------------------------+-----------+-----------+
    | FN-DSA-512 HTTPS Certificate Chain (2) |      4417 |      3897 |
    +----------------------------------------+-----------+-----------+
    | ML-DSA-65 HTTPS Certificate Chain (2)  |     11863 |     11318 |
    +----------------------------------------+-----------+-----------+





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      Figure 4: Comparing Sizes of Certificate Chains in COSE.  Number
                  of bytes (length of certificate chain).

       +-----------------------+-------+---------+-------+--------+
       | Description           | X.509 | X.509 + | C509  | C509 + |
       | (number of certs)     |       | Brotli  |       | Brotli |
       +-----------------------+-------+---------+-------+--------+
       | RFC 7925 profiled     |   325 |     317 |  149  |    158 |
       | IoT Certificate (1)   |       |         |       |        |
       +-----------------------+-------+---------+-------+--------+
       | RPKI Certificate (1)  | 20987 |    9109 | 11529 |   7020 |
       +-----------------------+-------+---------+-------+--------+
       | ECDSA HTTPS           |  1651 |    1181 |  1019 |    930 |
       | Certificate Chain (2) |       |         |       |        |
       +-----------------------+-------+---------+-------+--------+
       | RSA HTTPS             |  2656 |    2195 |  2071 |   1913 |
       | Certificate Chain (2) |       |         |       |        |
       +-----------------------+-------+---------+-------+--------+
       | FN-DSA-512 HTTPS      |  4437 |    4026 |  3917 |   3776 |
       | Certificate Chain (2) |       |         |       |        |
       +-----------------------+-------+---------+-------+--------+
       | ML-DSA-65 HTTPS       | 11869 |   11420 | 11325 |  11148 |
       | Certificate Chain (2) |       |         |       |        |
       +-----------------------+-------+---------+-------+--------+

       Figure 5: Comparing Sizes of Certificate Chains with TLS 1.3.
       Number of bytes (length of certificate chain).  X.509 and C509
      are Certificate messages.  X.509 + Brotli and C509 + Brotli are
                      CompressedCertificate messages.

7.  Security Considerations

   The CBOR encoding of X.509 certificates does not change the security
   assumptions needed when deploying standard X.509 certificates.  The
   same security procedures applies as for X.509.  For example the same
   certificate path validation as defined in Section 6 of [RFC5280] MUST
   be performed on C509 certificates before they can be considered
   trusted.  The security considerations of [RFC5280] apply.

   The use of natively signed C509 certificates removes the need for
   ASN.1 encoding, which is a rich source of security vulnerabilities.

   Conversion between the certificate formats can be made in constant
   time to reduce risk of information leakage through side channels.







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   The mechanism in this document does not reveal any additional
   information compared to X.509.  Because of the difference in size, it
   will be possible to detect that this profile is used.  The gateway
   solution described in Section 6.1 requires unencrypted certificates
   which may violate identity protection and is not recommended.

   Any issues with decoding or parsing a C509 certificate should be
   handled exactly as how such errors would be handled for the
   corresponding X.509 certificate.  For example, a non-critical
   extension MAY be ignored if it is not recognized, see Section 4.2 of
   [RFC5280].

   As stated in Section 3.4, the contents of the COSE Header Parameters
   c5b, c5c, c5t, c5u is untrusted input that potentially may be
   verified using existing trust anchors or other trust establishment
   mechanism out of scope of this document.  Similar security
   considerations as x5bag, x5chain, x5t and x5u apply, see [RFC9360].
   Security considerations of the COSE protected and unprotected headers
   are discussed in [RFC9052].

   The specification makes no recommendations on the use of algorithms,
   paddings, or other security constructs applied in the encoding of a
   certificate.  In particular, an IANA registration does not imply a
   recommendation.  For example, some deprecated algorithms are assigned
   code points only for backward compatibility to enable CBOR encoding
   of existing certificates.

8.  IANA Considerations

   This document creates several new registries in the new registry
   group "CBOR Encoded X.509 (C509)".  For all items, the 'Reference'
   field points to this document.

   Editor's note: Add informative reference to the newly created IANA
   registries and updated existing registries.

8.1.  Designated Expert Guidance

   Reviewers are encouraged to get sufficient information for
   registration requests to ensure that the usage is not going to
   duplicate one that is already registered and that the point is likely
   to be used in deployments.  Experts should take into account the
   expected usage of entries when approving point assignment.  The
   length of the encoded value should be weighed against the number of
   code points left that encode to that size and how constrained the
   systems it will be used on are.  Values in the interval [-24, 23]
   have a 1-byte encoding, other values in the interval [-256, 255] have
   a 2-byte encoding, and the remaining values in the interval [-65536,



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   65535] have a 3-byte encoding.

   All assignments according to "IETF Review with Expert Review" are
   made on an "IETF Review" basis per Section 4.8 of [RFC8126] with
   "Expert Review" additionally required per Section 4.5 of [RFC8126].
   The procedure for early IANA allocation of "standards track code
   points" defined in [RFC7120] also applies.  When such a procedure is
   used, IANA will ask the designated expert(s) to approve the early
   allocation before registration.  In addition, working group chairs
   are encouraged to consult the expert(s) early during the process
   outlined in Section 3.1 of [RFC7120].

8.2.  C509 Certificate Types Registry

   IANA has created a new registry titled "C509 Certificate Types" under
   the registry group "CBOR Encoded X.509 (C509)".  The fields of the
   registry are Value, Description, and Reference, where Value is an
   integer, and the other columns are text strings.  It is mandatory to
   specify content in all columns.  For values in the interval [-24,
   23], the registration procedure is "IETF Review with Expert Review".
   For all other values, the registration procedure is "Expert Review".
   The initial contents of the registry are (see Section 3.1.1):

           +-------+-------------------------------------------+
           | Value | Description                               |
           +=======+===========================================+
           |     0 | Reserved                                  |
           +-------+-------------------------------------------+
           |     1 | Reserved                                  |
           +-------+-------------------------------------------+
           |     2 | Natively Signed C509 Certificate          |
           +-------+-------------------------------------------+
           |     3 | CBOR Re-encoded X.509 v3 Certificate      |
           +-------+-------------------------------------------+

                      Figure 6: C509 Certificate Types

8.3.  C509 Certification Request Types Registry

   IANA has created a new registry titled "C509 Certification Request
   Types" under the new registry group "CBOR Encoded X.509 (C509)".  The
   fields of the registry are Value, Description, and Reference, where
   Value is an integer, and the other columns are text strings.  All
   columns are mandatory.  For values in the interval [-24, 23] the
   registration procedure is "IETF Review with Expert Review".  For all
   other values the registration procedure is "Expert Review".  The
   initial contents of the registry are:




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   +-------+-----------------------------------------------------------+
   | Value | Description                                               |
   +=======+===========================================================+
   |     0 | Reserved                                                  |
   +-------+-----------------------------------------------------------+
   |     1 | Reserved                                                  |
   +-------+-----------------------------------------------------------+
   |     2 | Natively Signed C509 Certification Request.               |
   +-------+-----------------------------------------------------------+
   |     3 | CBOR re-encoding of RFC 2986 certification request.       |
   +-------+-----------------------------------------------------------+

                 Figure 7: C509 Certification Request Types

8.4.  C509 Private Key Types Registry

   IANA has created a new registry titled "C509 Private Key Types" in
   the new registry group "CBOR Encoded X.509 (C509)".  The fields of
   the registry are Value, Comments, subjectPrivateKey, and Reference,
   where Value is an integer, and the other columns are text strings.
   The subjectPrivateKey describes the encoding of the subject private
   key, see Section 3.6.  All columns are mandatory.  For values in the
   interval [-24, 23] the registration procedure is "IETF Review with
   Expert Review".  For all other values the registration procedure is
   "Expert Review".  The initial contents of the registry are:

   +-------+-----------------------------------------------------------+
   | Value | Private Key                                               |
   +=======+===========================================================+
   |     0 | Comments:          Asymmetric Key Package (RFC 5958)      |
   |       | subjectPrivateKey: PrivateKey OCTET STRING encoded as     |
   |       | CBOR byte string                                          |
   +-------+-----------------------------------------------------------+
   |     1 | Comments:          COSE Key Object (RFC 9052)             |
   |       | subjectPrivateKey: COSE_Key containing a private key      |
   +-------+-----------------------------------------------------------+

                      Figure 8: C509 Private Key Types

8.5.  C509 Certification Request Templates Types Registry

   IANA has created a new registry titled "C509 Certification Request
   Templates Types" under the new registry group "CBOR Encoded X.509
   (C509)".  The columns of the registry are Value, Description, and
   Reference, where Value is an integer, and the other columns are text
   strings.  All columns are mandatory.  For values in the interval
   [-24, 23] the registration procedure is "IETF Review with Expert
   Review".  For all other values the registration procedure is "Expert



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   Review".  The initial contents of the registry are:

   +-------+-----------------------------------------------------------+
   | Value | Description                                               |
   +=======+===========================================================+
   |     0 | Simple C509 Certification Request Template                |
   +-------+-----------------------------------------------------------+

            Figure 9: C509 Certification Request Templates Types

8.6.  C509 RDN Attributes Registry

   IANA has created a new registry titled "C509 RDN Attributes" in the
   new registry group "CBOR Encoded X.509 (C509)".  The fields of the
   registry are Value, Name, Identifiers, OID, DER, Comments and
   Reference, where Value is a non-negative integer, and the other
   columns are text strings.  Name and Identifiers are informal
   descriptions.  The fields Name, OID, and DER are mandatory.  For RDN
   Attributes specified only for CBOR encoded certificates where no OID
   is defined, the OID and DER fields are marked "N/A".  If there is an
   OID defined, the OID is given in dotted decimal representation, and
   the DER column contains the hex string of the DER-encoded OID
   [X.690].  If it is not expected to be understood from the other
   information (e.g. the OID), then the Comments field must contain a
   reference to where the RDN Attribute is described.  For values in the
   interval [0, 23] the registration procedure is "IETF Review with
   Expert Review".  Values ≥ 32768 are reserved for Private Use. For all
   other values the registration procedure is "Expert Review".

   The initial contents of the registry are:

   +-------+-----------------------------------------------------------+
   | Value | RDN Attribute                                             |
   +=======+===========================================================+
   |     0 | Name:            Email Address                            |
   |       | Identifiers:     emailAddress, e-mailAddress              |
   |       | OID:             1.2.840.113549.1.9.1                     |
   |       | DER:             06 09 2A 86 48 86 F7 0D 01 09 01         |
   |       | Comments:        RFC 2985                                 |
   +-------+-----------------------------------------------------------+
   |     1 | Name:            Common Name                              |
   |       | Identifiers:     commonName, cn                           |
   |       | OID:             2.5.4.3                                  |
   |       | DER:             06 03 55 04 03                           |
   |       | Comments:        X.520                                    |
   +-------+-----------------------------------------------------------+
   |     2 | Name:            Surname                                  |
   |       | Identifiers:     surname, sn                              |



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   |       | OID:             2.5.4.4                                  |
   |       | DER:             06 03 55 04 04                           |
   |       | Comments:        X.520                                    |
   +-------+-----------------------------------------------------------+
   |     3 | Name:            Serial Number                            |
   |       | Identifiers:     serialNumber                             |
   |       | OID:             2.5.4.5                                  |
   |       | DER:             06 03 55 04 05                           |
   |       | Comments:        X.520                                    |
   +-------+-----------------------------------------------------------+
   |     4 | Name:            Country                                  |
   |       | Identifiers:     countryName, c                           |
   |       | OID:             2.5.4.6                                  |
   |       | DER:             06 03 55 04 06                           |
   |       | Comments:        X.520                                    |
   +-------+-----------------------------------------------------------+
   |     5 | Name:            Locality                                 |
   |       | Identifiers:     localityName, locality, l                |
   |       | OID:             2.5.4.7                                  |
   |       | DER:             06 03 55 04 07                           |
   |       | Comments:        X.520                                    |
   +-------+-----------------------------------------------------------+
   |     6 | Name:            State or Province                        |
   |       | Identifiers:     stateOrProvinceName, st                  |
   |       | OID:             2.5.4.8                                  |
   |       | DER:             06 03 55 04 08                           |
   |       | Comments:        X.520                                    |
   +-------+-----------------------------------------------------------+
   |     7 | Name:            Street Address                           |
   |       | Identifiers:     streetAddress, street                    |
   |       | OID:             2.5.4.9                                  |
   |       | DER:             06 03 55 04 09                           |
   |       | Comments:        X.520                                    |
   +-------+-----------------------------------------------------------+
   |     8 | Name:            Organization                             |
   |       | Identifiers:     organizationName, o                      |
   |       | OID:             2.5.4.10                                 |
   |       | DER:             06 03 55 04 0A                           |
   |       | Comments:        X.520                                    |
   +-------+-----------------------------------------------------------+
   |     9 | Name:            Organizational Unit                      |
   |       | Identifiers:     organizationalUnitName, ou               |
   |       | OID:             2.5.4.11                                 |
   |       | DER:             06 03 55 04 0B                           |
   |       | Comments:        X.520                                    |
   +-------+-----------------------------------------------------------+
   |    10 | Name:            Title                                    |
   |       | Identifiers:     title                                    |



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   |       | OID:             2.5.4.12                                 |
   |       | DER:             06 03 55 04 0C                           |
   |       | Comments:        X.520                                    |
   +-------+-----------------------------------------------------------+
   |    11 | Name:            Business Category                        |
   |       | Identifiers:     businessCategory                         |
   |       | OID:             2.5.4.15                                 |
   |       | DER:             06 03 55 04 0F                           |
   |       | Comments:        X.520                                    |
   +-------+-----------------------------------------------------------+
   |    12 | Name:            Postal Code                              |
   |       | Identifiers:     postalCode                               |
   |       | OID:             2.5.4.17                                 |
   |       | DER:             06 03 55 04 11                           |
   |       | Comments:        X.520                                    |
   +-------+-----------------------------------------------------------+
   |    13 | Name:            Given Name                               |
   |       | Identifiers:     givenName                                |
   |       | OID:             2.5.4.42                                 |
   |       | DER:             06 03 55 04 2A                           |
   |       | Comments:        X.520                                    |
   +-------+-----------------------------------------------------------+
   |    14 | Name:            Initials                                 |
   |       | Identifiers:     initials                                 |
   |       | OID:             2.5.4.43                                 |
   |       | DER:             06 03 55 04 2B                           |
   |       | Comments:        X.520                                    |
   +-------+-----------------------------------------------------------+
   |    15 | Name:            Generation Qualifier                     |
   |       | Identifiers:     generationQualifier                      |
   |       | OID:             2.5.4.44                                 |
   |       | DER:             06 03 55 04 2C                           |
   |       | Comments:        X.520                                    |
   +-------+-----------------------------------------------------------+
   |    16 | Name:            DN Qualifier                             |
   |       | Identifiers:     dnQualifier                              |
   |       | OID:             2.5.4.46                                 |
   |       | DER:             06 03 55 04 2E                           |
   |       | Comments:        X.520                                    |
   +-------+-----------------------------------------------------------+
   |    17 | Name:            Pseudonym                                |
   |       | Identifiers:     pseudonym                                |
   |       | OID:             2.5.4.65                                 |
   |       | DER:             06 03 55 04 41                           |
   |       | Comments:        X.520                                    |
   +-------+-----------------------------------------------------------+
   |    18 | Name:            Organization Identifier                  |
   |       | Identifiers:     organizationIdentifier                   |



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   |       | OID:             2.5.4.97                                 |
   |       | DER:             06 03 55 04 61                           |
   |       | Comments:        X.520                                    |
   +-------+-----------------------------------------------------------+
   |    19 | Name:            Jurisdiction Locality Name               |
   |       | Identifiers:     jurisdictionLocalityName                 |
   |       | OID:             1.3.6.1.4.1.311.60.2.1.1                 |
   |       | DER:             06 0B 2B 06 01 04 01 82 37 3C 02 01 01   |
   |       | Comments:        Proprietary Microsoft Attribute          |
   +-------+-----------------------------------------------------------+
   |    20 | Name:            Jurisdiction State or Province           |
   |       | Identifiers:     jurisdictionStateOrProvinceName          |
   |       | OID:             1.3.6.1.4.1.311.60.2.1.2                 |
   |       | DER:             06 0B 2B 06 01 04 01 82 37 3C 02 01 02   |
   |       | Comments:        Proprietary Microsoft Attribute          |
   +-------+-----------------------------------------------------------+
   |    21 | Name:            Jurisdiction Country Name                |
   |       | Identifiers:     jurisdictionCountryName                  |
   |       | OID:             1.3.6.1.4.1.311.60.2.1.3                 |
   |       | DER:             06 0B 2B 06 01 04 01 82 37 3C 02 01 03   |
   |       | Comments:        Proprietary Microsoft Attribute          |
   +-------+-----------------------------------------------------------+
   |    22 | Name:            Domain Component                         |
   |       | Identifiers:     domainComponent, dc                      |
   |       | OID:             0.9.2342.19200300.100.1.25               |
   |       | DER:             06 0A 09 92 26 89 93 F2 2C 64 01 19      |
   |       | Comments:        RFC 4524                                 |
   +-------+-----------------------------------------------------------+
   |    25 | Name:            Name                                     |
   |       | Identifiers:     name                                     |
   |       | OID:             2.5.4.41                                 |
   |       | DER:             06 03 55 04 29                           |
   |       | Comments:        X.520                                    |
   +-------+-----------------------------------------------------------+
   |    26 | Name:            Telephone Number                         |
   |       | Identifiers:     telephoneNumber                          |
   |       | OID:             2.5.4.20                                 |
   |       | DER:             06 03 55 04 14                           |
   |       | Comments:        X.520                                    |
   +-------+-----------------------------------------------------------+
   |    27 | Name:            Directory Management Domain Name         |
   |       | Identifiers:     dmdName                                  |
   |       | OID:             2.5.4.54                                 |
   |       | DER:             06 03 55 04 36                           |
   |       | Comments:        X.520                                    |
   +-------+-----------------------------------------------------------+
   |    28 | Name:            userid                                   |
   |       | Identifiers:     uid                                      |



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   |       | OID:             0.9.2342.19200300.100.1.1                |
   |       | DER:             06 0A 09 92 26 89 93 F2 2C 64 01 01      |
   |       | Comments:        RFC 4524                                 |
   +-------+-----------------------------------------------------------+
   |    29 | Name:            Unstructured Name                        |
   |       | Identifiers:     unstructuredName                         |
   |       | OID:             1.2.840.113549.1.9.2                     |
   |       | DER:             06 09 2A 86 48 86 F7 0D 01 09 02         |
   |       | Comments:        RFC 2985                                 |
   +-------+-----------------------------------------------------------+
   |    30 | Name:            Unstructured Address                     |
   |       | Identifiers:     unstructuredAddress                      |
   |       | OID:             1.2.840.113549.1.9.8                     |
   |       | DER:             06 0A 2A 86 48 86 F7 0D 01 09 08         |
   |       | Comments:        RFC 2985                                 |
   +-------+-----------------------------------------------------------+

                       Figure 10: C509 RDN Attributes

8.7.  C509 CR Attributes Registry

   IANA has created a new registry titled "C509 CR Attributes" under the
   registry group "CBOR Encoded X.509 (C509)".  The fields of the
   registry are Value, Name, Identifiers, OID, DER, Comments,
   attributeValue, and Reference, where Value is an integer, and the
   other columns are text strings.  Name and Identifiers are informal
   descriptions.  The fields Name, OID, and DER are mandatory.  For CR
   Attributes specified only for CBOR encoded certificates where no OID
   is defined, the OID and DER fields are marked "N/A".  If OID is
   present, the OID is given in dotted decimal representation, and the
   DER column contains the hex string of the DER-encoded OID [X.690].
   If it is not expected to be understood from the other information
   (e.g. the OID), then the Comments field must contain a reference to
   where the CR Attribute is described.  For values in the interval
   [-24, 23] the registration procedure is "IETF Review with Expert
   Review".  Values ≥ 32768 are reserved for Private Use. For all other
   values the registration procedure is "Expert Review".

   The initial contents of the registry are:












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   +-------+-----------------------------------------------------------+
   | Value | CR Attribute                                              |
   +=======+===========================================================+
   |     0 | Name:            Extension Request                        |
   |       | Identifiers:     extensionRequest                         |
   |       | OID:             1.2.840.113549.1.9.14                    |
   |       | DER:             06 09 2A 86 48 86 F7 0D 01 09 0E         |
   |       | Comments:        RFC 2985                                 |
   |       | attributeValue:  Extensions                               |
   +-------+-----------------------------------------------------------+
   |     1 | Name:            Challenge Password                       |
   |       | Identifiers:     challengePassword                        |
   |       | OID:             1.2.840.113549.1.9.7                     |
   |       | DER:             06 09 2A 86 48 86 F7 0D 01 09 07         |
   |       | Comments:        RFC 2985                                 |
   |       | attributeValue:  ChallengePassword                        |
   +-------+-----------------------------------------------------------+
   |     2 | Name:            Private Key Possession Statement         |
   |       | Identifiers:     privateKeyPossessionStatement            |
   |       | OID:             1.3.6.1.4.1.22112.2.1                    |
   |       | DER:             06 0A 2B 06 01 04 01 81 AC 60 02 01      |
   |       | Comments:        RFC 9883                                 |
   |       | attributeValue:  PrivateKeyPossessionStatement            |
   +-------+-----------------------------------------------------------+

                        Figure 11: C509 CRAttributes

8.8.  C509 Extensions Registry

   IANA has created a new registry titled "C509 Extensions" under the
   new registry group "CBOR Encoded X.509 (C509)".  The fields of the
   registry are Value, Name, Identifiers, OID, DER, Comments,
   extensionValue, and Reference, where Value is a positive integer, and
   the other columns are text strings.  The fields Name, OID, DER, and
   extensionValue are mandatory.  For all other values the registration
   procedure is "Expert Review".  For Extensions specified only for CBOR
   encoded certificates where no OID is defined, the OID and DER fields
   are marked "N/A".  If it is not expected to be understood from the
   other information (e.g. the OID), then the Comments field must
   contain a reference to where the Extension is described.  For values
   in the interval [1, 23] the registration procedure is "IETF Review
   with Expert Review".  Values ≥ 32768 are reserved for Private Use.

   The initial contents of the registry are:







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   +-------+-----------------------------------------------------------+
   | Value | Extension                                                 |
   +=======+===========================================================+
   |     1 | Name:            Subject Key Identifier                   |
   |       | Identifiers:     subjectKeyIdentifier                     |
   |       | OID:             2.5.29.14                                |
   |       | DER:             06 03 55 1D 0E                           |
   |       | Comments:        RFC 5280                                 |
   |       | extensionValue:  SubjectKeyIdentifier                     |
   +-------+-----------------------------------------------------------+
   |     2 | Name:            Key Usage                                |
   |       | Identifiers:     keyUsage                                 |
   |       | OID:             2.5.29.15                                |
   |       | DER:             06 03 55 1D 0F                           |
   |       | Comments:        RFC 5280                                 |
   |       | extensionValue:  KeyUsage                                 |
   +-------+-----------------------------------------------------------+
   |     3 | Name:            Subject Alternative Name                 |
   |       | Identifiers:     subjectAltName                           |
   |       | OID:             2.5.29.17                                |
   |       | DER:             06 03 55 1D 11                           |
   |       | Comments:        RFC 5280                                 |
   |       | extensionValue:  SubjectAltName                           |
   +-------+-----------------------------------------------------------+
   |     4 | Name:            Basic Constraints                        |
   |       | Identifiers:     basicConstraints                         |
   |       | OID:             2.5.29.19                                |
   |       | DER:             06 03 55 1D 13                           |
   |       | Comments:        RFC 5280                                 |
   |       | extensionValue:  BasicConstraints                         |
   +-------+-----------------------------------------------------------+
   |     5 | Name:            CRL Distribution Points                  |
   |       | Identifiers:     cRLDistributionPoints                    |
   |       | OID:             2.5.29.31                                |
   |       | DER:             06 03 55 1D 1F                           |
   |       | Comments:        RFC 5280                                 |
   |       | extensionValue:  CRLDistributionPoints                    |
   +-------+-----------------------------------------------------------+
   |     6 | Name:            Certificate Policies                     |
   |       | Identifiers:     certificatePolicies                      |
   |       | OID:             2.5.29.32                                |
   |       | DER:             06 03 55 1D 20                           |
   |       | Comments:        RFC 5280                                 |
   |       | extensionValue:  CertificatePolicies                      |
   +-------+-----------------------------------------------------------+
   |     7 | Name:            Authority Key Identifier                 |
   |       | Identifiers:     authorityKeyIdentifier                   |
   |       | OID:             2.5.29.35                                |



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   |       | DER:             06 03 55 1D 23                           |
   |       | Comments:        RFC 5280                                 |
   |       | extensionValue:  AuthorityKeyIdentifier                   |
   +-------+-----------------------------------------------------------+
   |     8 | Name:            Extended Key Usage                       |
   |       | Identifiers:     extKeyUsage                              |
   |       | OID:             2.5.29.37                                |
   |       | DER:             06 03 55 1D 25                           |
   |       | Comments:        RFC 5280                                 |
   |       | extensionValue:  ExtKeyUsageSyntax                        |
   +-------+-----------------------------------------------------------+
   |     9 | Name:            Authority Information Access             |
   |       | Identifiers:     authorityInfoAccess                      |
   |       | OID:             1.3.6.1.5.5.7.1.1                        |
   |       | DER:             06 08 2B 06 01 05 05 07 01 01            |
   |       | Comments:        RFC 5280                                 |
   |       | extensionValue:  AuthorityInfoAccessSyntax                |
   +-------+-----------------------------------------------------------+
   |    24 | Name:            Subject Directory Attributes             |
   |       | Identifiers:     subjectDirectoryAttributes               |
   |       | OID:             2.5.29.9                                 |
   |       | DER:             06 03 55 1D 09                           |
   |       | Comments:        RFC 5280                                 |
   |       | extensionValue:  SubjectDirectoryAttributes               |
   +-------+-----------------------------------------------------------+
   |    25 | Name:            Issuer Alternative Name                  |
   |       | Identifiers:     issuerAltName                            |
   |       | OID:             2.5.29.18                                |
   |       | DER:             06 03 55 1D 12                           |
   |       | Comments:        RFC 5280                                 |
   |       | extensionValue:  IssuerAltName                            |
   +-------+-----------------------------------------------------------+
   |    26 | Name:            Name Constraints                         |
   |       | Identifiers:     nameConstraints                          |
   |       | OID:             2.5.29.30                                |
   |       | DER:             06 03 55 1D 1E                           |
   |       | Comments:        RFC 9549                                 |
   |       | extensionValue:  NameConstraints                          |
   +-------+-----------------------------------------------------------+
   |    27 | Name:            Policy Mappings                          |
   |       | Identifiers:     policyMappings                           |
   |       | OID:             2.5.29.33                                |
   |       | DER:             06 03 55 1D 21                           |
   |       | Comments:        RFC 5280                                 |
   |       | extensionValue:  PolicyMappings                           |
   +-------+-----------------------------------------------------------+
   |    28 | Name:            Policy Constraints                       |
   |       | Identifiers:     policyConstraints                        |



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   |       | OID:             2.5.29.36                                |
   |       | DER:             06 03 55 1D 24                           |
   |       | Comments:        RFC 5280                                 |
   |       | extensionValue:  PolicyConstraints                        |
   +-------+-----------------------------------------------------------+
   |    29 | Name:            Freshest CRL                             |
   |       | Identifiers:     freshestCRL                              |
   |       | OID:             2.5.29.46                                |
   |       | DER:             06 03 55 1D 2E                           |
   |       | Comments:        RFC 5280                                 |
   |       | extensionValue:  FreshestCRL                              |
   +-------+-----------------------------------------------------------+
   |    30 | Name:            Inhibit anyPolicy                        |
   |       | Identifiers:     inhibitAnyPolicy                         |
   |       | OID:             2.5.29.54                                |
   |       | DER:             06 03 55 1D 36                           |
   |       | Comments:        RFC 5280                                 |
   |       | extensionValue:  InhibitAnyPolicy                         |
   +-------+-----------------------------------------------------------+
   |    31 | Name:            Subject Information Access               |
   |       | Identifiers:     subjectInfoAccess                        |
   |       | OID:             1.3.6.1.5.5.7.1.11                       |
   |       | DER:             06 08 2B 06 01 05 05 07 01 0B            |
   |       | Comments:        RFC 5280                                 |
   |       | extensionValue:  SubjectInfoAccessSyntax                  |
   +-------+-----------------------------------------------------------+
   |    32 | Name:            IPAddrBlocks                             |
   |       | Identifiers:     id-pe-ipAddrBlocks                       |
   |       | OID:             1.3.6.1.5.5.7.1.7                        |
   |       | DER:             06 08 2B 06 01 05 05 07 01 07            |
   |       | Comments:        RFC 3779                                 |
   |       | extensionValue:  IPAddrBlocks                             |
   +-------+-----------------------------------------------------------+
   |    33 | Name:            AS Identifiers                           |
   |       | Identifiers:     id-pe-autonomousSysIds                   |
   |       | OID:             1.3.6.1.5.5.7.1.8                        |
   |       | DER:             06 08 2B 06 01 05 05 07 01 08            |
   |       | Comments:        RFC 3779                                 |
   |       | extensionValue:  ASIdentifiers                            |
   +-------+-----------------------------------------------------------+
   |    34 | Name:            IPAddrBlocks v2                          |
   |       | Identifiers:     id-pe-ipAddrBlocks-v2                    |
   |       | OID:             1.3.6.1.5.5.7.1.28                       |
   |       | DER:             06 08 2B 06 01 05 05 07 01 1C            |
   |       | Comments:        RFC 8360                                 |
   |       | extensionValue:  IPAddrBlocks                             |
   +-------+-----------------------------------------------------------+
   |    35 | Name:            AS Identifiers v2                        |



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   |       | Identifiers:     id-pe-autonomousSysIds-v2                |
   |       | OID:             1.3.6.1.5.5.7.1.29                       |
   |       | DER:             06 08 2B 06 01 05 05 07 01 1D            |
   |       | Comments:        RFC 8360                                 |
   |       | extensionValue:  ASIdentifiers                            |
   +-------+-----------------------------------------------------------+
   |    36 | Name:            OCSP No Check                            |
   |       | Identifiers:     id-pkix-ocsp-nocheck                     |
   |       | OID:             1.3.6.1.5.5.7.48.1.5                     |
   |       | DER:             06 09 2B 06 01 05 05 07 30 01 05         |
   |       | Comments:        RFC 6960                                 |
   |       | extensionValue:  null                                     |
   +-------+-----------------------------------------------------------+
   |    38 | Name:            TLS Features                             |
   |       | Identifiers:     id-pe-tlsfeature                         |
   |       | OID:             1.3.6.1.5.5.7.1.24                       |
   |       | DER:             06 08 2B 06 01 05 05 07 01 18            |
   |       | Comments:        RFC 7633                                 |
   |       | extensionValue:  TLSFeatures                              |
   +-------+-----------------------------------------------------------+

                         Figure 12: C509 Extensions

8.9.  C509 Certificate Policies Registry

   IANA has created a new registry titled "C509 Certificate Policies"
   under the registry group "CBOR Encoded X.509 (C509)".  The fields of
   the registry are Value, Name, Identifiers, OID, DER, Comments, and
   Reference, where Value is an integer, and the other columns are text
   strings.  The fields Name, OID, and DER are mandatory.  For all other
   values the registration procedure is "Expert Review".  For
   Certificate Policies specified only for CBOR encoded certificates
   where no OID is defined, the OID and DER fields are marked "N/A".  If
   it is not expected to be understood from the other information (e.g.
   the OID), then the Comments field must contain a reference to where
   the Certificate Policy is described.  For values in the interval
   [-24, 23] the registration procedure is "IETF Review with Expert
   Review".  Values ≥ 32768 are reserved for Private Use.

   The initial contents of the registry are:

   +-------+-----------------------------------------------------------+
   | Value | Certificate Policy                                        |
   +=======+===========================================================+
   |     0 | Name:            Any Policy                               |
   |       | Identifiers:     anyPolicy                                |
   |       | OID:             2.5.29.32.0                              |
   |       | DER:             06 04 55 1D 20 00                        |



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   |       | Comments:        RFC 5280                                 |
   +-------+-----------------------------------------------------------+
   |     1 | Name:            Domain Validation (DV)                   |
   |       | Identifiers:     domain-validated                         |
   |       | OID:             2.23.140.1.2.1                           |
   |       | DER:             06 06 67 81 0C 01 02 01                  |
   |       | Comments:        CA/Browser Forum                         |
   +-------+-----------------------------------------------------------+
   |     2 | Name:            Organization Validation (OV)             |
   |       | Identifiers:     organization-validated                   |
   |       | OID:             2.23.140.1.2.2                           |
   |       | DER:             06 06 67 81 0C 01 02 02                  |
   |       | Comments:        CA/Browser Forum                         |
   +-------+-----------------------------------------------------------+
   |     3 | Name:            Individual Validation (IV)               |
   |       | Identifiers:     individual-validated                     |
   |       | OID:             2.23.140.1.2.3                           |
   |       | DER:             06 06 67 81 0C 01 02 03                  |
   |       | Comments:        CA/Browser Forum                         |
   +-------+-----------------------------------------------------------+
   |     4 | Name:            Extended Validation (EV)                 |
   |       | Identifiers:     ev-guidelines                            |
   |       | OID:             2.23.140.1.1                             |
   |       | DER:             06 05 67 81 0C 01 01                     |
   |       | Comments:        CA/Browser Forum                         |
   +-------+-----------------------------------------------------------+
   |     7 | Name:            Resource PKI (RPKI)                      |
   |       | Identifiers:     id-cp-ipAddr-asNumber                    |
   |       | OID:             1.3.6.1.5.5.7.14.2                       |
   |       | DER:             06 08 2B 06 01 05 05 07 0E 02            |
   |       | Comments:        RFC 3779                                 |
   +-------+-----------------------------------------------------------+
   |     8 | Name:            Resource PKI (RPKI) (Alternative)        |
   |       | Identifiers:     id-cp-ipAddr-asNumber-v2                 |
   |       | OID:             1.3.6.1.5.5.7.14.3                       |
   |       | DER:             06 08 2B 06 01 05 05 07 0E 03            |
   |       | Comments:        RFC 8360                                 |
   +-------+-----------------------------------------------------------+
   |    24 | Name:            Remote SIM Provisioning Role             |
   |       |                  Certificate Issuer                       |
   |       | Identifiers:     id-rspRole-ci                            |
   |       | OID:             2.23.146.1.2.1.0                         |
   |       | DER:             06 07 67 81 12 01 02 01 00               |
   |       | Comments:        GSMA SGP.22                              |
   +-------+-----------------------------------------------------------+
   |    25 | Name:            Remote SIM Provisioning Role             |
   |       |                  eUICC v2                                 |
   |       | Identifiers:     id-rspRole-euicc-v2                      |



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   |       | OID:             2.23.146.1.2.1.1                         |
   |       | DER:             06 07 67 81 12 01 02 01 01               |
   |       | Comments:        GSMA SGP.22                              |
   +-------+-----------------------------------------------------------+
   |    26 | Name:            Remote SIM Provisioning Role             |
   |       |                  eUICC                                    |
   |       | Identifiers:     id-rspRole-euicc                         |
   |       | OID:             2.23.146.1.2.1.0.0.0.0.0                 |
   |       | DER:             06 0B 67 81 12 01 02 01 00 00 00 00 00   |
   |       | Comments:        GSMA SGP.22                              |
   +-------+-----------------------------------------------------------+
   |    27 | Name:            Remote SIM Provisioning Role             |
   |       |                  eUICC Manufacturer v2                    |
   |       | Identifiers:     id-rspRole-eum-v2                        |
   |       | OID:             2.23.146.1.2.1.2                         |
   |       | DER:             06 07 67 81 12 01 02 01 02               |
   |       | Comments:        GSMA SGP.22                              |
   +-------+-----------------------------------------------------------+
   |    28 | Name:            Remote SIM Provisioning Role             |
   |       |                  eUICC Manufacturer                       |
   |       | Identifiers:     id-rspRole-eum                           |
   |       | OID:             2.23.146.1.2.1.0.0.0                     |
   |       | DER:             06 09 67 81 12 01 02 01 00 00 00         |
   |       | Comments:        GSMA SGP.22                              |
   +-------+-----------------------------------------------------------+
   |    29 | Name:            Remote SIM Provisioning Role             |
   |       |                  SM-DP+ TLS v2                            |
   |       | Identifiers:     id-rspRole-dp-tls-v2                     |
   |       | OID:             2.23.146.1.2.1.3                         |
   |       | DER:             06 07 67 81 12 01 02 01 03               |
   |       | Comments:        GSMA SGP.22                              |
   +-------+-----------------------------------------------------------+
   |    30 | Name:            Remote SIM Provisioning Role             |
   |       |                  SM-DP+ TLS                               |
   |       | Identifiers:     id-rspRole-dp-tls                        |
   |       | OID:             2.23.146.1.2.1.0.0.1.0                   |
   |       | DER:             06 0A 67 81 12 01 02 01 00 00 01 00      |
   |       | Comments:        GSMA SGP.22                              |
   +-------+-----------------------------------------------------------+
   |    31 | Name:            Remote SIM Provisioning Role             |
   |       |                  SM-DP+ Authentication v2                 |
   |       | Identifiers:     id-rspRole-dp-auth-v2                    |
   |       | OID:             2.23.146.1.2.1.4                         |
   |       | DER:             06 07 67 81 12 01 02 01 04               |
   |       | Comments:        GSMA SGP.22                              |
   +-------+-----------------------------------------------------------+
   |    32 | Name:            Remote SIM Provisioning Role             |
   |       |                  SM-DP+ Authentication                    |



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   |       | Identifiers:     id-rspRole-dp-auth                       |
   |       | OID:             2.23.146.1.2.1.0.0.1.1                   |
   |       | DER:             06 0A 67 81 12 01 02 01 00 00 01 01      |
   |       | Comments:        GSMA SGP.22                              |
   +-------+-----------------------------------------------------------+
   |    33 | Name:            Remote SIM Provisioning Role             |
   |       |                  SM-DP+ Profile Binding v2                |
   |       | Identifiers:     id-rspRole-dp-pb-v2                      |
   |       | OID:             2.23.146.1.2.1.5                         |
   |       | DER:             06 07 67 81 12 01 02 01 05               |
   |       | Comments:        GSMA SGP.22                              |
   +-------+-----------------------------------------------------------+
   |    34 | Name:            Remote SIM Provisioning Role             |
   |       |                  SM-DP+ Profile Binding                   |
   |       | Identifiers:     id-rspRole-dp-pb                         |
   |       | OID:             2.23.146.1.2.1.0.0.1.2                   |
   |       | DER:             06 0A 67 81 12 01 02 01 00 00 01 02      |
   |       | Comments:        GSMA SGP.22                              |
   +-------+-----------------------------------------------------------+
   |    35 | Name:            Remote SIM Provisioning Role             |
   |       |                  SM-DS TLS v2                             |
   |       | Identifiers:     id-rspRole-ds-tls-v2                     |
   |       | OID:             2.23.146.1.2.1.6                         |
   |       | DER:             06 07 67 81 12 01 02 01 06               |
   |       | Comments:        GSMA SGP.22                              |
   +-------+-----------------------------------------------------------+
   |    36 | Name:            Remote SIM Provisioning Role             |
   |       |                  SM-DS TLS                                |
   |       | Identifiers:     id-rspRole-ds-tls                        |
   |       | OID:             2.23.146.1.2.1.0.0.2.0                   |
   |       | DER:             06 0A 67 81 12 01 02 01 00 00 02 00      |
   |       | Comments:        GSMA SGP.22                              |
   +-------+-----------------------------------------------------------+
   |    37 | Name:            Remote SIM Provisioning Role             |
   |       |                  SM-DS Authentication v2                  |
   |       | Identifiers:     id-rspRole-ds-auth-v2                    |
   |       | OID:             2.23.146.1.2.1.7                         |
   |       | DER:             06 07 67 81 12 01 02 01 07               |
   |       | Comments:        GSMA SGP.22                              |
   +-------+-----------------------------------------------------------+
   |    38 | Name:            Remote SIM Provisioning Role             |
   |       |                  SM-DS Authentication                     |
   |       | Identifiers:     id-rspRole-ds-auth                       |
   |       | OID:             2.23.146.1.2.1.0.0.2.1                   |
   |       | DER:             06 0A 67 81 12 01 02 01 00 00 02 01      |
   |       | Comments:        GSMA SGP.22                              |
   +-------+-----------------------------------------------------------+




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                    Figure 13: C509 Certificate Policies

8.10.  C509 Policies Qualifiers Registry

   IANA has created a new registry titled "C509 Policies Qualifiers"
   under the registry group "CBOR Encoded X.509 (C509)".  The fields of
   the registry are Value, Name, Identifiers, OID, DER, Comments, and
   Reference, where Value is an integer, and the other columns are text
   strings.  The fields Name, OID, and DER are mandatory.  If it is not
   expected to be understood from the other information (e.g. the OID),
   then the Comments field must contain a reference to where the Policy
   Qualifier is described.  For values in the interval [-24, 23] the
   registration procedure is "IETF Review with Expert Review".  Values ≥
   32768 are reserved for Private Use. For all other values the
   registration procedure is "Expert Review".

   The initial contents of the registry are:

   +-------+-----------------------------------------------------------+
   | Value | Policy Qualifier                                          |
   +=======+===========================================================+
   |     1 | Name:            Certification Practice Statement         |
   |       | Identifiers:     id-qt-cps, cps                           |
   |       | OID:             1.3.6.1.5.5.7.2.1                        |
   |       | DER:             06 08 2B 06 01 05 05 07 02 01            |
   |       | Comments:        RFC 5280                                 |
   +-------+-----------------------------------------------------------+
   |     2 | Name:            User Notice                              |
   |       | Identifiers:     id-qt-unotice, unotice                   |
   |       | OID:             1.3.6.1.5.5.7.2.2                        |
   |       | DER:             06 08 2B 06 01 05 05 07 02 02            |
   |       | Comments:        RFC 5280                                 |
   +-------+-----------------------------------------------------------+

                    Figure 14: C509 Policies Qualifiers

8.11.  C509 Information Access Registry

   IANA has created a new registry titled "C509 Information Access"
   under the registry group "CBOR Encoded X.509 (C509)".  The fields of
   the registry are Value, Name, Identifiers, OID, DER, Comments, and
   Reference, where Value is an integer, and the other columns are text
   strings.  The fields Name, OID, and DER are mandatory.  If it is not
   expected to be understood from the other information (e.g. the OID),
   then the Comments field must contain a reference to where the
   Information Access is described.  For values in the interval [-24,
   23] the registration procedure is "IETF Review with Expert Review".
   For all other values the registration procedure is "Expert Review".



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   The initial contents of the registry are:

   +-------+-----------------------------------------------------------+
   | Value | Information Access                                        |
   +=======+===========================================================+
   |     1 | Name:            OCSP                                     |
   |       | Identifiers:     id-ad-ocsp, id-pkix-ocsp                 |
   |       | OID:             1.3.6.1.5.5.7.48.1                       |
   |       | DER:             06 08 2B 06 01 05 05 07 30 01            |
   |       | Comments:        RFC 5280                                 |
   +-------+-----------------------------------------------------------+
   |     2 | Name:            CA Issuers                               |
   |       | Identifiers:     id-ad-caIssuers, caIssuers               |
   |       | OID:             1.3.6.1.5.5.7.48.2                       |
   |       | DER:             06 08 2B 06 01 05 05 07 30 02            |
   |       | Comments:        RFC 5280                                 |
   +-------+-----------------------------------------------------------+
   |     3 | Name:            Time Stamping                            |
   |       | Identifiers:     id-ad-timeStamping, timeStamping         |
   |       | OID:             1.3.6.1.5.5.7.48.3                       |
   |       | DER:             06 08 2B 06 01 05 05 07 30 03            |
   |       | Comments:        RFC 3161                                 |
   +-------+-----------------------------------------------------------+
   |     5 | Name:            CA Repository                            |
   |       | Identifiers:     id-ad-caRepository                       |
   |       | OID:             1.3.6.1.5.5.7.48.5                       |
   |       | DER:             06 08 2B 06 01 05 05 07 30 05            |
   |       | Comments:        RFC 5280                                 |
   +-------+-----------------------------------------------------------+
   |    10 | Name:            RPKI Manifest                            |
   |       | Identifiers:     id-ad-rpkiManifest                       |
   |       | OID:             1.3.6.1.5.5.7.48.10                      |
   |       | DER:             06 08 2B 06 01 05 05 07 30 0A            |
   |       | Comments:        RFC 6487                                 |
   +-------+-----------------------------------------------------------+
   |    11 | Name:            Signed Object                            |
   |       | Identifiers:     id-ad-signedObject                       |
   |       | OID:             1.3.6.1.5.5.7.48.11                      |
   |       | DER:             06 08 2B 06 01 05 05 07 30 0B            |
   |       | Comments:        RFC 6487                                 |
   +-------+-----------------------------------------------------------+
   |    13 | Name:            RPKI Notify                              |
   |       | Identifiers:     id-ad-rpkiNotify                         |
   |       | OID:             1.3.6.1.5.5.7.48.13                      |
   |       | DER:             06 08 2B 06 01 05 05 07 30 0D            |
   |       | Comments:        RFC 8182                                 |
   +-------+-----------------------------------------------------------+




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                    Figure 15: C509 Information Accesses

8.12.  C509 Extended Key Usages Registry

   IANA has created a new registry titled "C509 Extended Key Usages"
   under the registry group "CBOR Encoded X.509 (C509)".  The fields of
   the registry are Value, Name, Identifiers, OID, DER, Comments, and
   Reference, where Value is an integer, and the other columns are text
   strings.  The fields Name, OID, and DER are mandatory.  For Extended
   Key Usage specified only for CBOR encoded certificates where no OID
   is defined, the OID and DER fields are marked "N/A".  If it is not
   expected to be understood from the other information (e.g. the OID),
   then the Comments field must contain a reference to where the
   Extended Key Usage is described.  For values in the interval [-24,
   23] the registration procedure is "IETF Review with Expert Review".
   Values ≥ 32768 are reserved for Private Use. For all other values the
   registration procedure is "Expert Review".

   The initial contents of the registry are:

    +-------+---------------------------------------------------------+
    | Value | Extended Key Usage                                      |
    +=======+=========================================================+
    |     0 | Name:            Any Extended Key Usage                 |
    |       | Identifiers:     anyExtendedKeyUsage                    |
    |       | OID:             2.5.29.37.0                            |
    |       | DER:             06 04 55 1D 25 00                      |
    |       | Comments:        RFC 5280                               |
    +-------+---------------------------------------------------------+
    |     1 | Name:            TLS Server authentication              |
    |       | Identifiers:     id-kp-serverAuth                       |
    |       | OID:             1.3.6.1.5.5.7.3.1                      |
    |       | DER:             06 08 2B 06 01 05 05 07 03 01          |
    |       | Comments:        RFC 5280                               |
    +-------+---------------------------------------------------------+
    |     2 | Name:            TLS Client Authentication              |
    |       | Identifiers:     id-kp-clientAuth                       |
    |       | OID:             1.3.6.1.5.5.7.3.2                      |
    |       | DER:             06 08 2B 06 01 05 05 07 03 02          |
    |       | Comments:        RFC 5280                               |
    +-------+---------------------------------------------------------+
    |     3 | Name:            Code Signing                           |
    |       | Identifiers:     id-kp-codeSigning                      |
    |       | OID:             1.3.6.1.5.5.7.3.3                      |
    |       | DER:             06 08 2B 06 01 05 05 07 03 03          |
    |       | Comments:        RFC 5280                               |
    +-------+---------------------------------------------------------+
    |     4 | Name:            Email protection (S/MIME)              |



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    |       | Identifiers:     id-kp-emailProtection                  |
    |       | OID:             1.3.6.1.5.5.7.3.4                      |
    |       | DER:             06 08 2B 06 01 05 05 07 03 04          |
    |       | Comments:        RFC 5280                               |
    +-------+---------------------------------------------------------+
    |     8 | Name:            Time Stamping                          |
    |       | Identifiers:     id-kp-timeStamping, timestamping       |
    |       | OID:             1.3.6.1.5.5.7.3.8                      |
    |       | DER:             06 08 2B 06 01 05 05 07 03 08          |
    |       | Comments:        RFC 3161                               |
    +-------+---------------------------------------------------------+
    |     9 | Name:            OCSP Signing                           |
    |       | Identifiers:     id-kp-OCSPSigning                      |
    |       | OID:             1.3.6.1.5.5.7.3.9                      |
    |       | DER:             06 08 2B 06 01 05 05 07 03 09          |
    |       | Comments:        RFC 5280                               |
    +-------+---------------------------------------------------------+
    |    10 | Name:            Kerberos PKINIT Client Auth            |
    |       | Identifiers:     id-pkinit-KPClientAuth                 |
    |       | OID:             1.3.6.1.5.2.3.4                        |
    |       | DER:             06 07 2B 06 01 05 02 03 04             |
    |       | Comments:        RFC 4556                               |
    +-------+---------------------------------------------------------+
    |    11 | Name:            Kerberos PKINIT KDC                    |
    |       | Identifiers:     id-pkinit-KPKdc                        |
    |       | OID:             1.3.6.1.5.2.3.5                        |
    |       | DER:             06 07 2B 06 01 05 02 03 05             |
    |       | Comments:        RFC 4556                               |
    +-------+---------------------------------------------------------+
    |    12 | Name:            SSH Client                             |
    |       | Identifiers:     id-kp-secureShellClient                |
    |       | OID:             1.3.6.1.5.5.7.3.21                     |
    |       | DER:             06 08 2B 06 01 05 05 07 03 15          |
    |       | Comments:        RFC 6187                               |
    +-------+---------------------------------------------------------+
    |    13 | Name:            SSH Server                             |
    |       | Identifiers:     id-kp-secureShellServer                |
    |       | OID:             1.3.6.1.5.5.7.3.22                     |
    |       | DER:             06 08 2B 06 01 05 05 07 03 16          |
    |       | Comments:        RFC 6187                               |
    +-------+---------------------------------------------------------+
    |    14 | Name:            Bundle Security                        |
    |       | Identifiers:     id-kp-bundleSecurity                   |
    |       | OID:             1.3.6.1.5.5.7.3.35                     |
    |       | DER:             06 08 2B 06 01 05 05 07 03 23          |
    |       | Comments:        RFC 9174                               |
    +-------+---------------------------------------------------------+
    |    15 | Name:            CMC Certification Authority            |



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    |       | Identifiers:     id-kp-cmcCA                            |
    |       | OID:             1.3.6.1.5.5.7.3.27                     |
    |       | DER:             06 08 2B 06 01 05 05 07 03 1B          |
    |       | Comments:        RFC 6402                               |
    +-------+---------------------------------------------------------+
    |    16 | Name:            CMC Registration Authority             |
    |       | Identifiers:     id-kp-cmcRA                            |
    |       | OID:             1.3.6.1.5.5.7.3.28                     |
    |       | DER:             06 08 2B 06 01 05 05 07 03 1C          |
    |       | Comments:        RFC 6402                               |
    +-------+---------------------------------------------------------+
    |    17 | Name:            CMC Archive Server                     |
    |       | Identifiers:     id-kp-cmcArchive                       |
    |       | OID:             1.3.6.1.5.5.7.3.29                     |
    |       | DER:             06 08 2B 06 01 05 05 07 03 1D          |
    |       | Comments:        RFC 6402                               |
    +-------+---------------------------------------------------------+
    |    18 | Name:            CMC Key Generation Authority           |
    |       | Identifiers:     id-kp-cmKGA                            |
    |       | OID:             1.3.6.1.5.5.7.3.32                     |
    |       | DER:             06 08 2B 06 01 05 05 07 03 20          |
    |       | Comments:        RFC 9480                               |
    +-------+---------------------------------------------------------+
    |    20 | Name:            Wi-SUN FAN Device                      |
    |       | Identifiers:     id-kp-wisun-fan-device                 |
    |       | OID:             1.3.6.1.4.1.45605.1                    |
    |       | DER:             06 09 2B 06 01 04 01 82 E4 25 01       |
    |       | Comments:                                               |
    +-------+---------------------------------------------------------+

                    Figure 16: C509 Extended Key Usages

8.13.  C509 General Names Registry

   IANA has created a new registry titled "C509 General Names" under the
   registry group "CBOR Encoded X.509 (C509)".  The fields of the
   registry are Value, Name, Comments, GeneralNameValue, and Reference,
   where Value is an integer, and the other columns are text strings.
   The fields Name and GeneralNameValue are mandatory.  If it is not
   expected to be understood from the other information (e.g. the OID),
   then the Comments field must contain a reference to where the General
   Name is described.  For values in the interval [-24, 23] the
   registration procedure is "IETF Review with Expert Review".  For all
   other values the registration procedure is "Expert Review".

   The initial contents of the registry are:





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   +-------+-----------------------------------------------------------+
   | Value | General Name                                              |
   +=======+===========================================================+
   |    -3 | Name:             otherName with MACAddress               |
   |       | Comments:         TBD92(Use RFC I-D-lamps-macaddress-on)  |
   |       |                   id-on-MACAddress                        |
   |       |                   (1.3.6.1.5.5.7.8.12)                    |
   |       |                   06 08 2B 06 01 05 05 07 08 0C           |
   |       | GeneralNameValue: bytes                                   |
   +-------+-----------------------------------------------------------+
   |    -2 | Name:             otherName with SmtpUTF8Mailbox          |
   |       | Comments:         RFC 9598                                |
   |       |                   id-on-SmtpUTF8Mailbox                   |
   |       |                   (1.3.6.1.5.5.7.8.9)                     |
   |       |                   06 08 2B 06 01 05 05 07 08 09           |
   |       | GeneralNameValue: text                                    |
   +-------+-----------------------------------------------------------+
   |    -1 | Name:             otherName with hardwareModuleName       |
   |       | Comments:         RFC 4108                                |
   |       |                   id-on-hardwareModuleName                |
   |       |                   (1.3.6.1.5.5.7.8.4)                     |
   |       |                   06 08 2B 06 01 05 05 07 08 04           |
   |       | GeneralNameValue: [ ~oid, bytes ]                         |
   +-------+-----------------------------------------------------------+
   |     0 | Name:             otherName                               |
   |       | Comments:         RFC 5280                                |
   |       | GeneralNameValue: [ ~oid, bytes ]                         |
   +-------+-----------------------------------------------------------+
   |     1 | Name:             rfc822Name                              |
   |       | Comments:         RFC 5280                                |
   |       | GeneralNameValue: text                                    |
   +-------+-----------------------------------------------------------+
   |     2 | Name:             dNSName                                 |
   |       | Comments:         RFC 5280                                |
   |       | GeneralNameValue: text                                    |
   +-------+-----------------------------------------------------------+
   |     4 | Name:             directoryName                           |
   |       | Comments:         RFC 5280                                |
   |       | GeneralNameValue: Name                                    |
   +-------+-----------------------------------------------------------+
   |     6 | Name:             uniformResourceIdentifier               |
   |       | Comments:         RFC 5280                                |
   |       | GeneralNameValue: text                                    |
   +-------+-----------------------------------------------------------+
   |     7 | Name:             iPAddress                               |
   |       | Comments:         RFC 5280                                |
   |       | GeneralNameValue: bytes                                   |
   +-------+-----------------------------------------------------------+



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   |     8 | Name:             registeredID                            |
   |       | Comments          RFC 5280                                |
   |       | GeneralNameValue: ~oid                                    |
   +-------+-----------------------------------------------------------+

                       Figure 17: C509 General Names

8.14.  C509 Signature Algorithms Registry

   IANA has created a new registry titled "C509 Signature Algorithms"
   under the registry group "CBOR Encoded X.509 (C509)".  The registry
   includes both signature algorithms and non-signature proof-of-
   possession algorithms.  The fields of the registry are Value, Name,
   Identifiers, OID, Parameters, DER, Comments, and Reference, where
   Value is an integer, and the other columns are text strings.  The
   fields Name, OID, Parameters, and DER are mandatory.  Alignment with
   the value of public key algorithm must be considered, see instruction
   in Section 8.15.  If it is not expected to be understood from the
   other information (e.g. the OID), then the Comments field must
   contain a reference to where the Signature Algorithm is described.
   For values in the interval [-24, 23] the registration procedure is
   "IETF Review with Expert Review".  For all other values the
   registration procedure is "Expert Review".  The initial contents of
   the registry are:

   +-------+-----------------------------------------------------------+
   | Value | Signature Algorithm                                       |
   +=======+===========================================================+
   |  -256 | Name:        RSASSA-PKCS1-v1_5 with SHA-1                 |
   |       | Identifiers: sha1-with-rsa-signature,                     |
   |       |              sha1WithRSAEncryption,                       |
   |       |              sha-1WithRSAEncryption                       |
   |       | OID:         1.2.840.113549.1.1.5                         |
   |       | Parameters:  NULL                                         |
   |       | DER:         30 0D 06 09 2A 86 48 86 F7 0D 01 01 05 05 00 |
   |       | Comments:                                                 |
   +-------+-----------------------------------------------------------+
   |  -255 | Name:        ECDSA with SHA-1                             |
   |       | Identifiers: ecdsa-with-SHA1                              |
   |       | OID:         1.2.840.10045.4.1                            |
   |       | Parameters:  Absent                                       |
   |       | DER:         30 09 06 07 2A 86 48 CE 3D 04 01             |
   |       | Comments:    See Section 3.2.2.                           |
   +-------+-----------------------------------------------------------+
   |     0 | Name:        ECDSA with SHA-256                           |
   |       | Identifiers: ecdsa-with-SHA256                            |
   |       | OID:         1.2.840.10045.4.3.2                          |
   |       | Parameters:  Absent                                       |



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   |       | DER:         30 0A 06 08 2A 86 48 CE 3D 04 03 02          |
   |       | Comments:    See Section 3.2.2.                           |
   +-------+-----------------------------------------------------------+
   |     1 | Name:        ECDSA with SHA-384                           |
   |       | Identifiers: ecdsa-with-SHA384                            |
   |       | OID:         1.2.840.10045.4.3.3                          |
   |       | Parameters:  Absent                                       |
   |       | DER:         30 0A 06 08 2A 86 48 CE 3D 04 03 03          |
   |       | Comments:    See Section 3.2.2.                           |
   +-------+-----------------------------------------------------------+
   |     2 | Name:        ECDSA with SHA-512                           |
   |       | Identifiers: ecdsa-with-SHA512                            |
   |       | OID:         1.2.840.10045.4.3.4                          |
   |       | Parameters:  Absent                                       |
   |       | DER:         30 0A 06 08 2A 86 48 CE 3D 04 03 04          |
   |       | Comments:    See Section 3.2.2.                           |
   +-------+-----------------------------------------------------------+
   |     3 | Name:        ECDSA with SHAKE128                          |
   |       | Identifiers: id-ecdsa-with-shake128                       |
   |       | OID:         1.3.6.1.5.5.7.6.32                           |
   |       | Parameters:  Absent                                       |
   |       | DER:         30 0A 06 08 2B 06 01 05 05 07 06 20          |
   |       | Comments:    See Section 3.2.2.                           |
   +-------+-----------------------------------------------------------+
   |     4 | Name:        ECDSA with SHAKE256                          |
   |       | Identifiers: id-ecdsa-with-shake256                       |
   |       | OID:         1.3.6.1.5.5.7.6.33                           |
   |       | Parameters:  Absent                                       |
   |       | DER:         30 0A 06 08 2B 06 01 05 05 07 06 21          |
   |       | Comments:    See Section 3.2.2.                           |
   +-------+-----------------------------------------------------------+
   |     5 | Name:        Unsigned                                     |
   |       | Identifiers: id-alg-unsigned                              |
   |       | OID:         1.3.6.1.5.5.7.6.36                           |
   |       | Parameters:  Absent                                       |
   |       | DER:         30 0A 06 08 2B 06 01 05 05 07 06 24          |
   |       | Comments:    bytes of size 0                              |
   +-------+-----------------------------------------------------------+
   |     8 | Name:        SM2 with SM3                                 |
   |       | Identifiers: sm2-with-sm3                                 |
   |       | OID:         1.2.156.10197.1.501                          |
   |       | Parameters:  Absent                                       |
   |       | DER:         30 0A 06 08 2A 81 1C CF 55 01 83 75          |
   |       | Comments:    See Section 3.2.2.                           |
   +-------+-----------------------------------------------------------+
   |    12 | Name:        Ed25519                                      |
   |       | Identifiers: id-Ed25519, id-EdDSA25519                    |
   |       | OID:         1.3.101.112                                  |



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   |       | Parameters:  Absent                                       |
   |       | DER:         30 05 06 03 2B 65 70                         |
   |       | Comments:                                                 |
   +-------+-----------------------------------------------------------+
   |    13 | Name:        Ed448                                        |
   |       | Identifiers: id-Ed448, id-EdDSA448                        |
   |       | OID:         1.3.101.113                                  |
   |       | Parameters:  Absent                                       |
   |       | DER:         30 05 06 03 2B 65 71                         |
   |       | Comments:                                                 |
   +-------+-----------------------------------------------------------+
   |    14 | Name:        PoP with SHA-256 and HMAC-SHA256             |
   |       | Identifiers: sa-ecdhPop-sha256-hmac-sha256                |
   |       | OID:         1.3.6.1.5.5.7.6.26                           |
   |       | Parameters:  Absent                                       |
   |       | DER:         30 0A 06 08 2B 06 01 05 05 07 06 1A          |
   |       | Comments:    Proof-of-possession algorithm, indexed with  |
   |       |              KDF and MAC, see RFC 6955. Requires          |
   |       |              recipient's public static Diffie-Hellman key |
   +-------+-----------------------------------------------------------+
   |    15 | Name:        PoP with SHA-384 and HMAC-SHA384             |
   |       | Identifiers: sa-ecdhPop-sha384-hmac-sha384                |
   |       | OID:         1.3.6.1.5.5.7.6.27                           |
   |       | Parameters:  Absent                                       |
   |       | DER:         30 0A 06 08 2B 06 01 05 05 07 06 1B          |
   |       | Comments:    Proof-of-possession algorithm, indexed with  |
   |       |              KDF and MAC, see RFC 6955. Requires          |
   |       |              recipient's public static Diffie-Hellman key |
   +-------+-----------------------------------------------------------+
   |    16 | Name:        PoP with SHA-512 and HMAC-SHA512             |
   |       | Identifiers: sa-ecdhPop-sha512-hmac-sha512                |
   |       | OID:         1.3.6.1.5.5.7.6.28                           |
   |       | Parameters:  Absent                                       |
   |       | DER:         30 0A 06 08 2B 06 01 05 05 07 06 1C          |
   |       | Comments:    Proof-of-possession algorithm, indexed with  |
   |       |              KDF and MAC, see RFC 6955. Requires          |
   |       |              recipient's public static Diffie-Hellman key |
   +-------+-----------------------------------------------------------+
   |    23 | Name:        RSASSA-PKCS1-v1_5 with SHA-256               |
   |       | Identifiers: sha256WithRSAEncryption                      |
   |       | OID:         1.2.840.113549.1.1.11                        |
   |       | Parameters:  NULL                                         |
   |       | DER:         30 0B 06 09 2A 86 48 86 F7 0D 01 01 0B 05 00 |
   |       | Comments:                                                 |
   +-------+-----------------------------------------------------------+
   |    24 | Name:        RSASSA-PKCS1-v1_5 with SHA-384               |
   |       | Identifiers: sha384WithRSAEncryption                      |
   |       | OID:         1.2.840.113549.1.1.12                        |



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   |       | Parameters:  NULL                                         |
   |       | DER:         30 0B 06 09 2A 86 48 86 F7 0D 01 01 0C 05 00 |
   |       | Comments:                                                 |
   +-------+-----------------------------------------------------------+
   |    25 | Name:        RSASSA-PKCS1-v1_5 with SHA-512               |
   |       | Identifiers: sha512WithRSAEncryption                      |
   |       | OID:         1.2.840.113549.1.1.13                        |
   |       | Parameters:  NULL                                         |
   |       | DER:         30 0B 06 09 2A 86 48 86 F7 0D 01 01 0D 05 00 |
   |       | Comments:                                                 |
   +-------+-----------------------------------------------------------+
   |    26 | Name:        RSASSA-PSS with SHA-256                      |
   |       | Identifiers: rsassa-pss, id-RSASSA-PSS                    |
   |       | OID:         1.2.840.113549.1.1.10                        |
   |       | Parameters:  SHA-256, MGF-1 with SHA-256, saltLength = 32 |
   |       | DER:         30 41 06 09 2A 86 48 86 F7 0D 01 01 0A 30 34 |
   |       |              A0 0F 30 0D 06 09 60 86 48 01 65 03 04 02 01 |
   |       |              05 00 A1 1C 30 1A 06 09 2A 86 48 86 F7 0D 01 |
   |       |              01 08 30 0D 06 09 60 86 48 01 65 03 04 02 01 |
   |       |              05 00 A2 03 02 01 20                         |
   |       | Comments:                                                 |
   +-------+-----------------------------------------------------------+
   |    27 | Name:        RSASSA-PSS with SHA-384                      |
   |       | Identifiers: rsassa-pss, id-RSASSA-PSS                    |
   |       | OID:         1.2.840.113549.1.1.10                        |
   |       | Parameters:  SHA-384, MGF-1 with SHA-384, saltLength = 48 |
   |       | DER:         30 41 06 09 2A 86 48 86 F7 0D 01 01 0A 30 34 |
   |       |              A0 0F 30 0D 06 09 60 86 48 01 65 03 04 02 02 |
   |       |              05 00 A1 1C 30 1A 06 09 2A 86 48 86 F7 0D 01 |
   |       |              01 08 30 0D 06 09 60 86 48 01 65 03 04 02 02 |
   |       |              05 00 A2 03 02 01 30                         |
   |       | Comments:                                                 |
   +-------+-----------------------------------------------------------+
   |    28 | Name:        RSASSA-PSS with SHA-512                      |
   |       | Identifiers: rsassa-pss, id-RSASSA-PSS                    |
   |       | OID:         1.2.840.113549.1.1.10                        |
   |       | Parameters:  SHA-512, MGF-1 with SHA-512, saltLength = 64 |
   |       | DER:         30 41 06 09 2A 86 48 86 F7 0D 01 01 0A 30 34 |
   |       |              A0 0F 30 0D 06 09 60 86 48 01 65 03 04 02 03 |
   |       |              05 00 A1 1C 30 1A 06 09 2A 86 48 86 F7 0D 01 |
   |       |              01 08 30 0D 06 09 60 86 48 01 65 03 04 02 03 |
   |       |              05 00 A2 03 02 01 40                         |
   |       | Comments:                                                 |
   +-------+-----------------------------------------------------------+
   |    29 | Name:        RSASSA-PSS with SHAKE128                     |
   |       | Identifiers: id-RSASSA-PSS-SHAKE128                       |
   |       | OID:         1.3.6.1.5.5.7.6.30                           |
   |       | Parameters:  Absent                                       |



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   |       | DER:         30 0A 06 08 2B 06 01 05 05 07 06 1E          |
   |       | Comments:                                                 |
   +-------+-----------------------------------------------------------+
   |    30 | Name:        RSASSA-PSS with SHAKE256                     |
   |       | Identifiers: id-RSASSA-PSS-SHAKE256                       |
   |       | OID:         1.3.6.1.5.5.7.6.31                           |
   |       | Parameters:  Absent                                       |
   |       | DER:         30 0A 06 08 2B 06 01 05 05 07 06 1F          |
   |       | Comments:                                                 |
   +-------+-----------------------------------------------------------+

                    Figure 18: C509 Signature Algorithms

8.15.  C509 Public Key Algorithms Registry

   IANA has created a new registry titled "C509 Public Key Algorithms"
   under the registry group "CBOR Encoded X.509 (C509)".  The fields of
   the registry are Value, Name, Identifiers, OID, Parameters, DER,
   Comments, and Reference, where Value is an integer, and the other
   columns are text strings.  The fields Name, OID, Parameters, and DER
   are mandatory.  If the public key can only be used with one signature
   algorithm and the OID of the public key algorithm is the same as the
   signature algorithm, then the value must be chosen equal to the value
   of signature algorithm, see Section 8.14.  If it is not expected to
   be understood from the other information (e.g. the OID), then the
   Comments field must contain a reference to where the Public Key
   Algorithm is described.  For values in the interval [-24, 23] the
   registration procedure is "IETF Review with Expert Review".  For all
   other values the registration procedure is "Expert Review".  The
   initial contents of the registry are:

   +-------+-----------------------------------------------------------+
   | Value | Public Key Algorithm                                      |
   +=======+===========================================================+
   |     0 | Name:        RSA                                          |
   |       | Identifiers: rsaEncryption                                |
   |       | OID:         1.2.840.113549.1.1.1                         |
   |       | Parameters:  NULL                                         |
   |       | DER:         30 0D 06 09 2A 86 48 86 F7 0D 01 01 01 05 00 |
   |       | Comments:    subjectPublicKey encoded as in Section 3.2.1 |
   +-------+-----------------------------------------------------------+
   |     1 | Name:        EC Public Key (Weierstrass) with secp256r1   |
   |       | Identifiers: ecPublicKey, id-ecPublicKey                  |
   |       | OID:         1.2.840.10045.2.1                            |
   |       | Parameters:  namedCurve = secp256r1 (1.2.840.10045.3.1.7) |
   |       | DER:         30 13 06 07 2A 86 48 CE 3D 02 01 06 08 2A 86 |
   |       |              48 CE 3D 03 01 07                            |
   |       | Comments:    subjectPublicKey encoded as in Section 3.2.1 |



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   |       |              Also known as P-256, ansip256r1, prime256v1  |
   +-------+-----------------------------------------------------------+
   |     2 | Name:        EC Public Key (Weierstrass) with secp384r1   |
   |       | Identifiers: ecPublicKey, id-ecPublicKey                  |
   |       | OID:         1.2.840.10045.2.1                            |
   |       | Parameters:  namedCurve = secp384r1 (1.3.132.0.34)        |
   |       | DER:         30 10 06 07 2A 86 48 CE 3D 02 01 06 05 2B 81 |
   |       |              04 00 22                                     |
   |       | Comments:    subjectPublicKey encoded as in Section 3.2.1 |
   |       |              Also known as P-384, ansip384r1              |
   +-------+-----------------------------------------------------------+
   |     3 | Name:        EC Public Key (Weierstrass) with secp521r1   |
   |       | Identifiers: ecPublicKey, id-ecPublicKey                  |
   |       | OID:         1.2.840.10045.2.1                            |
   |       | Parameters:  namedCurve = secp521r1 (1.3.132.0.35)        |
   |       | DER:         30 10 06 07 2A 86 48 CE 3D 02 01 06 05 2B 81 |
   |       |              04 00 23                                     |
   |       | Comments:    subjectPublicKey encoded as in Section 3.2.1 |
   |       |              Also known as P-521, ansip521r1              |
   +-------+-----------------------------------------------------------+
   |     6 | Name:        EC Public Key (Weierstrass) with             |
   |       |              sm2p256v1                                    |
   |       | Identifiers: ecPublicKey, id-ecPublicKey                  |
   |       | OID:         1.2.840.10045.2.1                            |
   |       | Parameters:  namedCurve = sm2p256v1                       |
   |       |              (1.2.156.10197.1.301)                        |
   |       | DER:         30 13 06 07 2A 86 48 CE 3D 02 01 06 08 2A 81 |
   |       |              1C CF 55 01 82 2D                            |
   |       | Comments:    subjectPublicKey encoded as in Section 3.2.1 |
   +-------+-----------------------------------------------------------+
   |     8 | Name:        X25519 (Montgomery)                          |
   |       | Identifiers: id-X25519                                    |
   |       | OID:         1.3.101.110                                  |
   |       | Parameters:  Absent                                       |
   |       | DER:         30 05 06 03 2B 65 6E                         |
   |       | Comments:                                                 |
   +-------+-----------------------------------------------------------+
   |     9 | Name:        X448 (Montgomery)                            |
   |       | Identifiers: id-X448                                      |
   |       | OID:         1.3.101.111                                  |
   |       | Parameters:  Absent                                       |
   |       | DER:         30 05 06 03 2B 65 6F                         |
   |       | Comments:                                                 |
   +-------+-----------------------------------------------------------+
   |    12 | Name:        Ed25519 (Twisted Edwards)                    |
   |       | Identifiers: id-Ed25519, id-EdDSA25519                    |
   |       | OID:         1.3.101.112                                  |
   |       | Parameters:  Absent                                       |



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   |       | DER:         30 05 06 03 2B 65 70                         |
   |       | Comments:                                                 |
   +-------+-----------------------------------------------------------+
   |    13 | Name:        Ed448 (Edwards)                              |
   |       | Identifiers: id-Ed448, id-EdDSA448                        |
   |       | OID:         1.3.101.113                                  |
   |       | Parameters:  Absent                                       |
   |       | DER:         30 05 06 03 2B 65 71                         |
   |       | Comments:                                                 |
   +-------+-----------------------------------------------------------+
   |    24 | Name:        EC Public Key (Weierstrass) with             |
   |       |              brainpoolP256r1                              |
   |       | Identifiers: ecPublicKey, id-ecPublicKey                  |
   |       | OID:         1.2.840.10045.2.1                            |
   |       | Parameters:  namedCurve = brainpoolP256r1                 |
   |       |              (1.3.36.3.3.2.8.1.1.7)                       |
   |       | DER:         30 14 06 07 2A 86 48 CE 3D 02 01 06 09 2B 24 |
   |       |              03 03 02 08 01 01 07                         |
   |       | Comments:    subjectPublicKey encoded as in Section 3.2.1 |
   +-------+-----------------------------------------------------------+
   |    25 | Name:        EC Public Key (Weierstrass) with             |
   |       |              brainpoolP384r1                              |
   |       | Identifiers: ecPublicKey, id-ecPublicKey                  |
   |       | OID:         1.2.840.10045.2.1                            |
   |       | Parameters:  namedCurve = brainpoolP384r1                 |
   |       |              (1.3.36.3.3.2.8.1.1.11)                      |
   |       | DER:         30 14 06 07 2A 86 48 CE 3D 02 01 06 09 2B 24 |
   |       |              03 03 02 08 01 01 0B                         |
   |       | Comments:    subjectPublicKey encoded as in Section 3.2.1 |
   +-------+-----------------------------------------------------------+
   |    26 | Name:        EC Public Key (Weierstrass) with             |
   |       |              brainpoolP512r1                              |
   |       | Identifiers: ecPublicKey, id-ecPublicKey                  |
   |       | OID:         1.2.840.10045.2.1                            |
   |       | Parameters:  namedCurve = brainpoolP512r1                 |
   |       |              (1.3.36.3.3.2.8.1.1.13)                      |
   |       | DER:         30 14 06 07 2A 86 48 CE 3D 02 01 06 09 2B 24 |
   |       |              03 03 02 08 01 01 0D                         |
   |       | Comments:    subjectPublicKey encoded as in Section 3.2.1 |
   +-------+-----------------------------------------------------------+
   |    27 | Name:        EC Public Key (Weierstrass) with             |
   |       |              FRP256v1                                     |
   |       | Identifiers: ecPublicKey, id-ecPublicKey                  |
   |       | OID:         1.2.840.10045.2.1                            |
   |       | Parameters:  namedCurve = FRP256v1                        |
   |       |              (1.2.250.1.223.101.256.1)                    |
   |       | DER:         30 15 06 07 2A 86 48 CE 3D 02 01 06 0A 2A 81 |
   |       |              7A 01 81 5F 65 82 00 01                      |



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   |       | Comments:    subjectPublicKey encoded as in Section 3.2.1 |
   +-------+-----------------------------------------------------------+

                   Figure 19: C509 Public Key Algorithms

8.16.  COSE Header Parameters Registry

   IANA is requested to assign the entries in Table 1 to the "COSE
   Header Parameters" registry in the registry group "CBOR Object
   Signing and Encryption (COSE)" with this document as reference.

8.17.  COSE Header Algorithm Parameters Registry

   IANA is requested to assign the entries in Table 2 to the "COSE
   Header Algorithm Parameters" registry in the registry group "CBOR
   Object Signing and Encryption (COSE)" with this document as
   reference.

8.18.  Media Type Application Registry

   IANA is requested to assign the following entries into the
   "application" registry in the registry group "Media Types" with this
   document as reference.

8.18.1.  Media Type application/cose-c509-cert

   When the application/cose-c509-cert media type is used, the data is a
   COSE_C509 structure.  If the parameter "usage" is set to "chain",
   this sequence indicates a certificate chain.

   Type name: application

   Subtype name: cose-c509-cert

   Required parameters: N/A

   Optional parameters: usage

   *  Can be absent to provide no further information about the intended
      meaning of the order in the CBOR sequence of certificates.

   *  Can be set to "chain" to indicate that the sequence of data items
      is to be interpreted as a certificate chain.

   Encoding considerations: binary

   Security considerations: See the Security Considerations section of
   [[this document]].



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   Interoperability considerations: N/A

   Published specification: [[this document]]

   Applications that use this media type: Applications that employ COSE
   and use C509 as a certificate type.

   Fragment identifier considerations: N/A

   Additional information:

   *  Deprecated alias names for this type: N/A

   *  Magic number(s): TBD8, TBD6

   *  File extension(s): .c509

   *  Macintosh file type code(s): N/A

   Person & email address to contact for further information:
   iesg@ietf.org

   Intended usage: COMMON

   Restrictions on usage: N/A

   Author: COSE WG

   Change controller: IETF

8.18.2.  Media Type application/cose-c509-pkcs10

   When the application/cose-c509-pkcs10 media type is used, the data is
   a C509CertificationRequest structure.

   Type name: application

   Subtype name: cose-c509-pkcs10

   Required parameters: N/A

   Optional parameters: N/A

   Encoding considerations: binary

   Security considerations: See the Security Considerations section of
   [[this document]].




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   Interoperability considerations: N/A

   Published specification: [[this document]]

   Applications that use this media type: Applications that employ COSE
   and C509 Certification Request.

   Fragment identifier considerations: N/A

   Additional information:

   *  Deprecated alias names for this type: N/A

   *  Magic number(s): TBD9

   *  File extension(s): .c509

   *  Macintosh file type code(s): N/A

   Person & email address to contact for further information:
   iesg@ietf.org

   Intended usage: COMMON

   Restrictions on usage: N/A

   Author: COSE WG

   Change controller: IETF

8.18.3.  Media Type application/cose-c509-crtemplate

   When the application/cose-c509-crtemplate media type is used, the
   data is a C509CertificationRequestTemplate structure.

   Type name: application

   Subtype name: cose-c509-crtemplate

   Required parameters: N/A

   Optional parameters: N/A

   Encoding considerations: binary

   Security considerations: See the Security Considerations section of
   [[this document]].




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   Interoperability considerations: N/A

   Published specification: [[this document]]

   Applications that use this media type: Applications that employ COSE
   and C509 Certification Request.

   Fragment identifier considerations: N/A

   Additional information:

   *  Deprecated alias names for this type: N/A

   *  Magic number(s): TBD18

   *  File extension(s): .c509

   *  Macintosh file type code(s): N/A

   Person & email address to contact for further information:
   iesg@ietf.org

   Intended usage: COMMON

   Restrictions on usage: N/A

   Author: COSE WG

   Change controller: IETF

8.18.4.  Media Type application/cose-c509-privkey

   When the application/cose-c509-privkey media type is used, the data
   is a C509PrivateKey structure.

   Type name: application

   Subtype name: cose-c509-privkey

   Required parameters: N/A

   Optional parameters: N/A

   Encoding considerations: binary

   Security considerations: See the Security Considerations section of
   [[this document]].




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   Interoperability considerations: N/A

   Published specification: [[this document]]

   Applications that use this media type: Applications that employ COSE
   and use C509 as a certificate type.

   Fragment identifier considerations: N/A

   Additional information:

   *  Deprecated alias names for this type: N/A

   *  Magic number(s): TBD12

   *  File extension(s): .c509

   *  Macintosh file type code(s): N/A

   Person & email address to contact for further information:
   iesg@ietf.org

   Intended usage: COMMON

   Restrictions on usage: N/A

   Author: COSE WG

   Change controller: IETF

8.18.5.  Media Type application/cose-c509-pem

   When the application/cose-c509-pem media type is used, the data is a
   C509PEM structure.

   Type name: application

   Subtype name: cose-c509-pem

   Required parameters: N/A

   Optional parameters: N/A

   Encoding considerations: binary

   Security considerations: See the Security Considerations section of
   [[this document]].




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   Interoperability considerations: N/A

   Published specification: [[this document]]

   Applications that use this media type: Applications that employ COSE
   and use C509 as a certificate type.

   Fragment identifier considerations: N/A

   Additional information:

   *  Deprecated alias names for this type: N/A

   *  Magic number(s): TBD13

   *  File extension(s): .c509

   *  Macintosh file type code(s): N/A

   Person & email address to contact for further information:
   iesg@ietf.org

   Intended usage: COMMON

   Restrictions on usage: N/A

   Author: COSE WG

   Change controller: IETF

8.18.6.  Media Type application/cose-certhash

   When the application/cose-certhash media type is used, the data is a
   COSE_CertHash structure as defined in [RFC9360].  If the parameter
   "usage" is set to "c509", the hash value is calculated over a C509
   certificate.

   Type name: application

   Subtype name: cose-certhash

   Required parameters: N/A

   Optional parameters: usage

   *  Can be absent to provide no further information about what the
      hash value is calculated over.




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   *  Can be set to "c509" to indicate that the COSE_CertHash structure
      as defined in [RFC9360] is used, with hashValue calculated over a
      C509 certificate as defined in Section 3.4.

   Encoding considerations: binary

   Security considerations: See the Security Considerations section of
   [RFC9360].

   Interoperability considerations: N/A

   Published specification: [[this document]]

   Applications that use this media type: Applications that employ COSE
   and use X.509 or C509 as certificate type.

   Fragment identifier considerations: N/A

   Additional information:

   *  Deprecated alias names for this type: N/A

   *  Magic number(s): N/A

   *  File extension(s): N/A

   *  Macintosh file type code(s): N/A

   Person & email address to contact for further information:
   iesg@ietf.org

   Intended usage: COMMON

   Restrictions on usage: N/A

   Author: COSE WG

   Change controller: IETF

8.19.  CoAP Content-Formats Registry

   IANA is requested to add entries for "application/cose-c509-cert",
   "application/cose-c509-pkcs10", "application/cose-c509-crtemplate",
   "application/cose-c509-privkey" and "application/cose-c509-pem" to
   the "CoAP Content-Formats" registry in the registry group
   "Constrained RESTful Environments (CoRE) Parameters".  A dedicated
   Content-Format ID is requested for the "application/cose-c509-cert"
   media type in the case when the parameter "usage" is set to "chain",



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   see Section 8.18.1.

   IANA is requested to add entries for "application/cose-certhash" to
   the "CoAP Content-Formats" registry in the registry group
   "Constrained RESTful Environments (CoRE) Parameters".  A dedicated
   Content-Format ID is requested in the case when the parameter "usage"
   is set to "c509", see Section 8.18.6.

   IANA is requested to add entries for "application/cbor" to the "CoAP
   Content-Formats" registry in the registry group "Constrained RESTful
   Environments (CoRE) Parameters", in the case when the encoding is a
   CBOR text string containing a URI, see [RFC3986].

   +----------------------+---------+-----------+-------+------------+
   | Content              | Content | Media     | ID    | Reference  |
   | Format               | Coding  | Type      |       |            |
   +======================+=========+===========+=======+============+
   | application/         | -       | [[link    | TBD3  | [[this     |
   | cose-c509-cert       |         | to 8.18]] |       | document]] |
   +----------------------+---------+-----------+-------+------------+
   | application/         |         | [[link    |       | [[this     |
   | cose-c509-cert;      | -       | to 8.18]] | TBD15 | document]] |
   | usage=chain          |         |           |       |            |
   +----------------------+---------+-----------+-------+------------+
   | application/         | -       | [[link    | TBD4  | [[this     |
   | cose-c509-pkcs10     |         | to 8.18]] |       | document]] |
   +----------------------+---------+-----------+-------+------------+
   | application/         | -       | [[link    | TBD19 | [[this     |
   | cose-c509-crtemplate |         | to 8.18]] |       | document]] |
   +----------------------+---------+-----------+-------+------------+
   | application/         | -       | [[link    | TBD10 | [[this     |
   | cose-c509-privkey    |         | to 8.18]] |       | document]] |
   +----------------------+---------+-----------+-------+------------+
   | application/         | -       | [[link    | TBD11 | [[this     |
   | cose-c509-pem        |         | to 8.18]] |       | document]] |
   +----------------------+---------+-----------+-------+------------+
   | application/         | -       | [[link    | TBD16 | [[this     |
   | cose-certhash        |         | to 8.18]] |       | document]] |
   +----------------------+---------+-----------+-------+------------+
   | application/         |         | [[link    |       | [[this     |
   | cose-certhash;       | -       | to 8.18]] | TBD17 | document]] |
   | usage=c509           |         |           |       |            |
   +----------------------+---------+-----------+-------+------------+

                     Figure 20: CoAP Content-Format IDs






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8.20.  TLS Certificate Types Registry

   This document registers the following entry in the "TLS Certificate
   Types" registry in the registry group "Transport Layer Security (TLS)
   Extensions".  The new certificate type can be used with additional
   TLS certificate compression [RFC8879].  For TLS 1.3, the C509
   certificate type is defined as a new case in the CertificateEntry
   struct specified in Section 4.4.2 of [RFC8446]:

   case C509:
     opaque c509_data<1..2^24-1>;

   where c509_data is the CBOR sequence ~C509Certificate (an unwrapped
   C509Certificate).  For TLS 1.2 the same construction is applied with
   a similar union type defined for the Certificate struct in
   Section 7.4.2 of [RFC5246].  Note that, similar to COSE_C509, the TLS
   handshake contains the length of each certificate.  The TLS
   extensions client_certificate_type and server_certificate_type
   [RFC7250] are used to negotiate the use of C509.

   +-------+------------------+-------------+--------------------------+
   | Value | Name             | Recommended | Comment                  |
   +=======+==================+=============+==========================+
   |  TBD5 | C509 Certificate |           N |                          |
   +-------+------------------+-------------+--------------------------+

8.21.  TLSA Selectors Registry

   This document registers the following entry in the "TLSA Selectors"
   registry in the registry group "DNS-Based Authentication of Named
   Entities (DANE) Parameters".  The C509 certificate data,
   C509CertData, is defined in Section 3.4.

   +-------+---------+------------------------+-------------------+
   | Value | Acronym |   Short Description    |     Reference     |
   +=======+=========+========================+===================+
   |  TBD7 |    C509 | C509 certificate data  | [[this document]] |
   +-------+---------+------------------------+-------------------+

   The TLSA selectors registry defined in [RFC6698] originally only
   applied to PKIX [RFC5280] certificates in DER encoding.  This
   specification updates [RFC6698] to accept the use of C509
   certificates.








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8.22.  EDHOC Authentication Credential Types Registry

   This document registers the following entry in the "EDHOC
   Authentication Credential Types" registry in the registry group
   "Ephemeral Diffie-Hellman Over COSE (EDHOC)".  This is useful to
   identify C509 certificates as a supported authentication credential
   type to use with EDHOC [RFC9528], for example, during discovery of
   EDHOC resources, see [RFC9668].

   +-------+----------------------+-------------------+
   | Value | Description          |     Reference     |
   +=======+======================+===================+
   |   3   | C509 certificate     | [[this document]] |
   +-------+----------------------+-------------------+

8.23.  Relative Distinguished Name Attribute

   This document registers the following entry in the "SMI Security for
   PKIX Relative Distinguished Name Attribute" registry [RFC7299]:

   +---------+----------------------+-------------------+
   | Decimal | Description          |     Reference     |
   +=========+======================+===================+
   | TBD30   | id-rdna-c509Name     | [[this document]] |
   +---------+----------------------+-------------------+

9.  References

9.1.  Normative References

   [I-D.ietf-lamps-macaddress-on]
              Housley, R., Bonnell, C., Mandel, J., Okubo, T., and M.
              StJohns, "Media Access Control (MAC) Addresses in X.509
              Certificates", Work in Progress, Internet-Draft, draft-
              ietf-lamps-macaddress-on-07, 12 March 2026,
              <https://datatracker.ietf.org/doc/html/draft-ietf-lamps-
              macaddress-on-07>.

   [POSIX]    "IEEE Standard for Information Technology--Portable
              Operating System Interface (POSIX(TM)) Base
              Specifications, Issue 7", January 2018,
              <https://pubs.opengroup.org/onlinepubs/9699919799/>.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/rfc/rfc2119>.




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   [RFC2985]  Nystrom, M. and B. Kaliski, "PKCS #9: Selected Object
              Classes and Attribute Types Version 2.0", RFC 2985,
              DOI 10.17487/RFC2985, November 2000,
              <https://www.rfc-editor.org/rfc/rfc2985>.

   [RFC2986]  Nystrom, M. and B. Kaliski, "PKCS #10: Certification
              Request Syntax Specification Version 1.7", RFC 2986,
              DOI 10.17487/RFC2986, November 2000,
              <https://www.rfc-editor.org/rfc/rfc2986>.

   [RFC3779]  Lynn, C., Kent, S., and K. Seo, "X.509 Extensions for IP
              Addresses and AS Identifiers", RFC 3779,
              DOI 10.17487/RFC3779, June 2004,
              <https://www.rfc-editor.org/rfc/rfc3779>.

   [RFC3986]  Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
              Resource Identifier (URI): Generic Syntax", STD 66,
              RFC 3986, DOI 10.17487/RFC3986, January 2005,
              <https://www.rfc-editor.org/rfc/rfc3986>.

   [RFC4108]  Housley, R., "Using Cryptographic Message Syntax (CMS) to
              Protect Firmware Packages", RFC 4108,
              DOI 10.17487/RFC4108, August 2005,
              <https://www.rfc-editor.org/rfc/rfc4108>.

   [RFC5246]  Dierks, T. and E. Rescorla, "The Transport Layer Security
              (TLS) Protocol Version 1.2", RFC 5246,
              DOI 10.17487/RFC5246, August 2008,
              <https://www.rfc-editor.org/rfc/rfc5246>.

   [RFC5280]  Cooper, D., Santesson, S., Farrell, S., Boeyen, S.,
              Housley, R., and W. Polk, "Internet X.509 Public Key
              Infrastructure Certificate and Certificate Revocation List
              (CRL) Profile", RFC 5280, DOI 10.17487/RFC5280, May 2008,
              <https://www.rfc-editor.org/rfc/rfc5280>.

   [RFC5958]  Turner, S., "Asymmetric Key Packages", RFC 5958,
              DOI 10.17487/RFC5958, August 2010,
              <https://www.rfc-editor.org/rfc/rfc5958>.

   [RFC6066]  Eastlake 3rd, D., "Transport Layer Security (TLS)
              Extensions: Extension Definitions", RFC 6066,
              DOI 10.17487/RFC6066, January 2011,
              <https://www.rfc-editor.org/rfc/rfc6066>.







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   [RFC6698]  Hoffman, P. and J. Schlyter, "The DNS-Based Authentication
              of Named Entities (DANE) Transport Layer Security (TLS)
              Protocol: TLSA", RFC 6698, DOI 10.17487/RFC6698, August
              2012, <https://www.rfc-editor.org/rfc/rfc6698>.

   [RFC7030]  Pritikin, M., Ed., Yee, P., Ed., and D. Harkins, Ed.,
              "Enrollment over Secure Transport", RFC 7030,
              DOI 10.17487/RFC7030, October 2013,
              <https://www.rfc-editor.org/rfc/rfc7030>.

   [RFC7120]  Cotton, M., "Early IANA Allocation of Standards Track Code
              Points", BCP 100, RFC 7120, DOI 10.17487/RFC7120, January
              2014, <https://www.rfc-editor.org/rfc/rfc7120>.

   [RFC7250]  Wouters, P., Ed., Tschofenig, H., Ed., Gilmore, J.,
              Weiler, S., and T. Kivinen, "Using Raw Public Keys in
              Transport Layer Security (TLS) and Datagram Transport
              Layer Security (DTLS)", RFC 7250, DOI 10.17487/RFC7250,
              June 2014, <https://www.rfc-editor.org/rfc/rfc7250>.

   [RFC7299]  Housley, R., "Object Identifier Registry for the PKIX
              Working Group", RFC 7299, DOI 10.17487/RFC7299, July 2014,
              <https://www.rfc-editor.org/rfc/rfc7299>.

   [RFC8126]  Cotton, M., Leiba, B., and T. Narten, "Guidelines for
              Writing an IANA Considerations Section in RFCs", BCP 26,
              RFC 8126, DOI 10.17487/RFC8126, June 2017,
              <https://www.rfc-editor.org/rfc/rfc8126>.

   [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
              2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
              May 2017, <https://www.rfc-editor.org/rfc/rfc8174>.

   [RFC8295]  Turner, S., "EST (Enrollment over Secure Transport)
              Extensions", RFC 8295, DOI 10.17487/RFC8295, January 2018,
              <https://www.rfc-editor.org/rfc/rfc8295>.

   [RFC8360]  Huston, G., Michaelson, G., Martinez, C., Bruijnzeels, T.,
              Newton, A., and D. Shaw, "Resource Public Key
              Infrastructure (RPKI) Validation Reconsidered", RFC 8360,
              DOI 10.17487/RFC8360, April 2018,
              <https://www.rfc-editor.org/rfc/rfc8360>.

   [RFC8610]  Birkholz, H., Vigano, C., and C. Bormann, "Concise Data
              Definition Language (CDDL): A Notational Convention to
              Express Concise Binary Object Representation (CBOR) and
              JSON Data Structures", RFC 8610, DOI 10.17487/RFC8610,
              June 2019, <https://www.rfc-editor.org/rfc/rfc8610>.



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   [RFC8742]  Bormann, C., "Concise Binary Object Representation (CBOR)
              Sequences", RFC 8742, DOI 10.17487/RFC8742, February 2020,
              <https://www.rfc-editor.org/rfc/rfc8742>.

   [RFC8949]  Bormann, C. and P. Hoffman, "Concise Binary Object
              Representation (CBOR)", STD 94, RFC 8949,
              DOI 10.17487/RFC8949, December 2020,
              <https://www.rfc-editor.org/rfc/rfc8949>.

   [RFC9052]  Schaad, J., "CBOR Object Signing and Encryption (COSE):
              Structures and Process", STD 96, RFC 9052,
              DOI 10.17487/RFC9052, August 2022,
              <https://www.rfc-editor.org/rfc/rfc9052>.

   [RFC9053]  Schaad, J., "CBOR Object Signing and Encryption (COSE):
              Initial Algorithms", RFC 9053, DOI 10.17487/RFC9053,
              August 2022, <https://www.rfc-editor.org/rfc/rfc9053>.

   [RFC9090]  Bormann, C., "Concise Binary Object Representation (CBOR)
              Tags for Object Identifiers", RFC 9090,
              DOI 10.17487/RFC9090, July 2021,
              <https://www.rfc-editor.org/rfc/rfc9090>.

   [RFC9277]  Richardson, M. and C. Bormann, "On Stable Storage for
              Items in Concise Binary Object Representation (CBOR)",
              RFC 9277, DOI 10.17487/RFC9277, August 2022,
              <https://www.rfc-editor.org/rfc/rfc9277>.

   [RFC9360]  Schaad, J., "CBOR Object Signing and Encryption (COSE):
              Header Parameters for Carrying and Referencing X.509
              Certificates", RFC 9360, DOI 10.17487/RFC9360, February
              2023, <https://www.rfc-editor.org/rfc/rfc9360>.

   [RFC9542]  Eastlake 3rd, D., Abley, J., and Y. Li, "IANA
              Considerations and IETF Protocol and Documentation Usage
              for IEEE 802 Parameters", BCP 141, RFC 9542,
              DOI 10.17487/RFC9542, April 2024,
              <https://www.rfc-editor.org/rfc/rfc9542>.

   [RFC9549]  Housley, R., "Internationalization Updates to RFC 5280",
              RFC 9549, DOI 10.17487/RFC9549, March 2024,
              <https://www.rfc-editor.org/rfc/rfc9549>.

   [RFC9598]  Melnikov, A., Chuang, W., and C. Bonnell,
              "Internationalized Email Addresses in X.509 Certificates",
              RFC 9598, DOI 10.17487/RFC9598, May 2024,
              <https://www.rfc-editor.org/rfc/rfc9598>.




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   [RFC9668]  Palombini, F., Tiloca, M., Höglund, R., Hristozov, S., and
              G. Selander, "Using Ephemeral Diffie-Hellman Over COSE
              (EDHOC) with the Constrained Application Protocol (CoAP)
              and Object Security for Constrained RESTful Environments
              (OSCORE)", RFC 9668, DOI 10.17487/RFC9668, November 2024,
              <https://www.rfc-editor.org/rfc/rfc9668>.

   [RFC9883]  Housley, R., "An Attribute for Statement of Possession of
              a Private Key", RFC 9883, DOI 10.17487/RFC9883, October
              2025, <https://www.rfc-editor.org/rfc/rfc9883>.

   [SECG]     "Elliptic Curve Cryptography, Standards for Efficient
              Cryptography Group, ver. 2", 2009,
              <https://secg.org/sec1-v2.pdf>.

   [Wi-SUN]   "Wi-SUN Alliance", n.d., <https://wi-sun.org>.

   [X.501]    "Information Technology - Open Systems Interconnection -
              The Directory: Models, ITU-T X.501", December 2019,
              <https://www.itu.int/rec/T-REC-X.501/en>.

   [X.520]    "Information Technology - Open Systems Interconnection -
              The Directory: Selected attribute types", October 2019,
              <https://www.itu.int/rec/T-REC-X.520/en>.

   [X.690]    "ASN.1 encoding rules. Specification of Basic Encoding
              Rules (BER), Canonical Encoding Rules (CER) and
              Distinguished Encoding Rules (DER)", n.d.,
              <https://www.itu.int/rec/T-REC-X.690>.

9.2.  Informative References

   [CAB-Code] CA/Browser Forum, "CA/Browser Forum, "Baseline
              Requirements for the Issuance and Management of Publicly-
              Trusted Code Signing Certificates Version 3.8.0"", August
              2024, <https://cabforum.org/baseline-requirements-code-
              signing/>.

   [CAB-TLS]  CA/Browser Forum, "CA/Browser Forum, "Baseline
              Requirements for the Issuance and Management of Publicly-
              Trusted Certificates Version 2.1.4"", March 2025,
              <https://cabforum.org/baseline-requirements-documents/>.

   [CborMe]   Bormann, C., "CBOR Playground", May 2018,
              <https://cbor.me/>.






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   [GSMA-eUICC]
              GSMA, "GSMA eUICC PKI Certificate Policy Version 2.2",
              January 2025, <https://www.gsma.com/solutions-and-
              impact/technologies/esim/wp-content/uploads/2025/01/
              SGP.14-v2.2.pdf>.

   [GSMA-SGP.22]
              "GSMA RSP Technical Specification Version 3.1 Final",
              December 2023, <https://www.gsma.com/solutions-and-
              impact/technologies/esim/wp-content/uploads/2023/12/
              SGP.22-v3.1.pdf>.

   [IANA-AFI] "Address Family Numbers", n.d.,
              <https://www.iana.org/assignments/address-family-numbers/
              address-family-numbers.xhtml>.

   [IANA-CBOR-TAGS]
              IANA, "Concise Binary Object Representation (CBOR) Tags",
              n.d., <https://www.iana.org/assignments/cbor-tags/cbor-
              tags.xhtml>.

   [IANA-SAFI]
              "Subsequent Address Family Identifiers (SAFI) Parameters",
              n.d., <https://www.iana.org/assignments/safi-namespace/
              safi-namespace.xhtml>.

   [IEEE-802.1AR]
              Institute of Electrical and Electronics Engineers, "IEEE
              Standard for Local and metropolitan area networks–Secure
              Device Identity", IEEE Standard 802.1AR-2018 , August
              2018,
              <https://standards.ieee.org/standard/802_1AR-2018.html>.

   [RFC3161]  Adams, C., Cain, P., Pinkas, D., and R. Zuccherato,
              "Internet X.509 Public Key Infrastructure Time-Stamp
              Protocol (TSP)", RFC 3161, DOI 10.17487/RFC3161, August
              2001, <https://www.rfc-editor.org/rfc/rfc3161>.

   [RFC4524]  Zeilenga, K., Ed., "COSINE LDAP/X.500 Schema", RFC 4524,
              DOI 10.17487/RFC4524, June 2006,
              <https://www.rfc-editor.org/rfc/rfc4524>.

   [RFC6487]  Huston, G., Michaelson, G., and R. Loomans, "A Profile for
              X.509 PKIX Resource Certificates", RFC 6487,
              DOI 10.17487/RFC6487, February 2012,
              <https://www.rfc-editor.org/rfc/rfc6487>.





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   [RFC6955]  Schaad, J. and H. Prafullchandra, "Diffie-Hellman Proof-
              of-Possession Algorithms", RFC 6955, DOI 10.17487/RFC6955,
              May 2013, <https://www.rfc-editor.org/rfc/rfc6955>.

   [RFC6960]  Santesson, S., Myers, M., Ankney, R., Malpani, A.,
              Galperin, S., and C. Adams, "X.509 Internet Public Key
              Infrastructure Online Certificate Status Protocol - OCSP",
              RFC 6960, DOI 10.17487/RFC6960, June 2013,
              <https://www.rfc-editor.org/rfc/rfc6960>.

   [RFC7228]  Bormann, C., Ersue, M., and A. Keranen, "Terminology for
              Constrained-Node Networks", RFC 7228,
              DOI 10.17487/RFC7228, May 2014,
              <https://www.rfc-editor.org/rfc/rfc7228>.

   [RFC7468]  Josefsson, S. and S. Leonard, "Textual Encodings of PKIX,
              PKCS, and CMS Structures", RFC 7468, DOI 10.17487/RFC7468,
              April 2015, <https://www.rfc-editor.org/rfc/rfc7468>.

   [RFC7925]  Tschofenig, H., Ed. and T. Fossati, "Transport Layer
              Security (TLS) / Datagram Transport Layer Security (DTLS)
              Profiles for the Internet of Things", RFC 7925,
              DOI 10.17487/RFC7925, July 2016,
              <https://www.rfc-editor.org/rfc/rfc7925>.

   [RFC7932]  Alakuijala, J. and Z. Szabadka, "Brotli Compressed Data
              Format", RFC 7932, DOI 10.17487/RFC7932, July 2016,
              <https://www.rfc-editor.org/rfc/rfc7932>.

   [RFC8446]  Rescorla, E., "The Transport Layer Security (TLS) Protocol
              Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018,
              <https://www.rfc-editor.org/rfc/rfc8446>.

   [RFC8603]  Jenkins, M. and L. Zieglar, "Commercial National Security
              Algorithm (CNSA) Suite Certificate and Certificate
              Revocation List (CRL) Profile", RFC 8603,
              DOI 10.17487/RFC8603, May 2019,
              <https://www.rfc-editor.org/rfc/rfc8603>.

   [RFC8879]  Ghedini, A. and V. Vasiliev, "TLS Certificate
              Compression", RFC 8879, DOI 10.17487/RFC8879, December
              2020, <https://www.rfc-editor.org/rfc/rfc8879>.

   [RFC9000]  Iyengar, J., Ed. and M. Thomson, Ed., "QUIC: A UDP-Based
              Multiplexed and Secure Transport", RFC 9000,
              DOI 10.17487/RFC9000, May 2021,
              <https://www.rfc-editor.org/rfc/rfc9000>.




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   [RFC9147]  Rescorla, E., Tschofenig, H., and N. Modadugu, "The
              Datagram Transport Layer Security (DTLS) Protocol Version
              1.3", RFC 9147, DOI 10.17487/RFC9147, April 2022,
              <https://www.rfc-editor.org/rfc/rfc9147>.

   [RFC9148]  van der Stok, P., Kampanakis, P., Richardson, M., and S.
              Raza, "EST-coaps: Enrollment over Secure Transport with
              the Secure Constrained Application Protocol", RFC 9148,
              DOI 10.17487/RFC9148, April 2022,
              <https://www.rfc-editor.org/rfc/rfc9148>.

   [RFC9190]  Preuß Mattsson, J. and M. Sethi, "EAP-TLS 1.3: Using the
              Extensible Authentication Protocol with TLS 1.3",
              RFC 9190, DOI 10.17487/RFC9190, February 2022,
              <https://www.rfc-editor.org/rfc/rfc9190>.

   [RFC9191]  Sethi, M., Preuß Mattsson, J., and S. Turner, "Handling
              Large Certificates and Long Certificate Chains in TLS-
              Based EAP Methods", RFC 9191, DOI 10.17487/RFC9191,
              February 2022, <https://www.rfc-editor.org/rfc/rfc9191>.

   [RFC9528]  Selander, G., Preuß Mattsson, J., and F. Palombini,
              "Ephemeral Diffie-Hellman Over COSE (EDHOC)", RFC 9528,
              DOI 10.17487/RFC9528, March 2024,
              <https://www.rfc-editor.org/rfc/rfc9528>.

   [RFC9908]  Richardson, M., Ed., Friel, O., von Oheimb, D., and D.
              Harkins, "Clarification and Enhancement of the CSR
              Attributes Definition in RFC 7030", RFC 9908,
              DOI 10.17487/RFC9908, January 2026,
              <https://www.rfc-editor.org/rfc/rfc9908>.

   [SP-800-56A]
              Barker, E., Chen, L., Roginsky, A., Vassilev, A., and R.
              Davis, "Recommendation for Pair-Wise Key-Establishment
              Schemes Using Discrete Logarithm Cryptography",
              NIST Special Publication 800-56A Revision 3, April 2018,
              <https://doi.org/10.6028/NIST.SP.800-56Ar3>.

   [X.509-IoT]
              Forsby, F., Furuhed, M., Papadimitratos, P., and S. Raza,
              "Lightweight X.509 Digital Certificates for the Internet
              of Things.", Springer, Cham. Lecture Notes of the
              Institute for Computer Sciences, Social Informatics and
              Telecommunications Engineering, vol 242., July 2018,
              <https://doi.org/10.1007/978-3-319-93797-7_14>.





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Appendix A.  C509 Certificate Examples

A.1.  Example: RFC 7925 profiled X.509 Certificate

   Example of an [RFC7925] profiled X.509 certificate parsed with
   OpenSSL.

   Certificate:
       Data:
           Version: 3 (0x2)
           Serial Number: 128269 (0x1f50d)
           Signature Algorithm: ecdsa-with-SHA256
           Issuer: CN=RFC test CA
           Validity
               Not Before: Jan  1 00:00:00 2023 GMT
               Not After : Jan  1 00:00:00 2026 GMT
           Subject: CN=01-23-45-FF-FE-67-89-AB
           Subject Public Key Info:
               Public Key Algorithm: id-ecPublicKey
                   Public-Key: (256 bit)
                   pub:
                       04:b1:21:6a:b9:6e:5b:3b:33:40:f5:bd:f0:2e:69:
                       3f:16:21:3a:04:52:5e:d4:44:50:b1:01:9c:2d:fd:
                       38:38:ab:ac:4e:14:d8:6c:09:83:ed:5e:9e:ef:24:
                       48:c6:86:1c:c4:06:54:71:77:e6:02:60:30:d0:51:
                       f7:79:2a:c2:06
                   ASN1 OID: prime256v1
                   NIST CURVE: P-256
           X509v3 extensions:
               X509v3 Key Usage:
                   Digital Signature
       Signature Algorithm: ecdsa-with-SHA256
           30:46:02:21:00:d4:32:0b:1d:68:49:e3:09:21:9d:30:03:7e:
           13:81:66:f2:50:82:47:dd:da:e7:6c:ce:ea:55:05:3c:10:8e:
           90:02:21:00:d5:51:f6:d6:01:06:f1:ab:b4:84:cf:be:62:56:
           c1:78:e4:ac:33:14:ea:19:19:1e:8b:60:7d:a5:ae:3b:da:16

   The DER encoding of the above certificate is 316 bytes.













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   30 82 01 38 30 81 de a0 03 02 01 02 02 03 01 f5 0d 30 0a 06 08 2a 86
   48 ce 3d 04 03 02 30 16 31 14 30 12 06 03 55 04 03 0c 0b 52 46 43 20
   74 65 73 74 20 43 41 30 1e 17 0d 32 33 30 31 30 31 30 30 30 30 30 30
   5a 17 0d 32 36 30 31 30 31 30 30 30 30 30 30 5a 30 22 31 20 30 1e 06
   03 55 04 03 0c 17 30 31 2d 32 33 2d 34 35 2d 46 46 2d 46 45 2d 36 37
   2d 38 39 2d 41 42 30 59 30 13 06 07 2a 86 48 ce 3d 02 01 06 08 2a 86
   48 ce 3d 03 01 07 03 42 00 04 b1 21 6a b9 6e 5b 3b 33 40 f5 bd f0 2e
   69 3f 16 21 3a 04 52 5e d4 44 50 b1 01 9c 2d fd 38 38 ab ac 4e 14 d8
   6c 09 83 ed 5e 9e ef 24 48 c6 86 1c c4 06 54 71 77 e6 02 60 30 d0 51
   f7 79 2a c2 06 a3 0f 30 0d 30 0b 06 03 55 1d 0f 04 04 03 02 07 80 30
   0a 06 08 2a 86 48 ce 3d 04 03 02 03 49 00 30 46 02 21 00 d4 32 0b 1d
   68 49 e3 09 21 9d 30 03 7e 13 81 66 f2 50 82 47 dd da e7 6c ce ea 55
   05 3c 10 8e 90 02 21 00 d5 51 f6 d6 01 06 f1 ab b4 84 cf be 62 56 c1
   78 e4 ac 33 14 ea 19 19 1e 8b 60 7d a5 ae 3b da 16

A.1.1.  Example: C509 Certificate Encoding

   This section shows the C509 encoding of the X.509 certificate in the
   previous section.  The point-compressed public key is represented as
   described in Section 3.2.1.

   Figure 21 shows the diagnostic notation of the unwrapped CBOR
   sequence, ~C509Certificate, see Section 3.1.

   /This defines a CBOR Sequence (RFC 8742):/

     3,                   / version and certificate type /
     h'01f50d',           / certificateSerialNumber /
     0,                   / signatureAlgorithm /
     "RFC test CA",       / issuer /
     1672531200,          / notBefore /
     1767225600,          / notAfter /
     48(h'0123456789AB'), / subject, EUI-64 /
     1,                   / subjectPublicKeyAlgorithm /
     h'FEB1216AB96E5B3B3340F5BDF02E693F16213A04525ED44450
       B1019C2DFD3838AB',
     1,                   / single extension:
                            non-critical keyUsage
                            digitalSignature /
     h'D4320B1D6849E309219D30037E138166F2508247DDDAE76CCE
       EA55053C108E90D551F6D60106F1ABB484CFBE6256C178E4AC
       3314EA19191E8B607DA5AE3BDA16'

          Figure 21: CBOR diagnostic notation of ~C509Certificate

   Figure 22 shows the plain hex format of the unwrapped CBOR sequence.
   The size is 140 bytes.




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   03
   43 01 F5 0D
   00
   6B 52 46 43 20 74 65 73 74 20 43 41
   1A 63 B0 CD 00
   1A 69 55 B9 00
   D8 30 46 01 23 45 67 89 AB
   01
   58 21 FE B1 21 6A B9 6E 5B 3B 33 40 F5 BD F0 2E 69 3F 16 21 3A 04 52
   5E D4 44 50 B1 01 9C 2D FD 38 38 AB
   01
   58 40 D4 32 0B 1D 68 49 E3 09 21 9D 30 03 7E 13 81 66 F2 50 82 47 DD
   DA E7 6C CE EA 55 05 3C 10 8E 90 D5 51 F6 D6 01 06 F1 AB B4 84 CF BE
   62 56 C1 78 E4 AC 33 14 EA 19 19 1E 8B 60 7D A5 AE 3B DA 16

           Figure 22: CBOR plain hex format of ~C509Certificate.

A.1.2.  Example: Natively Signed C509 Certificate

   This section shows the natively signed C509 certificate corresponding
   to the certificate in the previous section.  It is identical except
   for c509CertificateType, the encoding of point compression (see
   Section 3.2.1), and signatureValue.

   Figure 23 shows the diagnostic notation of the natively signed
   unwrapped CBOR sequence, ~C509Certificate.

   /This defines a CBOR Sequence (RFC 8742):/

     2,
     h'01f50d',
     0,
     "RFC test CA",
     1672531200,
     1767225600,
     48(h'0123456789AB'),
     1,
     h'02B1216AB96E5B3B3340F5BDF02E693F16213A04525ED44450
       B1019C2DFD3838AB',
     1,
     h'EB0D472731F689BC00F5880B12C68B3F9FD38B23FADFCA2095
       0F3F241B60A202579CAC28CD3B7494D5FA5D8BBAB4600357E5
       50AB9FA9A65D9BA2B3B82E668CC6'

          Figure 23: CBOR diagnostic notation of ~C509Certificate

   Figure 24 shows the plain hex format of the natively signed unwrapped
   CBOR sequence.  The size is 140 bytes.



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   02
   43 01 F5 0D
   00
   6B 52 46 43 20 74 65 73 74 20 43 41
   1A 63 B0 CD 00
   1A 69 55 B9 00
   D8 30 46 01 23 45 67 89 AB
   01
   58 21 02 B1 21 6A B9 6E 5B 3B 33 40 F5 BD F0 2E 69 3F 16 21 3A 04 52
   5E D4 44 50 B1 01 9C 2D FD 38 38 AB
   01
   58 40 EB 0D 47 27 31 F6 89 BC 00 F5 88 0B 12 C6 8B 3F 9F D3 8B 23 FA
   DF CA 20 95 0F 3F 24 1B 60 A2 02 57 9C AC 28 CD 3B 74 94 D5 FA 5D 8B
   BA B4 60 03 57 E5 50 AB 9F A9 A6 5D 9B A2 B3 B8 2E 66 8C C6

           Figure 24: CBOR plain hex format of ~C509Certificate.

A.1.3.  C509 for Diffie-Hellman keys

   The two previous examples illustrate keyUsage digitalSignature.  A
   C509 certificate for a public Diffie-Hellman key would instead have
   key usage keyAgreement encoded according to Section 3.3 (in this case
   of single extension encoded as integer 16 instead of 1 for digital
   signature) but otherwise identical in format.  Note that
   Section 5.6.3.2 of [SP-800-56A] allows a key agreement key pair to be
   used to sign a certification request.

A.1.4.  Example: Additional Keys for the Example Certificates

   Below are the issuer key pair and the subject private key
   corresponding to the above example certificates.  The private keys
   are encoded as in COSE [RFC9052].  This issuer key pair can be used
   to sign or verify the example certificates, and the subject private
   key allows those certificates to be used in test vectors for other
   protocols such as EDHOC.

   issuerPublicKeyAlgorithm :
   1 (EC Public Key (Weierstrass) with secp256r1)

   issuerPublicKey :
   h'02AE4CDB01F614DEFC7121285FDC7F5C6D1D42C95647F061BA0080DF678867845E'

   issuerPrivateKey :
   h'DC66B3415456D649429B53223DF7532B942D6B0E0842C30BCA4C0ACF91547BB2'

   subjectPrivateKey :
   h'D718111F3F9BD91B92FF6877F386BDBFCEA7154268FD7F2FB56EE17D99EA16D4'




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A.1.5.  Examples: C509Certificate and C509CertData

   This section exemplifies other CBOR objects defined in this
   specification, based on the natively signed C509 certificate in
   Appendix A.1.2.

   Figure 25 shows the encoding of the corresponding C509Certificate,
   i.e., the CBOR array wrapping of the CBOR sequence ~C509Certificate,
   see Section 3.1.

   8B
   02
   43 01 F5 0D
   00
   6B 52 46 43 20 74 65 73 74 20 43 41
   1A 63 B0 CD 00
   1A 69 55 B9 00
   D8 30 46 01 23 45 67 89 AB
   01
   58 21 02 B1 21 6A B9 6E 5B 3B 33 40 F5 BD F0 2E 69 3F 16 21 3A 04 52
   5E D4 44 50 B1 01 9C 2D FD 38 38 AB
   01
   58 40 EB 0D 47 27 31 F6 89 BC 00 F5 88 0B 12 C6 8B 3F 9F D3 8B 23 FA
   DF CA 20 95 0F 3F 24 1B 60 A2 02 57 9C AC 28 CD 3B 74 94 D5 FA 5D 8B
   BA B4 60 03 57 E5 50 AB 9F A9 A6 5D 9B A2 B3 B8 2E 66 8C C6

           Figure 25: C509Certificate: The CBOR array wrapping of
                              ~C509Certificate

   Note that C509Certificate is identical to ~C509Certificate in
   Appendix A.1.2 except for the prefix 8B (which indicates that it is a
   CBOR array with 11 elements).

   Figure 26 shows the encoding of the corresponding C509CertData, i.e.,
   the CBOR byte string wrapping of the CBOR sequence ~C509Certificate,
   see Section 3.4.















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   58 8C
   02
   43 01 F5 0D
   00
   6B 52 46 43 20 74 65 73 74 20 43 41
   1A 63 B0 CD 00
   1A 69 55 B9 00
   D8 30 46 01 23 45 67 89 AB
   01
   58 21 02 B1 21 6A B9 6E 5B 3B 33 40 F5 BD F0 2E 69 3F 16 21 3A 04 52
   5E D4 44 50 B1 01 9C 2D FD 38 38 AB
   01
   58 40 EB 0D 47 27 31 F6 89 BC 00 F5 88 0B 12 C6 8B 3F 9F D3 8B 23 FA
   DF CA 20 95 0F 3F 24 1B 60 A2 02 57 9C AC 28 CD 3B 74 94 D5 FA 5D 8B
   BA B4 60 03 57 E5 50 AB 9F A9 A6 5D 9B A2 B3 B8 2E 66 8C C6

           Figure 26: C509CertData: CBOR byte string wrapping of
                             ~C509Certificate.

   Note that C509CertData is identical to ~C509Certificate in
   Appendix A.1.2 except for the prefix 58 8C (which indicates that it
   is a CBOR byte string of 140 bytes).

A.2.  Example: IEEE 802.1AR profiled X.509 Certificate

   An example of an IEEE 802.1AR profiled X.509 certificate (Secure
   Device Identifier, DevID) is provided in Appendix C.2 of [RFC9148].
   The certificate is shown below including details of the
   hardwareModuleName type of otherName in subjectAltName, see
   Section 3.3.





















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   Certificate:
     Data:
       Version: 3 (0x2)
       Serial Number: 9112578475118446130 (0x7e7661d7b54e4632)
       Signature Algorithm: ecdsa-with-SHA256
       Issuer: C=US, ST=CA, O=Example Inc, OU=certification,
               CN=802.1AR CA
       Validity
         Not Before: Jan 31 11:29:16 2019 GMT
         Not After : Dec 31 23:59:59 9999 GMT
       Subject: C=US, ST=CA, L=LA, O=example Inc,
                OU=IoT/serialNumber=Wt1234
       Subject Public Key Info:
         Public Key Algorithm: id-ecPublicKey
           Public-Key: (256 bit)
           pub:
             04:c8:b4:21:f1:1c:25:e4:7e:3a:c5:71:23:bf:2d:
             9f:dc:49:4f:02:8b:c3:51:cc:80:c0:3f:15:0b:f5:
             0c:ff:95:8d:75:41:9d:81:a6:a2:45:df:fa:e7:90:
             be:95:cf:75:f6:02:f9:15:26:18:f8:16:a2:b2:3b:
             56:38:e5:9f:d9
             ASN1 OID: prime256v1
             NIST CURVE: P-256
       X509v3 extensions:
         X509v3 Basic Constraints:
           CA:FALSE
         X509v3 Subject Key Identifier:
           96:60:0D:87:16:BF:7F:D0:E7:52:D0:AC:76:07:77:AD:66:5D:02:A0
         X509v3 Authority Key Identifier:
           68:D1:65:51:F9:51:BF:C8:2A:43:1D:0D:9F:08:BC:2D:20:5B:11:60
         X509v3 Key Usage: critical
           Digital Signature, Key Encipherment
         X509v3 Subject Alternative Name:
           otherName:
             type-id: 1.3.6.1.5.5.7.8.4 (id-on-hardwareModuleName)
             value:
               hwType: 1.3.6.1.4.1.6715.10.1
               hwSerialNum: 01:02:03:04
     Signature Algorithm: ecdsa-with-SHA256
     Signature Value:
       30:46:02:21:00:c0:d8:19:96:d2:50:7d:69:3f:3c:48:ea:a5:
       ee:94:91:bd:a6:db:21:40:99:d9:81:17:c6:3b:36:13:74:cd:
       86:02:21:00:a7:74:98:9f:4c:32:1a:5c:f2:5d:83:2a:4d:33:
       6a:08:ad:67:df:20:f1:50:64:21:18:8a:0a:de:6d:34:92:36

   The DER encoding of the certificate is 577 bytes:





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   30 82 02 3D 30 82 01 E2 A0 03 02 01 02 02 08 7E 76 61 D7 B5 4E 46 32
   30 0A 06 08 2A 86 48 CE 3D 04 03 02 30 5D 31 0B 30 09 06 03 55 04 06
   13 02 55 53 31 0B 30 09 06 03 55 04 08 0C 02 43 41 31 14 30 12 06 03
   55 04 0A 0C 0B 45 78 61 6D 70 6C 65 20 49 6E 63 31 16 30 14 06 03 55
   04 0B 0C 0D 63 65 72 74 69 66 69 63 61 74 69 6F 6E 31 13 30 11 06 03
   55 04 03 0C 0A 38 30 32 2E 31 41 52 20 43 41 30 20 17 0D 31 39 30 31
   33 31 31 31 32 39 31 36 5A 18 0F 39 39 39 39 31 32 33 31 32 33 35 39
   35 39 5A 30 5C 31 0B 30 09 06 03 55 04 06 13 02 55 53 31 0B 30 09 06
   03 55 04 08 0C 02 43 41 31 0B 30 09 06 03 55 04 07 0C 02 4C 41 31 14
   30 12 06 03 55 04 0A 0C 0B 65 78 61 6D 70 6C 65 20 49 6E 63 31 0C 30
   0A 06 03 55 04 0B 0C 03 49 6F 54 31 0F 30 0D 06 03 55 04 05 13 06 57
   74 31 32 33 34 30 59 30 13 06 07 2A 86 48 CE 3D 02 01 06 08 2A 86 48
   CE 3D 03 01 07 03 42 00 04 C8 B4 21 F1 1C 25 E4 7E 3A C5 71 23 BF 2D
   9F DC 49 4F 02 8B C3 51 CC 80 C0 3F 15 0B F5 0C FF 95 8D 75 41 9D 81
   A6 A2 45 DF FA E7 90 BE 95 CF 75 F6 02 F9 15 26 18 F8 16 A2 B2 3B 56
   38 E5 9F D9 A3 81 8A 30 81 87 30 09 06 03 55 1D 13 04 02 30 00 30 1D
   06 03 55 1D 0E 04 16 04 14 96 60 0D 87 16 BF 7F D0 E7 52 D0 AC 76 07
   77 AD 66 5D 02 A0 30 1F 06 03 55 1D 23 04 18 30 16 80 14 68 D1 65 51
   F9 51 BF C8 2A 43 1D 0D 9F 08 BC 2D 20 5B 11 60 30 0E 06 03 55 1D 0F
   01 01 FF 04 04 03 02 05 A0 30 2A 06 03 55 1D 11 04 23 30 21 A0 1F 06
   08 2B 06 01 05 05 07 08 04 A0 13 30 11 06 09 2B 06 01 04 01 B4 3B 0A
   01 04 04 01 02 03 04 30 0A 06 08 2A 86 48 CE 3D 04 03 02 03 49 00 30
   46 02 21 00 C0 D8 19 96 D2 50 7D 69 3F 3C 48 EA A5 EE 94 91 BD A6 DB
   21 40 99 D9 81 17 C6 3B 36 13 74 CD 86 02 21 00 A7 74 98 9F 4C 32 1A
   5C F2 5D 83 2A 4D 33 6A 08 AD 67 DF 20 F1 50 64 21 18 8A 0A DE 6D 34
   92 36

A.2.1.  Example: C509 Certificate Encoding

   The CBOR encoding (~C509Certificate) of the same X.509 certificate is
   shown below in CBOR diagnostic format.




















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   /This defines a CBOR Sequence (RFC 8742):/

    3,
    h'7E7661D7B54E4632',
    0,
    [
     -4, "US",
      6, "CA",
      8, "Example Inc",
      9, "certification",
      1, "802.1AR CA"
    ],
    1548934156,
    null,
    [
     -4, "US",
      6, "CA",
      5, "LA",
      8, "example Inc",
      9, "IoT",
     -3, "Wt1234"
    ],
    1,
    h'FDC8B421F11C25E47E3AC57123BF2D9FDC494F028BC351CC80C03F150BF50CFF
      95',
    [
      4, -2,
      1, h'96600D8716BF7FD0E752D0AC760777AD665D02A0',
      7, h'68D16551F951BFC82A431D0D9F08BC2D205B1160',
     -2, 5,
     3, [-1, [h'2B06010401B43B0A01', h'01020304']]
        / subjectAltName with hardwareModuleName /
    ],
    h'C0D81996D2507D693F3C48EAA5EE9491BDA6DB214099D98117C63B361374CD86
      A774989F4C321A5CF25D832A4D336A08AD67DF20F1506421188A0ADE6D349236'

   The size of the CBOR encoding (CBOR sequence) is 275 bytes:














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   03 48 7E 76 61 D7 B5 4E 46 32 00 8A 23 62 55 53 06 62 43 41 08 6B 45
   78 61 6D 70 6C 65 20 49 6E 63 09 6D 63 65 72 74 69 66 69 63 61 74 69
   6F 6E 01 6A 38 30 32 2E 31 41 52 20 43 41 1A 5C 52 DC 0C F6 8C 23 62
   55 53 06 62 43 41 05 62 4C 41 08 6B 65 78 61 6D 70 6C 65 20 49 6E 63
   09 63 49 6F 54 22 66 57 74 31 32 33 34 01 58 21 FD C8 B4 21 F1 1C 25
   E4 7E 3A C5 71 23 BF 2D 9F DC 49 4F 02 8B C3 51 CC 80 C0 3F 15 0B F5
   0C FF 95 8A 04 21 01 54 96 60 0D 87 16 BF 7F D0 E7 52 D0 AC 76 07 77
   AD 66 5D 02 A0 07 54 68 D1 65 51 F9 51 BF C8 2A 43 1D 0D 9F 08 BC 2D
   20 5B 11 60 21 05 03 82 20 82 49 2B 06 01 04 01 B4 3B 0A 01 44 01 02
   03 04 58 40 C0 D8 19 96 D2 50 7D 69 3F 3C 48 EA A5 EE 94 91 BD A6 DB
   21 40 99 D9 81 17 C6 3B 36 13 74 CD 86 A7 74 98 9F 4C 32 1A 5C F2 5D
   83 2A 4D 33 6A 08 AD 67 DF 20 F1 50 64 21 18 8A 0A DE 6D 34 92 36

A.3.  Example: CAB Baseline ECDSA HTTPS X.509 Certificate

   The www.ietf.org HTTPS server replies with a certificate message with
   2 certificates.  The DER encoding of the first certificate is 1209
   bytes.

   30 82 04 b5 30 82 04 5a a0 03 02 01 02 02 10 04 7f a1 e3 19 28 ee 40
   3b a0 b8 3a 39 56 73 fc 30 0a 06 08 2a 86 48 ce 3d 04 03 02 30 4a 31
   0b 30 09 06 03 55 04 06 13 02 55 53 31 19 30 17 06 03 55 04 0a 13 10
   43 6c 6f 75 64 66 6c 61 72 65 2c 20 49 6e 63 2e 31 20 30 1e 06 03 55
   04 03 13 17 43 6c 6f 75 64 66 6c 61 72 65 20 49 6e 63 20 45 43 43 20
   43 41 2d 33 30 1e 17 0d 32 30 30 37 32 39 30 30 30 30 30 30 5a 17 0d
   32 31 30 37 32 39 31 32 30 30 30 30 5a 30 6d 31 0b 30 09 06 03 55 04
   06 13 02 55 53 31 0b 30 09 06 03 55 04 08 13 02 43 41 31 16 30 14 06
   03 55 04 07 13 0d 53 61 6e 20 46 72 61 6e 63 69 73 63 6f 31 19 30 17
   06 03 55 04 0a 13 10 43 6c 6f 75 64 66 6c 61 72 65 2c 20 49 6e 63 2e
   31 1e 30 1c 06 03 55 04 03 13 15 73 6e 69 2e 63 6c 6f 75 64 66 6c 61
   72 65 73 73 6c 2e 63 6f 6d 30 59 30 13 06 07 2a 86 48 ce 3d 02 01 06
   08 2a 86 48 ce 3d 03 01 07 03 42 00 04 96 3e cd d8 4d cd 1b 93 a1 cf
   43 2d 1a 72 17 d6 c6 3b de 33 55 a0 2f 8c fb 5a d8 99 4c d4 4e 20 5f
   15 f6 e3 d2 3b 38 2b a6 49 9b b1 7f 34 1f a5 92 fa 21 86 1f 16 d3 12
   06 63 24 05 fd 70 42 bd a3 82 02 fd 30 82 02 f9 30 1f 06 03 55 1d 23
   04 18 30 16 80 14 a5 ce 37 ea eb b0 75 0e 94 67 88 b4 45 fa d9 24 10
   87 96 1f 30 1d 06 03 55 1d 0e 04 16 04 14 cc 0b 50 e7 d8 37 db f2 43
   f3 85 3d 48 60 f5 3b 39 be 9b 2a 30 2e 06 03 55 1d 11 04 27 30 25 82
   15 73 6e 69 2e 63 6c 6f 75 64 66 6c 61 72 65 73 73 6c 2e 63 6f 6d 82
   0c 77 77 77 2e 69 65 74 66 2e 6f 72 67 30 0e 06 03 55 1d 0f 01 01 ff
   04 04 03 02 07 80 30 1d 06 03 55 1d 25 04 16 30 14 06 08 2b 06 01 05
   05 07 03 01 06 08 2b 06 01 05 05 07 03 02 30 7b 06 03 55 1d 1f 04 74
   30 72 30 37 a0 35 a0 33 86 31 68 74 74 70 3a 2f 2f 63 72 6c 33 2e 64
   69 67 69 63 65 72 74 2e 63 6f 6d 2f 43 6c 6f 75 64 66 6c 61 72 65 49
   6e 63 45 43 43 43 41 2d 33 2e 63 72 6c 30 37 a0 35 a0 33 86 31 68 74
   74 70 3a 2f 2f 63 72 6c 34 2e 64 69 67 69 63 65 72 74 2e 63 6f 6d 2f
   43 6c 6f 75 64 66 6c 61 72 65 49 6e 63 45 43 43 43 41 2d 33 2e 63 72
   6c 30 4c 06 03 55 1d 20 04 45 30 43 30 37 06 09 60 86 48 01 86 fd 6c



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   01 01 30 2a 30 28 06 08 2b 06 01 05 05 07 02 01 16 1c 68 74 74 70 73
   3a 2f 2f 77 77 77 2e 64 69 67 69 63 65 72 74 2e 63 6f 6d 2f 43 50 53
   30 08 06 06 67 81 0c 01 02 02 30 76 06 08 2b 06 01 05 05 07 01 01 04
   6a 30 68 30 24 06 08 2b 06 01 05 05 07 30 01 86 18 68 74 74 70 3a 2f
   2f 6f 63 73 70 2e 64 69 67 69 63 65 72 74 2e 63 6f 6d 30 40 06 08 2b
   06 01 05 05 07 30 02 86 34 68 74 74 70 3a 2f 2f 63 61 63 65 72 74 73
   2e 64 69 67 69 63 65 72 74 2e 63 6f 6d 2f 43 6c 6f 75 64 66 6c 61 72
   65 49 6e 63 45 43 43 43 41 2d 33 2e 63 72 74 30 0c 06 03 55 1d 13 01
   01 ff 04 02 30 00 30 82 01 05 06 0a 2b 06 01 04 01 d6 79 02 04 02 04
   81 f6 04 81 f3 00 f1 00 76 00 f6 5c 94 2f d1 77 30 22 14 54 18 08 30
   94 56 8e e3 4d 13 19 33 bf df 0c 2f 20 0b cc 4e f1 64 e3 00 00 01 73
   9c 83 5f 8e 00 00 04 03 00 47 30 45 02 21 00 f8 d1 b4 a9 3d 2f 0d 4c
   41 76 df b4 88 bc c7 3b 86 44 3d 7d e0 0e 6a c8 17 4d 89 48 a8 84 36
   68 02 20 29 ff 5a 34 06 8a 24 0c 69 50 27 88 e8 ee 25 ab 7e d2 cb cf
   68 6e ce 7b 5f 96 b4 31 a9 07 02 fa 00 77 00 5c dc 43 92 fe e6 ab 45
   44 b1 5e 9a d4 56 e6 10 37 fb d5 fa 47 dc a1 73 94 b2 5e e6 f6 c7 0e
   ca 00 00 01 73 9c 83 5f be 00 00 04 03 00 48 30 46 02 21 00 e8 91 c1
   97 bf b0 e3 d3 0c b6 ce e6 0d 94 c3 c7 5f d1 17 53 36 93 11 08 d8 98
   12 d4 d2 9d 81 d0 02 21 00 a1 59 d1 6c 46 47 d1 48 37 57 fc d6 ce 4e
   75 ec 7b 5e f6 57 ef e0 28 f8 e5 cc 47 92 68 2d ac 43 30 0a 06 08 2a
   86 48 ce 3d 04 03 02 03 49 00 30 46 02 21 00 bd 63 cf 4f 7e 5c fe 6c
   29 38 5e a7 1c fb fc 1e 3f 7b 1c d0 72 51 a2 21 f7 77 69 c0 f4 71 df
   ea 02 21 00 b5 c0 6c c4 58 54 fa 30 b2 82 88 b1 d3 bb 9a 66 61 ed 50
   31 72 5b 1a 82 02 e0 da 5b 59 f9 54 02

A.3.1.  Example: C509 Certificate Encoding

   The CBOR encoding (~C509Certificate) of the first X.509 certificate
   is shown below in CBOR diagnostic format.

   /This defines a CBOR Sequence (RFC 8742):/

   3,
   h'047FA1E31928EE403BA0B83A395673FC',
   0,
   [
    -4, "US",
    -8, "Cloudflare, Inc.",
    -1, "Cloudflare Inc ECC CA-3"
   ],
   1595980800,
   1627560000,
   [
    -4, "US",
    -6, "CA",
    -5, "San Francisco",
    -8, "Cloudflare, Inc.",
    -1, "sni.cloudflaressl.com"



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   ],
   1,
   h'FD963ECDD84DCD1B93A1CF432D1A7217D6C63BDE3355A02F8CFB5AD8994CD44E
     20',
   [
    7, h'A5CE37EAEBB0750E946788B445FAD9241087961F',
    1, h'CC0B50E7D837DBF243F3853D4860F53B39BE9B2A',
    3, [2, "sni.cloudflaressl.com", 2, "www.ietf.org"],
   -2, 1,
    8, [1, 2],
    5, [
        ["http://crl3.digicert.com/CloudflareIncECCCA-3.crl",
          null, null],
        ["http://crl4.digicert.com/CloudflareIncECCCA-3.crl",
          null, null]
       ],
    6, [h'6086480186FD6C0101', [1, "https://www.digicert.com/CPS"],
        2, []],
    9, [1, "http://ocsp.digicert.com",
        2, "http://cacerts.digicert.com/CloudflareIncECCCA-3.crt"],
   -4, -2,
    h'2B06010401D679020402',
    h'0481F300F1007600F65C942FD1773022145418083094568EE34D131933BFDF0C
      2F200BCC4EF164E3000001739C835F8E0000040300473045022100F8D1B4A93D
      2F0D4C4176DFB488BCC73B86443D7DE00E6AC8174D8948A8843668022029FF5A
      34068A240C69502788E8EE25AB7ED2CBCF686ECE7B5F96B431A90702FA007700
      5CDC4392FEE6AB4544B15E9AD456E61037FBD5FA47DCA17394B25EE6F6C70ECA
      000001739C835FBE0000040300483046022100E891C197BFB0E3D30CB6CEE60D
      94C3C75FD1175336931108D89812D4D29D81D0022100A159D16C4647D1483757
      FCD6CE4E75EC7B5EF657EFE028F8E5CC4792682DAC43'
   ],
   h'BD63CF4F7E5CFE6C29385EA71CFBFC1E3F7B1CD07251A221F77769C0F471DFEA
     B5C06CC45854FA30B28288B1D3BB9A6661ED5031725B1A8202E0DA5B59F95402'

   The size of the CBOR encoding (CBOR sequence) is 835 bytes.

A.4.  Example: CAB Baseline RSA HTTPS X.509 Certificate

   The tools.ietf.org HTTPS server replies with a certificate message
   with 4 certificates.  The DER encoding of the first certificate is
   1647 bytes.

   30 82 06 6b 30 82 05 53 a0 03 02 01 02 02 09 00 a6 a5 5c 87 0e 39 b4
   0e 30 0d 06 09 2a 86 48 86 f7 0d 01 01 0b 05 00 30 81 c6 31 0b 30 09
   06 03 55 04 06 13 02 55 53 31 10 30 0e 06 03 55 04 08 13 07 41 72 69
   7a 6f 6e 61 31 13 30 11 06 03 55 04 07 13 0a 53 63 6f 74 74 73 64 61
   6c 65 31 25 30 23 06 03 55 04 0a 13 1c 53 74 61 72 66 69 65 6c 64 20
   54 65 63 68 6e 6f 6c 6f 67 69 65 73 2c 20 49 6e 63 2e 31 33 30 31 06



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   03 55 04 0b 13 2a 68 74 74 70 3a 2f 2f 63 65 72 74 73 2e 73 74 61 72
   66 69 65 6c 64 74 65 63 68 2e 63 6f 6d 2f 72 65 70 6f 73 69 74 6f 72
   79 2f 31 34 30 32 06 03 55 04 03 13 2b 53 74 61 72 66 69 65 6c 64 20
   53 65 63 75 72 65 20 43 65 72 74 69 66 69 63 61 74 65 20 41 75 74 68
   6f 72 69 74 79 20 2d 20 47 32 30 1e 17 0d 32 30 31 30 30 31 31 39 33
   38 33 36 5a 17 0d 32 31 31 31 30 32 31 39 33 38 33 36 5a 30 3e 31 21
   30 1f 06 03 55 04 0b 13 18 44 6f 6d 61 69 6e 20 43 6f 6e 74 72 6f 6c
   20 56 61 6c 69 64 61 74 65 64 31 19 30 17 06 03 55 04 03 0c 10 2a 2e
   74 6f 6f 6c 73 2e 69 65 74 66 2e 6f 72 67 30 82 01 22 30 0d 06 09 2a
   86 48 86 f7 0d 01 01 01 05 00 03 82 01 0f 00 30 82 01 0a 02 82 01 01
   00 b1 e1 37 e8 eb 82 d6 89 fa db f5 c2 4b 77 f0 2c 4a de 72 6e 3e 13
   60 d1 a8 66 1e c4 ad 3d 32 60 e5 f0 99 b5 f4 7a 7a 48 55 21 ee 0e 39
   12 f9 ce 0d ca f5 69 61 c7 04 ed 6e 0f 1d 3b 1e 50 88 79 3a 0e 31 41
   16 f1 b1 02 64 68 a5 cd f5 4a 0a ca 99 96 35 08 c3 7e 27 5d d0 a9 cf
   f3 e7 28 af 37 d8 b6 7b dd f3 7e ae 6e 97 7f f7 ca 69 4e cc d0 06 df
   5d 27 9b 3b 12 e7 e6 fe 08 6b 52 7b 82 11 7c 72 b3 46 eb c1 e8 78 b8
   0f cb e1 eb bd 06 44 58 dc 83 50 b2 a0 62 5b dc 81 b8 36 e3 9e 7c 79
   b2 a9 53 8a e0 0b c9 4a 2a 13 39 31 13 bd 2c cf a8 70 cf 8c 8d 3d 01
   a3 88 ae 12 00 36 1d 1e 24 2b dd 79 d8 53 01 26 ed 28 4f c9 86 94 83
   4e c8 e1 14 2e 85 b3 af d4 6e dd 69 46 af 41 25 0e 7a ad 8b f2 92 ca
   79 d9 7b 32 4f f7 77 e8 f9 b4 4f 23 5c d4 5c 03 ae d8 ab 3a ca 13 5f
   5d 5d 5d a1 02 03 01 00 01 a3 82 02 e1 30 82 02 dd 30 0c 06 03 55 1d
   13 01 01 ff 04 02 30 00 30 1d 06 03 55 1d 25 04 16 30 14 06 08 2b 06
   01 05 05 07 03 01 06 08 2b 06 01 05 05 07 03 02 30 0e 06 03 55 1d 0f
   01 01 ff 04 04 03 02 05 a0 30 3d 06 03 55 1d 1f 04 36 30 34 30 32 a0
   30 a0 2e 86 2c 68 74 74 70 3a 2f 2f 63 72 6c 2e 73 74 61 72 66 69 65
   6c 64 74 65 63 68 2e 63 6f 6d 2f 73 66 69 67 32 73 31 2d 32 34 32 2e
   63 72 6c 30 63 06 03 55 1d 20 04 5c 30 5a 30 4e 06 0b 60 86 48 01 86
   fd 6e 01 07 17 01 30 3f 30 3d 06 08 2b 06 01 05 05 07 02 01 16 31 68
   74 74 70 3a 2f 2f 63 65 72 74 69 66 69 63 61 74 65 73 2e 73 74 61 72
   66 69 65 6c 64 74 65 63 68 2e 63 6f 6d 2f 72 65 70 6f 73 69 74 6f 72
   79 2f 30 08 06 06 67 81 0c 01 02 01 30 81 82 06 08 2b 06 01 05 05 07
   01 01 04 76 30 74 30 2a 06 08 2b 06 01 05 05 07 30 01 86 1e 68 74 74
   70 3a 2f 2f 6f 63 73 70 2e 73 74 61 72 66 69 65 6c 64 74 65 63 68 2e
   63 6f 6d 2f 30 46 06 08 2b 06 01 05 05 07 30 02 86 3a 68 74 74 70 3a
   2f 2f 63 65 72 74 69 66 69 63 61 74 65 73 2e 73 74 61 72 66 69 65 6c
   64 74 65 63 68 2e 63 6f 6d 2f 72 65 70 6f 73 69 74 6f 72 79 2f 73 66
   69 67 32 2e 63 72 74 30 1f 06 03 55 1d 23 04 18 30 16 80 14 25 45 81
   68 50 26 38 3d 3b 2d 2c be cd 6a d9 b6 3d b3 66 63 30 2b 06 03 55 1d
   11 04 24 30 22 82 10 2a 2e 74 6f 6f 6c 73 2e 69 65 74 66 2e 6f 72 67
   82 0e 74 6f 6f 6c 73 2e 69 65 74 66 2e 6f 72 67 30 1d 06 03 55 1d 0e
   04 16 04 14 ad 8a b4 1c 07 51 d7 92 89 07 b0 b7 84 62 2f 36 55 7a 5f
   4d 30 82 01 06 06 0a 2b 06 01 04 01 d6 79 02 04 02 04 81 f7 04 81 f4
   00 f2 00 77 00 f6 5c 94 2f d1 77 30 22 14 54 18 08 30 94 56 8e e3 4d
   13 19 33 bf df 0c 2f 20 0b cc 4e f1 64 e3 00 00 01 74 e5 ac 71 13 00
   00 04 03 00 48 30 46 02 21 00 8c f5 48 52 ce 56 35 43 39 11 cf 10 cd
   b9 1f 52 b3 36 39 22 3a d1 38 a4 1d ec a6 fe de 1f e9 0f 02 21 00 bc
   a2 25 43 66 c1 9a 26 91 c4 7a 00 b5 b6 53 ab bd 44 c2 f8 ba ae f4 d2



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   da f2 52 7c e6 45 49 95 00 77 00 5c dc 43 92 fe e6 ab 45 44 b1 5e 9a
   d4 56 e6 10 37 fb d5 fa 47 dc a1 73 94 b2 5e e6 f6 c7 0e ca 00 00 01
   74 e5 ac 72 3c 00 00 04 03 00 48 30 46 02 21 00 a5 e0 90 6e 63 e9 1d
   4f dd ef ff 03 52 b9 1e 50 89 60 07 56 4b 44 8a 38 28 f5 96 dc 6b 28
   72 6d 02 21 00 fc 91 ea ed 02 16 88 66 05 4e e1 8a 2e 53 46 c4 cc 51
   fe b3 fa 10 a9 1d 2e db f9 91 25 f8 6c e6 30 0d 06 09 2a 86 48 86 f7
   0d 01 01 0b 05 00 03 82 01 01 00 14 04 3f a0 be d2 ee 3f a8 6e 3a 1f
   78 8e a0 4c 35 53 0f 11 06 1f ff 60 a1 6d 0b 83 e9 d9 2a db b3 3f 9d
   b3 d7 e0 59 4c 19 a8 e4 19 a5 0c a7 70 72 77 63 d5 fe 64 51 0a d2 7a
   d6 50 a5 8a 92 38 ec cb 2f 0f 5a c0 64 58 4d 5c 06 b9 73 63 68 27 8b
   89 34 dc 79 c7 1d 3a fd 34 5f 83 14 41 58 49 80 68 29 80 39 8a 86 72
   69 cc 79 37 ce e3 97 f7 dc f3 95 88 ed 81 03 29 00 d2 a2 c7 ba ab d6
   3a 8e ca 09 0b d9 fb 39 26 4b ff 03 d8 8e 2d 3f 6b 21 ca 8a 7d d8 5f
   fb 94 ba 83 de 9c fc 15 8d 61 fa 67 2d b0 c7 db 3d 25 0a 41 4a 85 d3
   7f 49 46 37 3c f4 b1 75 d0 52 f3 dd c7 66 f1 4b fd aa 00 ed bf e4 7e
   ed 01 ec 7b e4 f6 46 fc 31 fd 72 fe 03 d2 f2 65 af 4d 7e e2 81 9b 7a
   fd 30 3c f5 52 f4 05 34 a0 8a 3e 19 41 58 c8 a8 e0 51 71 84 09 15 ae
   ec a5 77 75 fa 18 f7 d5 77 d5 31 cc c7 2d

A.4.1.  Example: C509 Certificate Encoding

   The CBOR encoding (~C509Certificate) of the first X.509 certificate
   is shown below in CBOR diagnostic format.

   /This defines a CBOR Sequence (RFC 8742):/

   3,
   h'A6A55C870E39B40E',
   23,
   [
    -4, "US",
    -6, "Arizona",
    -5, "Scottsdale",
    -8, "Starfield Technologies, Inc.",
    -9, "http://certs.starfieldtech.com/repository/",
    -1, "Starfield Secure Certificate Authority - G2"
   ],
   1601581116,
   1635881916,
   [
     -9, "Domain Control Validated",
      1, "*.tools.ietf.org"
   ],
   0,
   h'B1E137E8EB82D689FADBF5C24B77F02C4ADE726E3E1360D1A8661EC4AD3D3260
     E5F099B5F47A7A485521EE0E3912F9CE0DCAF56961C704ED6E0F1D3B1E508879
     3A0E314116F1B1026468A5CDF54A0ACA99963508C37E275DD0A9CFF3E728AF37
     D8B67BDDF37EAE6E977FF7CA694ECCD006DF5D279B3B12E7E6FE086B527B8211



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     7C72B346EBC1E878B80FCBE1EBBD064458DC8350B2A0625BDC81B836E39E7C79
     B2A9538AE00BC94A2A13393113BD2CCFA870CF8C8D3D01A388AE1200361D1E24
     2BDD79D8530126ED284FC98694834EC8E1142E85B3AFD46EDD6946AF41250E7A
     AD8BF292CA79D97B324FF777E8F9B44F235CD45C03AED8AB3ACA135F5D5D5DA1',
   [
   -4, -2,
    8, [ 1, 2 ],
    -2, 5,
    5, "http://crl.starfieldtech.com/sfig2s1-242.crl",
    6, [ h'6086480186FD6E01071701',
        [1, "http://certificates.starfieldtech.com/repository/"],
        1,
        []
       ],
    9, [ 1, "http://ocsp.starfieldtech.com/", 2,
         "http://certificates.starfieldtech.com/repository/sfig2.crt"],
    7, h'254581685026383D3B2D2CBECD6AD9B63DB36663',
    3, [ 2, "*.tools.ietf.org", 2, "tools.ietf.org" ],
    1, h'AD8AB41C0751D7928907B0B784622F36557A5F4D',
    h'2B06010401D679020402',
    h'0481F400F2007700F65C942FD1773022145418083094568EE34D131933BFDF0C
      2F200BCC4EF164E300000174E5AC711300000403004830460221008CF54852CE
      5635433911CF10CDB91F52B33639223AD138A41DECA6FEDE1FE90F022100BCA2
      254366C19A2691C47A00B5B653ABBD44C2F8BAAEF4D2DAF2527CE64549950077
      005CDC4392FEE6AB4544B15E9AD456E61037FBD5FA47DCA17394B25EE6F6C70E
      CA00000174E5AC723C0000040300483046022100A5E0906E63E91D4FDDEFFF03
      52B91E50896007564B448A3828F596DC6B28726D022100FC91EAED0216886605
      4EE18A2E5346C4CC51FEB3FA10A91D2EDBF99125F86CE6'
   ],
   h'14043FA0BED2EE3FA86E3A1F788EA04C35530F11061FFF60A16D0B83E9D92ADB
     B33F9DB3D7E0594C19A8E419A50CA770727763D5FE64510AD27AD650A58A9238
     ECCB2F0F5AC064584D5C06B9736368278B8934DC79C71D3AFD345F8314415849
     80682980398A867269CC7937CEE397F7DCF39588ED81032900D2A2C7BAABD63A
     8ECA090BD9FB39264BFF03D88E2D3F6B21CA8A7DD85FFB94BA83DE9CFC158D61
     FA672DB0C7DB3D250A414A85D37F4946373CF4B175D052F3DDC766F14BFDAA00
     EDBFE47EED01EC7BE4F646FC31FD72FE03D2F265AF4D7EE2819B7AFD303CF552
     F40534A08A3E194158C8A8E05171840915AEECA57775FA18F7D577D531CCC72D'

   The size of the CBOR encoding (CBOR sequence) is 1295 bytes.

A.5.  Example: Certificate with Extensions IPAddrBlocks and
      IPAddrBlocksV2

   An example X.509 certificate with extensions IPAddrBlocks and
   IPAddrBlocksV2.






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   Certificate:
     Version: v3 (2)
     Serial Number:
       12:34
     Issuer: CN=selfsign-brainpoolp384r1,SURNAME=my surname,T=my title,
             GIVENNAME=my givenName,Name=my name
     Validity:
       Not Before: Thu Jan 02 01:00:00 CET 2025
       Not After : Fri Jan 02 01:00:00 CET 2026
     Subject: CN=selfsign-brainpoolp384r1,SURNAME=my surname,T=my title
              ,GIVENNAME=my givenName,Name=my name
     Subject Public Key Info:
       Public Key Algorithm: EC/BRAINPOOLP384R1
       Pub:
         04:67:09:c9:92:91:9b:49:c4:8f:d9:31:d0:5c:49:7d:38:65:
         e6:08:4c:91:df:3a:4c:7e:78:1f:41:85:43:b0:23:d5:9e:8b:
         f2:5d:13:3f:b1:a0:94:e9:d4:2c:8f:a6:ed:3b:46:e9:88:3a:
         35:ab:d4:b0:a9:d3:0a:ae:fd:9b:7e:88:ed:38:00:56:5d:1e:
         7f:06:33:13:4d:65:19:29:2d:49:bd:55:ec:30:a1:67:19:7f:
         ec:0f:74:29:82:2b:95
     X509v3 extensions:
       X509v3 keyUsage:
         digitalSignature
       X509v3 sbgp-ipAddrBlock:
         IPv4:
           192.0.2.0/24
           198.51.100.0/28
           203.0.113.0/24
         IPv6:
           2001:db8:1234::/48
           3fff:600:: - 3fff:fff:ffff:ffff:ffff:ffff:ffff:ffff
       X509v3 sbgp-ipAddrBlockV2:
         IPv4 unicast:
           192.0.2.0/24
           198.51.100.0/28
           203.0.113.0/24
         IPv6 unicast:
           2001:db8:1234::/48
           3fff:3:: - 3fff:122:0:2233:3344:5566:ffff:ffff
     Signature Algorithm: SHA384WITHECDSA
     Signature Value:
       30:64:02:30:67:09:c9:92:91:9b:49:c4:8f:d9:31:d0:5c:49:
       7d:38:65:e6:08:4c:91:df:3a:4c:7e:78:1f:41:85:43:b0:23:
       d5:9e:8b:f2:5d:13:3f:b1:a0:94:e9:d4:2c:8f:a6:ed:02:30:
       20:ed:9f:db:5a:30:9b:2c:87:04:dd:a5:f1:44:f1:7b:b3:16:
       b9:8c:29:11:24:fb:a5:cf:ec:6e:f9:7f:26:88:06:9a:e6:c5:
       2e:2b:3c:e2:23:12:8d:d1:0c:2a:a7:30




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   The DER encoding of the certificate is 717 bytes:

   30 82 02 c9 30 82 02 50 a0 03 02 01 02 02 02 12 34 30 0a 06 08 2a 86
   48 ce 3d 04 03 03 30 74 31 21 30 1f 06 03 55 04 03 0c 18 73 65 6c 66
   73 69 67 6e 2d 62 72 61 69 6e 70 6f 6f 6c 70 33 38 34 72 31 31 13 30
   11 06 03 55 04 04 0c 0a 6d 79 20 73 75 72 6e 61 6d 65 31 11 30 0f 06
   03 55 04 0c 0c 08 6d 79 20 74 69 74 6c 65 31 15 30 13 06 03 55 04 2a
   0c 0c 6d 79 20 67 69 76 65 6e 4e 61 6d 65 31 10 30 0e 06 03 55 04 29
   0c 07 6d 79 20 6e 61 6d 65 30 1e 17 0d 32 35 30 31 30 32 30 30 30 30
   30 30 5a 17 0d 32 36 30 31 30 32 30 30 30 30 30 30 5a 30 74 31 21 30
   1f 06 03 55 04 03 0c 18 73 65 6c 66 73 69 67 6e 2d 62 72 61 69 6e 70
   6f 6f 6c 70 33 38 34 72 31 31 13 30 11 06 03 55 04 04 0c 0a 6d 79 20
   73 75 72 6e 61 6d 65 31 11 30 0f 06 03 55 04 0c 0c 08 6d 79 20 74 69
   74 6c 65 31 15 30 13 06 03 55 04 2a 0c 0c 6d 79 20 67 69 76 65 6e 4e
   61 6d 65 31 10 30 0e 06 03 55 04 29 0c 07 6d 79 20 6e 61 6d 65 30 7a
   30 14 06 07 2a 86 48 ce 3d 02 01 06 09 2b 24 03 03 02 08 01 01 0b 03
   62 00 04 67 09 c9 92 91 9b 49 c4 8f d9 31 d0 5c 49 7d 38 65 e6 08 4c
   91 df 3a 4c 7e 78 1f 41 85 43 b0 23 d5 9e 8b f2 5d 13 3f b1 a0 94 e9
   d4 2c 8f a6 ed 3b 46 e9 88 3a 35 ab d4 b0 a9 d3 0a ae fd 9b 7e 88 ed
   38 00 56 5d 1e 7f 06 33 13 4d 65 19 29 2d 49 bd 55 ec 30 a1 67 19 7f
   ec 0f 74 29 82 2b 95 a3 81 b0 30 81 ad 30 0b 06 03 55 1d 0f 04 04 03
   02 07 80 30 48 06 08 2b 06 01 05 05 07 01 07 04 3c 30 3a 30 19 04 02
   00 01 30 13 03 04 00 c0 00 02 03 05 04 c6 33 64 00 03 04 00 cb 00 71
   30 1d 04 02 00 02 30 17 03 07 00 20 01 0d b8 12 34 30 0c 03 04 00 3f
   ff 06 03 04 00 3f ff 0f 30 54 06 08 2b 06 01 05 05 07 01 1c 04 48 30
   46 30 1a 04 03 00 01 01 30 13 03 04 00 c0 00 02 03 05 04 c6 33 64 00
   03 04 00 cb 00 71 30 28 04 03 00 02 01 30 21 03 07 00 20 01 0d b8 12
   34 30 16 03 05 00 3f ff 00 03 03 0d 00 3f ff 01 22 00 00 22 33 33 44
   55 66 30 0a 06 08 2a 86 48 ce 3d 04 03 03 03 67 00 30 64 02 30 67 09
   c9 92 91 9b 49 c4 8f d9 31 d0 5c 49 7d 38 65 e6 08 4c 91 df 3a 4c 7e
   78 1f 41 85 43 b0 23 d5 9e 8b f2 5d 13 3f b1 a0 94 e9 d4 2c 8f a6 ed
   02 30 20 ed 9f db 5a 30 9b 2c 87 04 dd a5 f1 44 f1 7b b3 16 b9 8c 29
   11 24 fb a5 cf ec 6e f9 7f 26 88 06 9a e6 c5 2e 2b 3c e2 23 12 8d d1
   0c 2a a7 30

A.5.1.  Example: C509 Certificate Encoding

   The CBOR encoding (~C509Certificate) of the X.509 certificate is
   shown below in CBOR diagnostic format.












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   /This defines a CBOR Sequence (RFC 8742):/

   3,
   h'1234',
   1,
   null,
   1735776000,
   1767312000,
   [
     1,"selfsign-brainpoolp384r1",
     2, "my surname",
     10, "my title",
     13, "my givenName",
     25, "my name"
   ],
   25,
   h'046709C992919B49C48FD931D05C497D3865E6084C91DF3A4C7E781F418543B0
     23D59E8BF25D133FB1A094E9D42C8FA6ED3B46E9883A35ABD4B0A9D30AAEFD9B
     7E88ED3800565D1E7F0633134D6519292D49BD55EC30A167197FEC0F7429822B
     95',
   [
     2, 1,
     32, [
          1, null, [ 29360130, 24770733054, -24770012047 ],
          2, null, [
                     316663873933876,
                     [ -316663852962606, 9 ]
                   ]
         ],
     34, [
          1, 1, [ 29360130, 24770733054, -24770012047 ],
          2, 1, [
                  h'0020010DB81234',
                  [ h'003FFF0003', h'003FFF01220000223333445566' ]
                ]
         ]
   ],
   h'6709C992919B49C48FD931D05C497D3865E6084C91DF3A4C7E781F418543B023
     D59E8BF25D133FB1A094E9D42C8FA6ED20ED9FDB5A309B2C8704DDA5F144F17B
     B316B98C291124FBA5CFEC6EF97F2688069AE6C52E2B3CE223128DD10C2AA730'











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Acknowledgments

   The authors want to thank Henk Birkholz, Mike Bishop, Mohamed
   Boucadair, Corey Bonnell, Carsten Bormann, Deb Cooley, Roman Danyliw,
   Viktor Dukhovni, Paul Hoffman, Russ Housley, Christopher Inacio, Olle
   Johansson, Benjamin Kaduk, Ted Lemon, Ilari Liusvaara, Laurence
   Lundblade, Francesca Palombini, Thomas Peterson, Michael Richardson,
   Stefan Santesson, Jim Schaad, Brian Sipos, Rene Struik, Ketan
   Talaulikar, Fraser Tweedale, Gunter Van de Velde, Éric Vyncke, and
   Paul Wouters for reviewing and commenting on intermediate versions of
   the draft.

Authors' Addresses

   John Preuß Mattsson
   Ericsson AB
   Email: john.mattsson@ericsson.com


   Göran Selander
   Ericsson AB
   Email: goran.selander@ericsson.com


   Shahid Raza
   University of Glasgow
   Email: shahid.raza@glasgow.ac.uk


   Joel Höglund
   RISE AB
   Email: joel.hoglund@ri.se


   Martin Furuhed
   IN Groupe
   Email: martin.furuhed@ingroupe.com


   Lijun Liao
   NIO
   Email: lijun.liao@nio.io









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