[km-fs-pcs] No ciphersuite negotiation in MLS-TLS with 2-party profile
Gaëtan Wattiau <gaetan.wattiau@proton.me> Thu, 25 June 2026 13:38 UTC
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Date: Thu, 25 Jun 2026 13:37:53 +0000
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From: Gaëtan Wattiau <gaetan.wattiau@proton.me>
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Subject: [km-fs-pcs] No ciphersuite negotiation in MLS-TLS with 2-party profile
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The [2-party profile](https://datatracker.ietf.org/doc/draft-kohbrok-mls-two-party-profile/00/) or [MLS-TLS](https://datatracker.ietf.org/doc/draft-kohbrok-mls-tls/00/) drafts don't support ciphersuite negotiation. The only mention of it is in §3: > The responder inspects the KeyPackage and checks whether it supports > the offered ciphersuite and whether the initiator has sufficient > capabilities to support the connection. Problems: - It doesn't define an error path if the ciphersuite isn't supported by the server. - It doesn't offer any indication of what to do when there is an error. - It doesn't define any efficient negotiation system. Best, Gaëtan Wattiau
- [km-fs-pcs] No ciphersuite negotiation in MLS-TLS… Gaëtan Wattiau
- [km-fs-pcs] Re: No ciphersuite negotiation in MLS… Konrad Kohbrok