Virtualized Conversations R. Mahy Internet-Draft Rohan Mahy Consulting Services Intended status: Informational 19 October 2025 Expires: 22 April 2026 VCON for MIMI Messages draft-ietf-vcon-mimi-messages-00 Abstract This document describes extensions to the Virtualized Conversation (VCON) syntax for instant messaging systems using the More Instant Messaging Interoperability (MIMI) content format. 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/vcon-mimi-messages/draft-ietf-vcon-mimi- messages.html. Status information for this document may be found at https://datatracker.ietf.org/doc/draft-ietf-vcon-mimi-messages/. Discussion of this document takes place on the Virtualized Conversations Working Group mailing list (mailto:vcon@ietf.org), which is archived at https://mailarchive.ietf.org/arch/browse/vcon/. Subscribe at https://www.ietf.org/mailman/listinfo/vcon/. Source for this draft and an issue tracker can be found at https://github.com/rohanmahy/vcon-mimi-messages. 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 22 April 2026. Mahy Expires 22 April 2026 [Page 1] Internet-Draft VCON for MIMI October 2025 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 . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Conventions and Definitions . . . . . . . . . . . . . . . . . 3 3. Syntax . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 3.1. Room information . . . . . . . . . . . . . . . . . . . . 4 3.2. Parties . . . . . . . . . . . . . . . . . . . . . . . . . 4 3.3. The dialog object (text type) . . . . . . . . . . . . . . 5 3.3.1. Semantics of the existing fields for text . . . . . . 5 3.3.2. Extensions to the dialog object for text . . . . . . 5 3.3.3. external_part objects . . . . . . . . . . . . . . . . 7 3.3.4. multi_part objects . . . . . . . . . . . . . . . . . 8 3.3.5. Part objects . . . . . . . . . . . . . . . . . . . . 8 3.4. Changes to the parties . . . . . . . . . . . . . . . . . 8 3.5. Attachments . . . . . . . . . . . . . . . . . . . . . . . 9 3.6. Message tombstones . . . . . . . . . . . . . . . . . . . 10 4. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . 10 4.1. MIMI examples as a VCON . . . . . . . . . . . . . . . . . 10 4.2. MIMI VCON with an Attachment . . . . . . . . . . . . . . 16 5. Security Considerations . . . . . . . . . . . . . . . . . . . 18 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 18 6.1. vCon Object Parameter Names Registry . . . . . . . . . . 18 6.2. Room object registry . . . . . . . . . . . . . . . . . . 18 6.3. Room description object registry . . . . . . . . . . . . 19 6.4. Party object . . . . . . . . . . . . . . . . . . . . . . 19 6.5. Dialog Type Name Registry . . . . . . . . . . . . . . . . 20 6.6. Dialog object types . . . . . . . . . . . . . . . . . . . 20 6.7. external_part object type . . . . . . . . . . . . . . . . 21 6.8. multi_part object type . . . . . . . . . . . . . . . . . 22 6.9. part object type . . . . . . . . . . . . . . . . . . . . 23 6.10. party_history object type . . . . . . . . . . . . . . . . 25 6.11. party_event object type . . . . . . . . . . . . . . . . . 25 6.12. attachment object type . . . . . . . . . . . . . . . . . 26 7. Normative References . . . . . . . . . . . . . . . . . . . . 26 Mahy Expires 22 April 2026 [Page 2] Internet-Draft VCON for MIMI October 2025 Appendix A. JSON Schema . . . . . . . . . . . . . . . . . . . . 27 Appendix B. Change list . . . . . . . . . . . . . . . . . . . . 27 B.1. Changes in draft-ietf-vcon-mimi-messages-00 . . . . . . . 27 B.2. Changes in draft-mahy-vcon-mimi-messages-02 . . . . . . . 27 Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 28 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 28 1. Introduction VCON [I-D.ietf-vcon-vcon-core] is a format for recording and transmitting conversations. MIMI content [I-D.ietf-mimi-content] is a format for conveying Instant Messages in an interoperable way when end-to-end encrypted. This document extends VCON, describing a way to translate a set of MIMI messages in a conversation or part of a conversation into a VCON. 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. The examples in this document may contain base64url encoded values that have extra whitespace added for readability, and to conform with Internet-Draft formatting conventions. That whitespace should be ignored. Some metadata about a MIMI content message is conveyed in the encryption protocol Messaging Layer Security (MLS) [RFC9420] or in the MIMI protocol [I-D.ietf-mimi-protocol]. For example, the sender, recipient, date, and message ID are not mandatory fields in a MIMI content message. The recipient is the MIMI room ID associated with the corresponding MLS group. The participants in the group are calculated from the MLS group state and MIMI participant list during the MLS "epoch" in which the message was sent. The sender is conveyed in MLS. The MIMI "Hub" received timestamp is conveyed in the MIMI protocol. The MIMI content message ID is constructed by hashing fields from the MIMI content, and the sender and room URIs (see Section 3.3 of [I-D.ietf-mimi-content]). The names of the parties comes from the participant list defined in Section 7.5 of [I-D.ietf-mimi-protocol], while the room metadata described in this document comes from {Section 7.6 of !I-D.ietf-mimi- protocol}}. Mahy Expires 22 April 2026 [Page 3] Internet-Draft VCON for MIMI October 2025 When message franking is enabled, as defined in Section 5.4.1 of [I-D.ietf-mimi-protocol], the franking_tag is conveyed in the MLS message's Additional Authenticated Data (AAD) field, while the MIMI protocol conveys the Frank structure generated by the MIMI Hub. 3. Syntax A MIMI conversation (or portion thereof) is represented in VCON with a mandatory list of parties and dialogs, a new top-level room object, and optionally attachment objects. 3.1. Room information This document adds a mandatory, top-level room object. It contains metadata known about the room at the start of the VCON period. * id is the MIMI room ID URL. It is mandatory. * name is the textual name of the room. It is optional. * avatar is a URL referencing the room image. It is optional. * subject is the room subject. It is optional. * mood is the room mood. It is optional * description is an array of room_description objects. It is optional. Each object can contain: - a type- a media type or an empty string. It is optional. It's default value is text/plain;charset=UTF-8. - a lang - a Language-tag as defined by [RFC5646]. It is optional. - a content - if the type begins with "text/" or is empty, the content the is UTF-8 text description of the room. Otherwise it is the base64url encoding of whatever type is described. The content field is mandatory in a room_description object. 3.2. Parties The parties array MUST contain all the participants that initiated any event in the dialog events array. It SHOULD contain all the participants that were in the participant list at any point in time during the period represented by the VCON. For example, in very large groups, it may not be necessary to include every participant that took no action. The first party in the array is the MIMI room Mahy Expires 22 April 2026 [Page 4] Internet-Draft VCON for MIMI October 2025 URI. This document adds a new party_object_type: im_uri. It is mandatory. The name field is optional. The role indicates the MIMI role and is optional. The document also adds a thumbprint party_object_type, which is the JWK thumbprint of the public key of the party. If there are multiple parties (clients) with the same im_uri then the thumbprint is required, otherwise it is optional. 3.3. The dialog object (text type) The following section refers to changes and additions to the dialog object when the type field is "text". 3.3.1. Semantics of the existing fields for text The dialog object consists of an array of instant messages of type "text". The start time is set to the hub received timestamp when available. The duration is zero. The originator is set to the parties index of the sender of the message. The message_id is the base64url encoding of the MIMI content message ID. It is mandatory. The first MIMI message represented in a MIMI VCON should contain the complete list of parties who were participants in the room at that time. For subsequent messages, a parties array consisting of index zero, indicates the recipients of the message are the active participants of the room. Changes to the roster can be tracked if party_history is present for those changes (see Section 3.4). 3.3.2. Extensions to the dialog object for text The parties array consists of the party indexes of those who were active participants when the message was sent, or zero to indicate the current membership of the room. * salt is the base64url encoding of the MIMI content salt. It is mandatory. * replaces is the base64url encoding of the MIMI content message_id of the message this message replaces. It is optional if empty. * topic_id is the base64url encoding of the MIMI topic_id. It is optional if empty. * expires is present if not null in MIMI. It contains a non- extensible object with the following items: Mahy Expires 22 April 2026 [Page 5] Internet-Draft VCON for MIMI October 2025 - relative is a boolean that is true if the time is expressed relative to the recipient read time, and false if it is expressed as an absolute date/time. It is mandatory when expires is present. - relative_time is an integer number of seconds. If relative is true, once the message has been read, the client is expected to delete the message after relative_time seconds. It is mandatory if relative is true and forbidden otherwise. - absolute_time is the expiration date/time of the message expressed as a VCON (text) date_type. It is mandatory if relative is false and forbidden otherwise. * in_reply_to is the base64url encoding of the MIMI content message_id of the message to which this message is replying (or reacting). It is optional if empty. * mimi_extensions is a base64 encoding of the CBOR MIMI content extensions map or null. It is optional if not present in the MIMI content. * franking_tag is a base64url encoding of the MIMI franking_tag, or null. It is optional if not present. * frank is a base64url encoding of the MIMI protocol Frank TLS struct, or null. It is optional if not present. * disposition - optional if set to the default value ("render"). Refers to the overall disposition of the entire message. * language - optional if absent. Refers to the language of the entire message. VCON typically expresses message content using the body, encoding, and mediatype fields. In order to preserve this convention we use these fields directly for a MIMI SinglePart structure, but use new multi_part and external_part objects for the MultiPart and ExternalPart MIMI structures, respectively. If the message contains a single MIMI ExternalPart, the dialog object contains an external_part object. If the message contains multiple parts (a MIMI MultiPart), the dialog object contains a multi_part object. If there is only a single part in the message, there is no Part object. The part has a virtual part_index of 0, which is not transmitted. Mahy Expires 22 April 2026 [Page 6] Internet-Draft VCON for MIMI October 2025 A MIMI message with a NullPart has no body, encoding, or mediatype fields. 3.3.3. external_part objects The external_part object can contain the following fields with similar meanings to those in MIMI content, with exceptions noted below. * mediatype is the value of the contentType in MIMI. It is mandatory if present in the MIMI message and recommended otherwise. No mediatype is present in the dialog object. * url is the URL of the content as a text string. It is mandatory * expires is a date_type (text) date. It is optional if not present. * size is an integer number of octets. It is optional if not present. * description is a text string. It is optional if not present. * filename is a text string. It is optional if not present. * content_hash is the base64url encoded string of the MIMI contentHash of the ExternalPart, prefixed with the name of the hash algorithm corresponding to hashAlg and a colon (for example "sha256:"). content_hash is mandatory if it was included in the MIMI content ExternalPart, and omitted otherwise. In addition, the following fields are unique to MIMI VCON. * cached is a boolean. It is mandatory if it is true, which means that a copy of the external content is available in a vcon attachment object (see Section 3.5). If cache is true and no content_hash is present, a new content hash is calculated for the attachment and placed the cache_ref field (which can only be present in this case). external_part has several fields for the decryption of the referenced content. If it is not necessary to reconstruct the original MIMI content (for example to allow later verification of the message ID), these fields can be omitted once the content has been downloaded, decrypted, verified, and included in the VCON attachments array. Otherwise they are mandatory if present in the MIMI content. All of these fields are base64url encoded strings. Mahy Expires 22 April 2026 [Page 7] Internet-Draft VCON for MIMI October 2025 * enc_alg * key * nonce * aad 3.3.4. multi_part objects A multi_part object is designed to carry multiple items, as with the MultiPart structure in MIMI content or the top level multipart media types. It contains the following fields. * part_semantics is one of "chooseOne", "singleUnit", or "processAll". It is mandatory. * parts is an array of Part objects. It is mandatory in a multi_part object. 3.3.5. Part objects The following fields can be in a Part object. They have the same meaning as their MIMI content counterparts. * disposition optional if set to the default value ("render"). It refers to a specific part. * language - optional if absent. It refers to a specific part. * part_index is an unsigned integer. It is mandatory. * cardinality is one of "nullpart", "single", "external", or "multi". mandatory. If cardinality is "single", then body, encoding, and mediatype fields are included directly in the Part object. If cardinality is "external" or "multi", an external_part or multi_part object is included, respectively. 3.4. Changes to the parties The party_history object can be interleaved with text objects in the dialog objects array. It indicates when changes have been made to the participants represented by party index zero, as well as properties of individual parties (such as their role or name). The party_history object contains the following fields. Mahy Expires 22 April 2026 [Page 8] Internet-Draft VCON for MIMI October 2025 * party is the party index of the modified party. It is mandatory. * originator is the party that originated the change. It is optional. * time is the time that the change was effected * event is the type of change. It is mandatory and for MIMI VCONs can be one of the following new event types: - add: user added by someone else - self_add: user added herself directly - leave: user leaves of their own accord - remove: user is removed by another user - ban: user is banned from the group - update: user or client is updated - room: room metadata was updated * name is the new name of the user. It is only permitted for an update event. * role is the new role assigned to the user. It is only permitted for an update event. * room is a new room object containing the new room metadata. It is only permitted for an event of type room. The updated room object can contain anything in the top-level room object except for the id field (which MUST NOT be present). When the room metadata is changed, the party field is set to 0. 3.5. Attachments An attachment consists of the following fields: * start: is the time when the attachment was downloaded. It is mandatory. * party: is the party that downloaded the attachment. It is mandatory. Mahy Expires 22 April 2026 [Page 9] Internet-Draft VCON for MIMI October 2025 * content_hash: is the base64url encoded hash using the hash name prefixed with a colon before the hash (ex: "sha256:"). It is mandatory. * dialog_object_ref is a string consisting of: "mid:" (representing the message ID URI), the message_id of the message in the dialog object, a colon, the part_index of the Part (or "0" if the ExternalPart is at the top level), and the string "@anon.invalid" The mediatype, filename, encoding, and body fields are as they are defined in VCON and are all mandatory. 3.6. Message tombstones When a message has been deleted/retracted, or it expires, it can be valuable to present a record that such a message was previously present, by generating a dialog object with the following fields (which are all mandatory): * type is "tombstone" * start is the time the tombstone was generated * message_id is the message ID of the message. * status is the status of the former message, either "retracted" or "expired". 4. Examples 4.1. MIMI examples as a VCON The example vcon consists of the example messages from Section 5 of the MIMI content specification plus a party_history object adding two new participants, and a single multipart message at the end. { "vcon": "0.0.1", "room": { "id": "mimi://example.com/r/engineering_team", "name": "Engineering Team", "avatar": "https://example.com/images/tHMqLMAkmCzNmweL", "subject": None, "mood": None, "description": [ {"type":"", "lang":"en", "content":"Engineering Team Internal Chat"}, { "type":"", "lang":"fr", Mahy Expires 22 April 2026 [Page 10] Internet-Draft VCON for MIMI October 2025 "content":"Chat de l'équipe interne des ingénieurs" } ] } "parties": [ { "im_uri": "mimi://example.com/r/engineering_team", }, { "im_uri": "mimi://example.com/u/alice-smith", "name": "Alice Smith", "role": "moderator", "thumbprint": "TODOFIXDZXCog_FfQp-xLemZkD5GKB9H7Z-Y41O4jEw" }, { "im_uri": "mimi://example.com/u/bob-jones", "name": "Bob Jones", "role": "member", "thumbprint": "TODOFIXYUFE7bV9pXAHZHi5bwSWzLJqjncevs9aLKDg" }, { "im_uri": "mimi://example.com/u/cathy-washington", "name": "Cathy Washington", "role": "member", "thumbprint": "TODOFIXzH3EeOGbI0-oiDGTXlgKmkMzQyQ2W_Y-TB1U" }, { "im_uri": "mimi://example.com/u/doug-king", "name": "Doug King", "role": "member", "thumbprint": "TODOFIX3fdpORnHwncbdOS5XieH-z1m5r61u14WyNkj" }, { "im_uri": "mimi://example.com/u/liz-roberts", "name": "Elizabeth Roberts", "role": "member", "thumbprint": "TODOFIX7qR7oFriyKfKgIJ43ZdANoObICqH0kN9g82J" } ], "dialog": [ { "type": "text", "start": "2022-02-08T22:13:45.019-00:00", "duration": 0, "parties": [ 1, 2, 3 ], "franking_tag": null, Mahy Expires 22 April 2026 [Page 11] Internet-Draft VCON for MIMI October 2025 "frank": null, "originator": 1, "salt": "PC16IkqDbGRiffzjeyPKIg" "message_id": "AbAIRGcnPMQ9bw6-rBPrhCKcT__o9sNZTJBfR3eeWnk", "mimi_extensions": "oQGiAXgrbWltaTovL2h1Yi5leGFtcGxlL3IvU mwzM0ZXTENZV093eEhyWW5wV0RRZwJ4GG1pbWk6Ly9iLmV4YW1wbG UvdS9hbGljZQ", "mimetype": "text/markdown;variant=GFM", "encoding": "none" "body": "Hi everyone, we just shipped release 2.0. __Good work__!", }, { "type": "text", "start": "2022-02-08T22:13:57.492-00:00", "duration": 0, "parties": [ 0 ], "originator": 2, "salt": "PVeWNQrjJej4AjhqkGlSkw" "message_id": "AaQZrvThbUPPwGwoI17Pvp-uvHQNAUjnyiCyIVCTCDY", "in_reply_to": "AbAIRGcnPMQ9bw6-rBPrhCKcT__o9sNZTJBfR3eeWnk", "mimetype": "text/markdown;variant=GFM", "encoding": "none" "body": "Right on! _Congratulations_ \'all!", }, { "type": "text", "start": "2022-02-08T22:13:57.728-00:00", "duration": 0, "parties": [ 0 ], "originator": 3, "salt": "lV7CoeiFmX4ALPSKOdrR0w" "message_id": "AbGhSoj0SA4TNr6GmHhU-Dij7IKUTUUz2NQIhXhVDtc", "in_reply_to": "AbAIRGcnPMQ9bw6-rBPrhCKcT__o9sNZTJBfR3eeWnk", "disposition": "reaction", "mimetype": "text/plain;charset=utf-8", "encoding": "none" "body": "❤", }, { "type": "text", Mahy Expires 22 April 2026 [Page 12] Internet-Draft VCON for MIMI October 2025 "start": "2022-02-08T22:14:03.008-00:00", "duration": 0, "parties": [ 0 ], "originator": 3, "salt": "pkL5Tr0pLla5EiLUOfVDJw" "message_id": "rF4iS5BcJ-aFfisoFDCrnTE9pZZBGCxGCoXGJ9VXnck", "mimetype": "text/markdown;variant=GFM", "encoding": "none" "body": "Kudos to [@Alice Smith](mimi://example.com/alice-smith) for making the release happen!", }, { "type": "text", "start": "2022-02-08T22:14:08.621-00:00", "duration": 0, "parties": [ 0 ], "originator": 2, "salt": "26QI8adeG9TDfPvh-j1Stg" "message_id": "-GqJXuoaJu1Xosu-N8nt6NWzA2RLmIRY0q9jf_kvWkM", "replaces": "AaQZrvThbUPPwGwoI17Pvp-uvHQNAUjnyiCyIVCTCDY", "in_reply_to": "AbAIRGcnPMQ9bw6-rBPrhCKcT__o9sNZTJBfR3eeWnk", "mimetype": "text/markdown;variant=GFM", "encoding": "none" "body": "Right on! _Congratulations_ y'all" }, { "type": "text", "start": "2022-02-08T22:14:08.621-00:00", "duration": 0, "parties": [ 0 ], "originator": 2, "salt": "HbkjCnTRrhn84LPT86VvYg" "message_id": "8cqo1B9IA6nnB63oPEnmWxIqr7uk7WvQTBgVVlD_Q2c", "replaces": "AaQZrvThbUPPwGwoI17Pvp-uvHQNAUjnyiCyIVCTCDY", "in_reply_to": "AbAIRGcnPMQ9bw6-rBPrhCKcT__o9sNZTJBfR3eeWnk" }, { "party_history": [ { Mahy Expires 22 April 2026 [Page 13] Internet-Draft VCON for MIMI October 2025 "party": 4, "event": "add", "originator": 1, "time": "2022-02-08T22:14:09.277-00:00" }, { "party": 5, "event": "add", "originator": 1, "time": "2022-02-08T22:14:09.277-00:00" } ] }, { "type": "text", "start": "2022-02-08T22:14:10.389-00:00", "duration": 0, "parties": [ 0 ], "originator": 3, "salt": "IrAeojgZcZGiQjjBbmqVhw" "message_id": "bYZ2NHaryq0WS2pq5IE9fMc4zltUyE6WrKJ7bNB5tMc", "replaces": "AaQZrvThbUPPwGwoI17Pvp-uvHQNAUjnyiCyIVCTCDY", "in_reply_to": "AbAIRGcnPMQ9bw6-rBPrhCKcT__o9sNZTJBfR3eeWnk", "disposition": "reaction" }, { "type": "text", "start": "2022-02-08T22:49:06.227-00:00", "duration": 0, "parties": [ 0 ], "originator": 1, "salt": "8xnQi9hjVw4N8cRGEm4X1A" "message_id": "GkblzkXJxyar0lTgkfcMQ0wo8qpbcU0MqtTg-gM1FiY", "expiring": { "relative": false, "expires": "2022-02-08T22:59:06.227-00:00" }, "status": "expired" }, { "type": "text", "start": "2022-02-08T22:53:41.134-00:00", Mahy Expires 22 April 2026 [Page 14] Internet-Draft VCON for MIMI October 2025 "duration": 0, "parties": [ 0 ], "originator": 2, "salt": "bqhJBqYaTyDmgTj-QtdZPA" "message_id": "Tdt8UCUl1ugSLRmuObvib_4bvu_Hz3NSwaYuy-TtET4", "disposition": "attachment", "language": "en", "external_part": { "mimetype": "video/mp4", "url": "https://example.com/storage/8ksB4bSrrRE.mp4", "size": 708234961, "description": "2 hours of key signing video", "filename": "bigfile.mp4", "content_hash": "sha256:OczZYpW_L0B1DsMSLJqL2jTRJKoj7fTUJ2jhnX70-00", "enc_alg": 1, "key": "aZISOs306M7n_3csR-J1cw", "nonce": "5VM0QcZI3PNmnquV6CUgxg", "aad": "" } }, { "type": "text", "start": "2022-02-08T22:54:09.972-00:00", "duration": 0, "parties": [ 0 ], "originator": 3, "salt": "dPEJAGOdZGeX6_OCp0RUzA" "message_id": "KgDTc29ZP4YyYmXtaYyxpZNrnigjvCjrCYuLTz19zWc", "disposition": "session", "external_part": { "url": "https://example.com/join/12345", "description": "Join the Foo 118 conference" } }, { "type": "text", "start": "2022-02-08T22:57:14.084-00:00", "duration": 0, "parties": [ 0 ], "originator": 1, Mahy Expires 22 April 2026 [Page 15] Internet-Draft VCON for MIMI October 2025 "salt": "YSbs-8jeoXfI6Z4lQRUWQw" "message_id": "sD19bKRmu4mA9SHznfQOLQQzKnx1Q4mEtSNQhvzqCZw", "disposition": "render", "part_index": 0, "multi_part": { "part_semantics": "chooseOne", "parts": [ { "disposition": "render", "language": "en", "part_index": 1, "mediatype": "text/markdown;variant=GFM", "encoding": "none" "body": "Hello!" }, { "disposition": "render", "language": "fr", "part_index": 2, "mimetype": "text/markdown;variant=GFM", "encoding": "none" "body": "Bonjour!" } ] } }, ] } 4.2. MIMI VCON with an Attachment This example vcon consists of a single message in a dialog which references an attachment. { "vcon": "0.0.1", "room": { "id": "mimi://example.com/r/engineering_team", "name": "Engineering Team", } "parties": [ { "imUri": "mimi://example.com/r/engineering_team", }, { "im_uri": "mimi://example.com/u/alice-smith", "name": "Alice Smith", "role": "moderator", Mahy Expires 22 April 2026 [Page 16] Internet-Draft VCON for MIMI October 2025 "thumbprint": "TODOFIXDZXCog_FfQp-xLemZkD5GKB9H7Z-Y41O4jEw" }, { "im_uri": "mimi://example.com/u/bob-jones", "name": "Bob Jones", "role": "member", "thumbprint": "TODOFIXYUFE7bV9pXAHZHi5bwSWzLJqjncevs9aLKDg" }, { "im_uri": "mimi://example.com/u/cathy-washington", "name": "Cathy Washington", "role": "member", "thumbprint": "TODOFIXzH3EeOGbI0-oiDGTXlgKmkMzQyQ2W_Y-TB1U" } ], "dialog": [ { "type": "text", "start": "2022-02-08T22:53:41.134-00:00", "duration": 0, "parties": [ 0, 1, 2, 3 ], "originator": 1, "salt": "jaPfwAWReuvBdfayWkSvtQ" "message_id": "Tdt8UCUl1ugSLRmuObvib_4bvu_Hz3NSwaYuy-TtET4", "disposition": "attachment", "language": "en", "external_part": { "mediatype": "video/mp4", "url": "https://example.com/storage/8ksB4bSrrRE.mp4", "size": 708234961, "description": "2 hours of key signing video", "filename": "bigfile.mp4", "content_hash": "sha256:OczZYpW_L0B1DsMSLJqL2jTRJKoj7fTUJ2jhnX70-00", "cached": true } }, ], "attachments": [ { "start": "2022-02-08T22:53:41.134-00:00", "party": 1, "content_hash": "sha256:OczZYpW_L0B1DsMSLJqL2jTRJKoj7fTUJ2jhnX70-00", "dialog_object_ref": "mid:Tdt8UCUl1ugSLRmuObvib_4bvu_Hz3NSwaYuy-TtET4:0@anon.invalid", Mahy Expires 22 April 2026 [Page 17] Internet-Draft VCON for MIMI October 2025 "mediatype": "video/mp4", "filename": "bigfile.mp4", "encoding": "base64url", "body": "Ma0hHSr0f_iUk_RSShTgtY...nSQbZEip5danJYQqsvwWQ" } ] } 5. Security Considerations TODO Security 6. IANA Considerations This document requests IANA to add following entries under the relevant registries in the vCon JSON Objects Group. IANA, please replace RFCXXXX with the number of this document. 6.1. vCon Object Parameter Names Registry +======+===========================+================+=============+ | Name | Description | Change Control | Reference | +======+===========================+================+=============+ | room | metadata about an instant | IETF | Section 3.1 | | | messaging room or channel | | of RFCXXXX | +------+---------------------------+----------------+-------------+ Table 1 6.2. Room object registry +=============+=====================+================+=============+ | Name | Description | Change Control | Reference | +=============+=====================+================+=============+ | id | room ID | IETF | Section 3.1 | | | | | RFCXXXX | +-------------+---------------------+----------------+-------------+ | name | The human-readable | IETF | Section 3.1 | | | name of the room | | RFCXXXX | +-------------+---------------------+----------------+-------------+ | avatar | An image associated | IETF | Section 3.1 | | | with the room | | RFCXXXX | +-------------+---------------------+----------------+-------------+ | subject | The subject of the | IETF | Section 3.1 | | | room | | RFCXXXX | +-------------+---------------------+----------------+-------------+ | mood | The mood of the | IETF | Section 3.1 | Mahy Expires 22 April 2026 [Page 18] Internet-Draft VCON for MIMI October 2025 | | room | | RFCXXXX | +-------------+---------------------+----------------+-------------+ | description | The description of | IETF | Section 3.1 | | | the room | | RFCXXXX | +-------------+---------------------+----------------+-------------+ Table 2 6.3. Room description object registry This documents creates a new Room description object registry under the vCon JSON Objects Group. It has the following values. +=========+========================+================+=============+ | Name | Description | Change Control | Reference | +=========+========================+================+=============+ | type | an optional media type | IETF | Section 3.1 | | | of the description | | RFCXXXX | +---------+------------------------+----------------+-------------+ | lang | the language of the | IETF | Section 3.1 | | | description | | RFCXXXX | +---------+------------------------+----------------+-------------+ | content | the content of the | IETF | Section 3.1 | | | description | | RFCXXXX | +---------+------------------------+----------------+-------------+ Table 3 6.4. Party object +============+==============================+=========+=============+ | Name | Description | Change | Reference | | | | Control | | +============+==============================+=========+=============+ | im_uri | The URI of an instant | IETF | Section 3.2 | | | messaging users or room | | RFCXXXX | +------------+------------------------------+---------+-------------+ | role | The role of an instant | IETF | Section 3.2 | | | messaging user | | RFCXXXX | +------------+------------------------------+---------+-------------+ +------------+------------------------------+---------+-------------+ | thumbprint | The public key | IETF | Section 3.2 | | | thumbprint of an instant | | RFCXXXX | | | messaging client | | | +------------+------------------------------+---------+-------------+ Table 4 Mahy Expires 22 April 2026 [Page 19] Internet-Draft VCON for MIMI October 2025 6.5. Dialog Type Name Registry +===========+==========================+=========+===========+ | Name | Description | Change | Reference | | | | Control | | +===========+==========================+=========+===========+ | tombstone | a placeholder for an no | IETF | Section | | | longer available message | | 3.6 | | | (ex: deleted, expired) | | RFCXXXX | +-----------+--------------------------+---------+-----------+ Table 5 6.6. Dialog object types +=================+===========================+=========+===========+ | Name | Description | Change | Reference | | | | Control | | +=================+===========================+=========+===========+ | salt | The message salt | IETF | Section | | | | | 3.3.2 | | | | | RFCXXXX | +-----------------+---------------------------+---------+-----------+ | replaces | The message_id of | IETF | Section | | | another message this | | 3.3.2 | | | message replaces | | RFCXXXX | +-----------------+---------------------------+---------+-----------+ | expires | When this message | IETF | Section | | | expires | | 3.3.2 | | | | | RFCXXXX | +-----------------+---------------------------+---------+-----------+ | in_reply_to | The message_id of | IETF | Section | | | another message to | | 3.3.2 | | | which this message | | RFCXXXX | | | replies or reacts | | | +-----------------+---------------------------+---------+-----------+ | mimi_extensions | A map of any | IETF | Section | | | mimi_extensions | | 3.3.2 | | | associated with this | | RFCXXXX | | | message | | | +-----------------+---------------------------+---------+-----------+ | franking_tag | The sender-asserted | IETF | Section | | | franking_tag | | 3.3.2 | | | | | RFCXXXX | +-----------------+---------------------------+---------+-----------+ | frank | The frank data | IETF | Section | | | structure returned | | 3.3.2 | | | by the MIMI server | | RFCXXXX | Mahy Expires 22 April 2026 [Page 20] Internet-Draft VCON for MIMI October 2025 | | with the message | | | +-----------------+---------------------------+---------+-----------+ | disposition | The disposition of | IETF | Section | | | the message content | | 3.3.2 | | | | | RFCXXXX | +-----------------+---------------------------+---------+-----------+ | language | The language of the | IETF | Section | | | message content | | 3.3.2 | | | | | RFCXXXX | +-----------------+---------------------------+---------+-----------+ | status | The status of a | IETF | Section | | | former message | | 3.6 | | | | | RFCXXXX | +-----------------+---------------------------+---------+-----------+ | multi_part | A multi_part object | IETF | Section | | | containing the | | 3.3.4 | | | content | | RFCXXXX | +-----------------+---------------------------+---------+-----------+ | external_part | An external_part | IETF | Section | | | object referencing | | 3.3.3 | | | out-of-band content | | RFCXXXX | +-----------------+---------------------------+---------+-----------+ Table 6 6.7. external_part object type This documents creates a new External_part object registry under the vCon JSON Objects Group. It has the following values. +==============+===========================+=========+===========+ | Name | Description | Change | Reference | | | | Control | | +==============+===========================+=========+===========+ | mediatype | the media type of the | IETF | Section | | | externally referenced | | 3.3.3 | | | content | | RFCXXXX | +--------------+---------------------------+---------+-----------+ | url | the url of the externally | IETF | Section | | | referenced content | | 3.3.3 | | | | | RFCXXXX | +--------------+---------------------------+---------+-----------+ | size | the size in bytes of the | IETF | Section | | | externally referenced | | 3.3.3 | | | content | | RFCXXXX | +--------------+---------------------------+---------+-----------+ | description | the description of the | IETF | Section | | | externally referenced | | 3.3.3 | Mahy Expires 22 April 2026 [Page 21] Internet-Draft VCON for MIMI October 2025 | | content | | RFCXXXX | +--------------+---------------------------+---------+-----------+ | filename | the filename of the | IETF | Section | | | externally referenced | | 3.3.3 | | | content | | RFCXXXX | +--------------+---------------------------+---------+-----------+ | content_hash | a representation of the | IETF | Section | | | MIMI contentHash and | | 3.3.3 | | | hashAlg of the externally | | RFCXXXX | | | referenced content | | | +--------------+---------------------------+---------+-----------+ | cached | whether the referenced | IETF | Section | | | content is cached | | 3.3.3 | | | | | RFCXXXX | +--------------+---------------------------+---------+-----------+ | enc_alg_ | the encryption algorithm | IETF | Section | | | used to encrypt the | | 3.3.3 | | | externally referenced | | RFCXXXX | | | content | | | +--------------+---------------------------+---------+-----------+ | key | the encryption key of the | IETF | Section | | | externally referenced | | 3.3.3 | | | content | | RFCXXXX | +--------------+---------------------------+---------+-----------+ | nonce | the encryption nonce of | IETF | Section | | | the externally referenced | | 3.3.3 | | | content | | RFCXXXX | +--------------+---------------------------+---------+-----------+ | aad | the media type of the | IETF | Section | | | externally referenced | | 3.3.3 | | | content | | RFCXXXX | +--------------+---------------------------+---------+-----------+ Table 7 6.8. multi_part object type This documents creates a new Multi_part object registry under the vCon JSON Objects Group. It has the following values. Mahy Expires 22 April 2026 [Page 22] Internet-Draft VCON for MIMI October 2025 +================+=======================+=========+===========+ | Name | Description | Change | Reference | | | | Control | | +================+=======================+=========+===========+ | part_semantics | How multiple parts in | IETF | Section | | | the same multi_part | | 3.3.4 | | | object are handled | | RFCXXXX | +----------------+-----------------------+---------+-----------+ | parts | An array of part | IETF | Section | | | objects | | 3.3.4 | | | | | RFCXXXX | +----------------+-----------------------+---------+-----------+ Table 8 6.9. part object type This documents creates a new Part object registry under the vCon JSON Objects Group. It has the following values. Mahy Expires 22 April 2026 [Page 23] Internet-Draft VCON for MIMI October 2025 +===============+============================+=========+===========+ | Name | Description | Change | Reference | | | | Control | | +===============+============================+=========+===========+ | disposition | The disposition of the | IETF | Section | | | message part | | 3.3.5 | | | | | RFCXXXX | +---------------+----------------------------+---------+-----------+ | language | The language of the | IETF | Section | | | message part | | 3.3.5 | | | | | RFCXXXX | +---------------+----------------------------+---------+-----------+ | part_index | The relative index of the | IETF | Section | | | part within the message | | 3.3.5 | | | | | RFCXXXX | +---------------+----------------------------+---------+-----------+ | cardinality | one of "nullpart", | IETF | Section | | | "single", "external", or | | 3.3.5 | | | "multi" | | RFCXXXX | +---------------+----------------------------+---------+-----------+ | mediatype | The media type of the part | IETF | Section | | | | | 3.3.5 | | | | | RFCXXXX | +---------------+----------------------------+---------+-----------+ | encoding | The encoding of the | IETF | Section | | | message part (as in | | 3.3.5 | | | Section 2.3.1 of | | RFCXXXX | | | [I-D.ietf-vcon-vcon-core]) | | | +---------------+----------------------------+---------+-----------+ | body | The content of the message | IETF | Section | | | part | | 3.3.5 | | | | | RFCXXXX | +---------------+----------------------------+---------+-----------+ | multi_part | A multi_part object | IETF | Section | | | containing more parts of | | 3.3.4 | | | the content | | RFCXXXX | +---------------+----------------------------+---------+-----------+ | external_part | An external_part object | IETF | Section | | | referencing out-of-band | | 3.3.3 | | | content | | RFCXXXX | +---------------+----------------------------+---------+-----------+ Table 9 Mahy Expires 22 April 2026 [Page 24] Internet-Draft VCON for MIMI October 2025 6.10. party_history object type +============+=============================+=========+=============+ | Name | Description | Change | Reference | | | | Control | | +============+=============================+=========+=============+ | originator | which party index initiated | IETF | Section 3.4 | | | this party_history event | | RFCXXXX | +------------+-----------------------------+---------+-------------+ | name | the name of the party that | IETF | Section 3.4 | | | initiated this | | RFCXXXX | | | party_history event | | | +------------+-----------------------------+---------+-------------+ | role | the role of the party that | IETF | Section 3.4 | | | initiated this | | RFCXXXX | | | party_history event | | | +------------+-----------------------------+---------+-------------+ | room | a room object containing | IETF | Section 3.4 | | | updated room metadata | | RFCXXXX | +------------+-----------------------------+---------+-------------+ Table 10 6.11. party_event object type +===========+==========================+=========+=============+ | Name | Description | Change | Reference | | | | Control | | +===========+==========================+=========+=============+ | add | indicates the party was | IETF | Section 3.4 | | | added by someone else | | RFCXXXX | +-----------+--------------------------+---------+-------------+ | self_add_ | indicates the party was | IETF | Section 3.4 | | | added by itself | | RFCXXXX | +-----------+--------------------------+---------+-------------+ | leave | indicates the party left | IETF | Section 3.4 | | | of their own accord | | RFCXXXX | +-----------+--------------------------+---------+-------------+ | remove | indicates the party was | IETF | Section 3.4 | | | removed by someone else | | RFCXXXX | +-----------+--------------------------+---------+-------------+ | ban | indicates the party was | IETF | Section 3.4 | | | banned | | RFCXXXX | +-----------+--------------------------+---------+-------------+ | update | indicates the party | IETF | Section 3.4 | | | changed | | RFCXXXX | +-----------+--------------------------+---------+-------------+ | room | indicates room metadata | IETF | Section 3.4 | Mahy Expires 22 April 2026 [Page 25] Internet-Draft VCON for MIMI October 2025 | | changed | | RFCXXXX | +-----------+--------------------------+---------+-------------+ Table 11 6.12. attachment object type +===================+===================+=========+===========+ | Name | Description | Change | Reference | | | | Control | | +===================+===================+=========+===========+ | dialog_object_ref | the message_id of | IETF | Section | | | the dialog object | | 3.5 | | | referencing this | | RFCXXXX | | | attachment | | | +-------------------+-------------------+---------+-----------+ Table 12 7. 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, . [I-D.ietf-mimi-protocol] Barnes, R., Hodgson, M., Kohbrok, K., Mahy, R., Ralston, T., and R. Robert, "More Instant Messaging Interoperability (MIMI) using HTTPS and MLS", Work in Progress, Internet-Draft, draft-ietf-mimi-protocol-04, 7 July 2025, . [I-D.ietf-vcon-vcon-core] Petrie, D., "The JSON format for vCon - Conversation Data Container", Work in Progress, Internet-Draft, draft-ietf- vcon-vcon-core-01, 15 October 2025, . [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . Mahy Expires 22 April 2026 [Page 26] Internet-Draft VCON for MIMI October 2025 [RFC5646] Phillips, A., Ed. and M. Davis, Ed., "Tags for Identifying Languages", BCP 47, RFC 5646, DOI 10.17487/RFC5646, September 2009, . [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, . [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, . Appendix A. JSON Schema *TODO* Appendix B. Change list B.1. Changes in draft-ietf-vcon-mimi-messages-00 * adopted as a WG item * added IANA registrations under the new framework * fixed an inconsistency with disposition and language tags not consistent with MIMI content * including all parties in the participant list is now a SHOULD * room metadata changes are now expressed as a party_history event * expires is not not present unless it was present in MIMI. Only either absolute_time or relative_time is allowed. * updated references * refactor to use the new message_id field name from core * more case adjustments B.2. Changes in draft-mahy-vcon-mimi-messages-02 * adjust to make consistent with new syntax of MIMI content (add salt, removed lastSeen, in_reply_to is just a message id, expires is an object to handle relative expiration, added mimi_extensions). Mahy Expires 22 April 2026 [Page 27] Internet-Draft VCON for MIMI October 2025 * use a different field from content_hash when attaching an ExternalPart that did not have a hash in the MIMI message. * allow the parties list of 0 to indicate sending to every active participant in the room. * added a description of using party_history to track changes to the participant list. * added room metadata, and a way to modify it * added support for message "tombstones" * use mediatype instead of mimetype throughout * make the case of field names more consistent Acknowledgments TODO acknowledge. Author's Address Rohan Mahy Rohan Mahy Consulting Services Email: rohan.ietf@gmail.com Mahy Expires 22 April 2026 [Page 28]