



Transport Layer Security                                 M. Usama Sardar
Internet-Draft                                                TU Dresden
Intended status: Standards Track                        25 February 2026
Expires: 29 August 2026


  Update to Post-quantum Hybrid ECDHE-MLKEM Key Agreement for TLSv1.3
                 draft-usama-tls-ecdhe-mlkem-update-00

Abstract

   This is a quick update of to-be RFC [I-D.ietf-tls-ecdhe-mlkem] for
   recommending the three hybrid key agreement mechanisms in TLS 1.3.

About This Document

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

   The latest revision of this draft can be found at https://muhammad-
   usama-sardar.github.io/tls-ecdhe-mlkem-update/draft-usama-tls-ecdhe-
   mlkem-update.html.  Status information for this document may be found
   at https://datatracker.ietf.org/doc/draft-usama-tls-ecdhe-mlkem-
   update/.

   Discussion of this document takes place on the Transport Layer
   Security Working Group mailing list (mailto:tls@ietf.org), which is
   archived at https://mailarchive.ietf.org/arch/browse/tls/.  Subscribe
   at https://www.ietf.org/mailman/listinfo/tls/.

   Source for this draft and an issue tracker can be found at
   https://github.com/muhammad-usama-sardar/tls-ecdhe-mlkem-update.

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
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   Internet-Drafts are draft documents valid for a maximum of six months
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   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 29 August 2026.



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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
   extracted from this document must include Revised BSD License text as
   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  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Motivation  . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Conventions and Definitions . . . . . . . . . . . . . . . . .   3
   3.  Security Considerations . . . . . . . . . . . . . . . . . . .   3
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   3
     4.1.  SecP256r1MLKEM768 . . . . . . . . . . . . . . . . . . . .   3
     4.2.  X25519MLKEM768  . . . . . . . . . . . . . . . . . . . . .   3
     4.3.  SecP384r1MLKEM1024  . . . . . . . . . . . . . . . . . . .   3
   5.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   4
     5.1.  Normative References  . . . . . . . . . . . . . . . . . .   4
     5.2.  Informative References  . . . . . . . . . . . . . . . . .   4
   Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . .   5
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   5

1.  Introduction

   The readers are assumed to be familiar with
   [I-D.ietf-tls-ecdhe-mlkem] and [RFC9847].

1.1.  Motivation

   Given the risk of "hardvest-now, decrypt-later" attacks
   [I-D.ietf-pquip-pqc-engineers], we believe that the hybrid key
   agreement mechanisms need to be recommended.

   Section 3 of [RFC9847] defines the meaning of "Y" in "Recommended"
   column as follows:

   |  Y: Indicates that the IETF has consensus that the item is
   |  RECOMMENDED.  This only means that the associated mechanism is fit
   |  for the purpose for which it was defined.  Careful reading of the
   |  documentation for the mechanism is necessary to understand the



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   |  applicability of that mechanism.  The IETF could recommend
   |  mechanisms that have limited applicability but will provide
   |  applicability statements that describe any limitations of the
   |  mechanism or necessary constraints on its use.

   This draft aims to build the mentioned consensus.

2.  Conventions and Definitions

   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.

3.  Security Considerations

   The security considerations of [I-D.ietf-tls-ecdhe-mlkem] apply.

4.  IANA Considerations

   This document requests the following updates to three entries in the
   TLS Supported Groups registry (https://www.iana.org/assignments/tls-
   parameters/tls-parameters.xhtml#tls-parameters-8), according to the
   procedures in Section 6 of [RFC9847].

4.1.  SecP256r1MLKEM768

   Recommended:  Y

4.2.  X25519MLKEM768

   Recommended:  Y

4.3.  SecP384r1MLKEM1024

   Recommended:  Y














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               +=======+====================+=============+
               | Value | Description        | Recommended |
               +=======+====================+=============+
               | 4587  | SecP256r1MLKEM768  | Y           |
               +-------+--------------------+-------------+
               | 4588  | X25519MLKEM768     | Y           |
               +-------+--------------------+-------------+
               | 4589  | SecP384r1MLKEM1024 | Y           |
               +-------+--------------------+-------------+

                                 Table 1

5.  References

5.1.  Normative References

   [I-D.ietf-tls-ecdhe-mlkem]
              Kwiatkowski, K., Kampanakis, P., Westerbaan, B., and D.
              Stebila, "Post-quantum hybrid ECDHE-MLKEM Key Agreement
              for TLSv1.3", Work in Progress, Internet-Draft, draft-
              ietf-tls-ecdhe-mlkem-04, 8 February 2026,
              <https://datatracker.ietf.org/doc/html/draft-ietf-tls-
              ecdhe-mlkem-04>.

   [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>.

   [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>.

5.2.  Informative References

   [I-D.ietf-pquip-pqc-engineers]
              Banerjee, A., Reddy.K, T., Schoinianakis, D., Hollebeek,
              T., and M. Ounsworth, "Post-Quantum Cryptography for
              Engineers", Work in Progress, Internet-Draft, draft-ietf-
              pquip-pqc-engineers-14, 25 August 2025,
              <https://datatracker.ietf.org/doc/html/draft-ietf-pquip-
              pqc-engineers-14>.

   [RFC9847]  Salowey, J. and S. Turner, "IANA Registry Updates for TLS
              and DTLS", RFC 9847, DOI 10.17487/RFC9847, December 2025,
              <https://www.rfc-editor.org/rfc/rfc9847>.





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Acknowledgments

   We thank the authors and contributors of [I-D.ietf-tls-ecdhe-mlkem]
   for their work.  We thank Eric Rescorla for this proposal.  We also
   thank Bas Westerbaan for the initial idea.

Author's Address

   Muhammad Usama Sardar
   TU Dresden
   Dresden
   Germany
   Email: muhammad_usama.sardar@tu-dresden.de






































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