



More Instant Messaging Interoperability                       K. Kohbrok
Internet-Draft                                                 R. Robert
Intended status: Informational                               Phoenix R&D
Expires: 23 April 2026                                   20 October 2025


                            MIMI Identifiers
                   draft-kohbrok-mimi-identifiers-00

Abstract

   TODO Abstract

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://kkohbrok.github.io/draft-kohbrok-mimi-identifiers/draft-
   kohbrok-mimi-identifiers.html.  Status information for this document
   may be found at https://datatracker.ietf.org/doc/draft-kohbrok-mimi-
   identifiers/.

   Discussion of this document takes place on the More Instant Messaging
   Interoperability Working Group mailing list (mailto:mimi@ietf.org),
   which is archived at https://mailarchive.ietf.org/arch/browse/mimi/.
   Subscribe at https://www.ietf.org/mailman/listinfo/mimi/.

   Source for this draft and an issue tracker can be found at
   https://github.com/kkohbrok/draft-kohbrok-mimi-identifiers.

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 23 April 2026.




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Copyright Notice

   Copyright (c) 2025 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
   2.  Identifier types  . . . . . . . . . . . . . . . . . . . . . .   2
     2.1.  Identifiers for connection establishment  . . . . . . . .   2
     2.2.  Administrative identifiers  . . . . . . . . . . . . . . .   3
     2.3.  Display names (decorative identifiers)  . . . . . . . . .   3
   3.  Proposal for MIMI . . . . . . . . . . . . . . . . . . . . . .   4
     3.1.  Connection establishment  . . . . . . . . . . . . . . . .   4
     3.2.  Administrative identifiers  . . . . . . . . . . . . . . .   4
     3.3.  Display names . . . . . . . . . . . . . . . . . . . . . .   4
   4.  Security Considerations . . . . . . . . . . . . . . . . . . .   4
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   4
   6.  Normative References  . . . . . . . . . . . . . . . . . . . .   4
   Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . .   5
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   5

1.  Introduction

   *  MIMI currently doesn't make assumptions about names beyond the URI
      format introduced in [I-D.draft-ietf-mimi-protocol]

   *  Different messaging applications use different schemes

   *  MIMI should be able to support at least the most widely used ones

2.  Identifier types

2.1.  Identifiers for connection establishment

   *  Globally unique

   *  User-facing




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   *  Often chosen by user

   *  Multiple identifiers per user possible

   *  User can add/delete identifiers dynamically

   *  Examples:

      -  Phone numbers

      -  Signal-style usernames

      -  Matrix-style usernames

      -  Administrative identifiers

2.2.  Administrative identifiers

   *  Globally unique

   *  Generally not user-facing

   *  Generally not chosen-facing

   *  Can be provider-generated

   *  Server might not be able to link admin to connection establishment
      identifiers

   *  Immutable

   *  Examples

      -  UUIDs

      -  Matrix-style usernames

2.3.  Display names (decorative identifiers)

   *  Not globally unique

   *  Not necessarily visible to provider

   *  User-facing

   *  User-chosen





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3.  Proposal for MIMI

3.1.  Connection establishment

   *  Multiple options for connection establishment identifiers

      -  Phone numbers (draft WIP)

      -  Usernames (user chosen names, potentially with format
         restrictions)

   *  No requirement for providers to be able to link connection
      establishment identifiers with administrative identifiers

   *  Ephemeral identifiers should be allowed

3.2.  Administrative identifiers

   *  Should be unique within domain of provider

   *  Should be immutable

   *  No other requirement w.r.t. format, i.e. both Matrix-style and
      UUIDs allowed

   *  No requirement for user-readability

   *  These are used for authentication and are included in MLS
      credentials

3.3.  Display names

   *  No strict requirement for hub/provider to have access to display
      names, may be subject to policy

4.  Security Considerations

   TODO Security

5.  IANA Considerations

   This document has no IANA actions.

6.  Normative References

   [I-D.draft-ietf-mimi-protocol]
              Barnes, R., Hodgson, M., Kohbrok, K., Mahy, R., Ralston,
              T., and R. Robert, "More Instant Messaging



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              Interoperability (MIMI) using HTTPS and MLS", Work in
              Progress, Internet-Draft, draft-ietf-mimi-protocol-05, 20
              October 2025, <https://datatracker.ietf.org/doc/html/
              draft-ietf-mimi-protocol-05>.

Acknowledgments

   TODO acknowledge.

Authors' Addresses

   Konrad Kohbrok
   Phoenix R&D
   Email: konrad@ratchet.ing


   Raphael Robert
   Phoenix R&D
   Email: ietf@raphaelrobert.com
































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