[MLS] Fwd: New Version Notification for draft-kiefer-mls-light-00.txt

[Richard Barnes <[e-mail]>]

Hi MLS folks,

A few of us have been discussing how we can make MLS faster and easier for
lightweight clients, or normal clients participating in giant groups.  This
draft captures an initial proposal in that direction.

The core idea is to trade off authentication for speed: Allow clients to
join a group and participate without downloading and validating the ratchet
tree.  Obviously, such a client won't know the entire membership of the
group, and they won't be able to commit.  But as long as they know the tree
hash, they can validate log-sized proofs of membership for any given member
(e.g., themselves or the member who added them).  And with a little help
from the DS, they can process Commits and keep up with the group.

This obviously makes some interesting changes from a security analysis
point of view.  In addition to the authentication changes noted above,
allowing light clients to process Commits requires some changes to Commit
validation.  Karthik and Franziskus have already done some modeling on
this, and there are some notes in the document.

Feedback very much welcome, happy to discuss here or in Brisbane!

Best,
--Richard


---------- Forwarded message ---------
From: <[e-mail]>
Date: Mon, Mar 4, 2024 at 2:52 PM
Subject: New Version Notification for draft-kiefer-mls-light-00.txt
To: Richard L. Barnes <[e-mail]>, Joël Alwen <[e-mail]>,
Franziskus Kiefer <[e-mail]>, Karthikeyan Bhargavan <
[e-mail]>, Marta Mularczyk <[e-mail]>


A new version of Internet-Draft draft-kiefer-mls-light-00.txt has been
successfully submitted by Richard L. Barnes and posted to the
IETF repository.

Name:     draft-kiefer-mls-light
Revision: 00
Title:    Light Clients for MLS
Date:     2024-03-04
Group:    Individual Submission
Pages:    17
URL:      https://www.ietf.org/archive/id/draft-kiefer-mls-light-00.txt
Status:   https://datatracker.ietf.org/doc/draft-kiefer-mls-light/
HTML:     https://www.ietf.org/archive/id/draft-kiefer-mls-light-00.html
HTMLized: https://datatracker.ietf.org/doc/html/draft-kiefer-mls-light


Abstract:

   The Messaging Layer Security (MLS) protocol provides efficient
   asynchronous group key establishment for large groups with up to
   thousands of clients.  In MLS, any member can commit a change to the
   group, and consequently, all members must download, validate, and
   maintain the full group state which can incur a significant
   communication and computational cost, especially when joining a
   group.

   This document defines Light MLS, an extension that allows for "light
   clients".  A light client cannot commit changes to the group, and
   only has partial authentication information for the other members of
   the group, but is otherwise able to participate in the group.  In
   exchange for these limitations, a light client can participate in an
   MLS group with significantly lower requirements in terms of download,
   memory, and processing.



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