Conveying the More Instant Messaging Interoperability Message ID in Messaging Layer Security Additional Authenticated Data
draft-mahy-mimi-msgid-aad-01
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| Document | Type | Active Internet-Draft (individual) | |
|---|---|---|---|
| Author | Rohan Mahy | ||
| Last updated | 2025-10-16 | ||
| RFC stream | (None) | ||
| Intended RFC status | (None) | ||
| Formats | |||
| Stream | Stream state | (No stream defined) | |
| Consensus boilerplate | Unknown | ||
| RFC Editor Note | (None) | ||
| IESG | IESG state | I-D Exists | |
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draft-mahy-mimi-msgid-aad-01
More Instant Messaging Interoperability R. Mahy
Internet-Draft 16 October 2025
Intended status: Informational
Expires: 19 April 2026
Conveying the More Instant Messaging Interoperability Message ID in
Messaging Layer Security Additional Authenticated Data
draft-mahy-mimi-msgid-aad-01
Abstract
The More Instant Messaging Interoperability (MIMI) content format
defines a MIMI Message ID, communicated only to members of the
Messaging Layer Security (MLS) group in which the message was sent.
This document defines a way to share a Message ID in the MLS
Additional Authenticated Data (AAD) so it is visible to MIMI
providers.
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://rohanmahy.github.io/mimi-msgid-aad/draft-mahy-mimi-msgid-
aad.html. Status information for this document may be found at
https://datatracker.ietf.org/doc/draft-mahy-mimi-msgid-aad/.
Discussion of this document takes place on the More Instant Messaging
Interoperability 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/rohanmahy/mimi-msgid-aad.
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-
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Internet-Draft MIMI Message ID in AAD October 2025
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This Internet-Draft will expire on 19 April 2026.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Conventions and Definitions . . . . . . . . . . . . . . . . . 3
3. Mechanism . . . . . . . . . . . . . . . . . . . . . . . . . . 3
4. Security Considerations . . . . . . . . . . . . . . . . . . . 3
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 3
5.1. message_id MLS Component Type . . . . . . . . . . . . . . 3
6. Normative References . . . . . . . . . . . . . . . . . . . . 4
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 4
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 4
1. Introduction
Many messaging protocols and formats have a Message ID. The MIMI
content format defines how to calculate a MIMI Message ID (See
Section 3.3 of [I-D.ietf-mimi-content]) for an application/mimi-
content application message. A MIMI Message ID is currently only
shared end-to-end encrypted with members of the MLS [RFC9420] group
in which the message was sent. This document defines an optional
mechanism to share a Message ID in the MLS AAD, so it is visible to
intermediary providers. This greatly facilitates debugging and
troubleshooting, but causes a modest reduction in privacy.
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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. Mechanism
This document defines a new Safe AAD message_id component as
described in Section 4.9 of [I-D.ietf-mls-extensions].
When the content of an MLS application message is a MIMI content
message (media type application/mimi-content), if the message_id
component is present inside SafeAAD.aad_items, it MUST contain the
MIMI content Message ID calculated as described in Section 3.3 of
[I-D.ietf-mimi-content].
To the extent that other application formats or media types have a
Message ID, the Message ID for an application message of that type
or format MAY be conveyed in this extension, using a message ID
appropriate to the media type of the content.
4. Security Considerations
An attacker or provider with access to a fragment of message history,
and the message logs of a MIMI provider in the path of a message
could potentially learn more about the participants of a particular
MIMI room or the room's corresponding MLS group if it can see message
IDs.
5. IANA Considerations
5.1. message_id MLS Component Type
This document registers a new MLS Component Type in the Specification
Required range with the following template:
* Value: TBD (new assignment by IANA)
* Name: message_id
* Where: AD
* Recommended: Y
* Reference: RFC XXXX
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6. Normative References
[I-D.ietf-mimi-content]
Mahy, R., "More Instant Messaging Interoperability (MIMI)
message content", Work in Progress, Internet-Draft, draft-
ietf-mimi-content-07, 7 July 2025,
<https://datatracker.ietf.org/doc/html/draft-ietf-mimi-
content-07>.
[I-D.ietf-mls-extensions]
Robert, R., "The Messaging Layer Security (MLS)
Extensions", Work in Progress, Internet-Draft, draft-ietf-
mls-extensions-08, 21 July 2025,
<https://datatracker.ietf.org/doc/html/draft-ietf-mls-
extensions-08>.
[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>.
[RFC9420] Barnes, R., Beurdouche, B., Robert, R., Millican, J.,
Omara, E., and K. Cohn-Gordon, "The Messaging Layer
Security (MLS) Protocol", RFC 9420, DOI 10.17487/RFC9420,
July 2023, <https://www.rfc-editor.org/rfc/rfc9420>.
Acknowledgments
TODO acknowledge.
Author's Address
Rohan Mahy
Email: rohan.mahy@gmail.com
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