The Messaging Layer Security (MLS) Architecture
draft-ietf-mls-architecture-01
Network Working Group E. Omara
Internet-Draft Google
Intended status: Informational B. Beurdouche
Expires: April 25, 2019 INRIA
E. Rescorla
Mozilla
S. Inguva
Twitter
A. Kwon
MIT
A. Duric
Wire
October 22, 2018
The Messaging Layer Security (MLS) Architecture
draft-ietf-mls-architecture-01
Abstract
This document describes the architecture and requirements for the
Messaging Layer Security (MLS) protocol. MLS provides a security
layer for group messaging applications with from two to a large
number of clients. It is meant to protect against eavesdropping,
tampering, and message forgery.
Status of This Memo
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This Internet-Draft will expire on April 25, 2019.
Copyright Notice
Copyright (c) 2018 IETF Trust and the persons identified as the
document authors. All rights reserved.
Omara, et al. Expires April 25, 2019 [Page 1]
Internet-Draft MLS Architecture October 2018
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. General Setting . . . . . . . . . . . . . . . . . . . . . . . 3
2.1. Group, Members and Clients . . . . . . . . . . . . . . . 5
2.2. Authentication Service . . . . . . . . . . . . . . . . . 6
2.3. Delivery Service . . . . . . . . . . . . . . . . . . . . 6
2.3.1. Key Storage . . . . . . . . . . . . . . . . . . . . . 7
2.3.2. Key Retrieval . . . . . . . . . . . . . . . . . . . . 7
2.3.3. Delivery of messages and attachments . . . . . . . . 7
2.3.4. Membership knowledge . . . . . . . . . . . . . . . . 8
2.3.5. Membership and offline members . . . . . . . . . . . 8
3. System Requirements . . . . . . . . . . . . . . . . . . . . . 9
3.1. Functional Requirements . . . . . . . . . . . . . . . . . 9
3.1.1. Asynchronous Usage . . . . . . . . . . . . . . . . . 9
3.1.2. Recovery After State Loss . . . . . . . . . . . . . . 9
3.1.3. Support for Multiple Devices . . . . . . . . . . . . 9
3.1.4. Extensibility / Pluggability . . . . . . . . . . . . 9
3.1.5. Privacy . . . . . . . . . . . . . . . . . . . . . . . 10
3.1.6. Federation . . . . . . . . . . . . . . . . . . . . . 10
3.1.7. Compatibility with future versions of MLS . . . . . . 10
3.2. Security Requirements . . . . . . . . . . . . . . . . . . 10
3.2.1. Connections between Clients and Servers (one-to-one) 10
3.2.2. Message Secrecy and Authentication . . . . . . . . . 10
4. Security Considerations . . . . . . . . . . . . . . . . . . . 13
4.1. Transport Security Links . . . . . . . . . . . . . . . . 13
4.2. Delivery Service Compromise . . . . . . . . . . . . . . . 13
4.3. Authentication Service Compromise . . . . . . . . . . . . 14
4.4. Client Compromise . . . . . . . . . . . . . . . . . . . . 14
5. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 14
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