[TLS] WG Last Call: draft-ietf-tls-mlkem-08 (Ends 2026-07-08)

[Joseph Salowey via Datatracker <[e-mail]>]

This message initiates a new Working Group Last Call for draft-ietf-tls-mlkem[1], which defines standalone ML-KEM key establishment for TLS 1.3. The main question before the working group is: "Should the working group publish a document specifying stand alone ML-KEM?". If there is rough consensus then we will push to refine and publish the document; otherwise, we will stop discussing the draft and not progress it. Please respond to this call indicating whether you support publishing a document specifying a stand alone ML-KEM. Please refrain from further discussion on this topic as most arguments have been discussed multiple times.

Why are we holding this consensus call now?

Significant developments have occurred both within this document and in the broader TLS ecosystem to address the concerns raised in the last WGLC. Therefore, the third consensus call is warranted. We ask the working group to consider document publication in light of these recent changes:

- Promotion of Hybrids in draft-ietf-tls-ecdhe-mlkem: Following a separate consensus call, the WG agreed to promote the X25519MLKEM768 hybrid group to Recommended: Y in the IANA registry. Consequently, the IANA registry will reflect a clear community preference for a hybrid because Recommended: Y clearly indicates this while the standalone ML-KEM groups defined in this draft remain Recommended: N. The updated security considerations in [1] reference the IANA registry to emphasize this preference.

- Key Share Reuse Prohibited in draft-ietf-tls-rfc8446bis: The WG recently reached consensus to explicitly prohibit key share reuse across connections in TLS 1.3. The new text changes the guidance from SHOULD NOT to a strict MUST NOT. This resolves the concerns regarding static key reuse and its associated privacy and forward-secrecy risks for ML-KEM.

- Nadim updated the ProVerif model of TLS 1.3 to evaluate KEM and hybrid KEM groups in TLS 1.3. This supports other results which show that KEMs are secure when used in TLS 1.3 and that hybrid groups are secure even if one of the components is compromised.

- Liaisons: We received liaison statements from multiple SDOs including  O-RAN[2], IEEE 802.11[4] and from 3GPP[3]  expressing support for the publication of draft-ietf-tls-mlkem as an RFC as they rely on the IETF to provide a stable normative reference.

Please note that a third-party IPR disclosure exists [5] against this document regarding patents related to the underlying ML-KEM algorithm. This IPR declaration has not changed since the last WGLC. As a reminder, per BCP 79, the IETF takes no stance on the validity of patent claims, and the working group may decide to proceed with a technology despite IPR disclosures if it decides that such use is warranted.

Conduct Reminder: Given the heated nature of previous discussions on this topic, participants are strongly reminded to adhere to the IETF Code of Conduct (BCP 54) and the TLS WG's Mail List Procedures. Keep feedback professional, technical, and focused on the document's text.

This working group last call will end on 2026-07-08.

Joe and Sean

[1] https://datatracker.ietf.org/doc/draft-ietf-tls-mlkem/
[2] https://datatracker.ietf.org/liaison/2198/
[3] https://datatracker.ietf.org/liaison/2151/
[4] https://datatracker.ietf.org/liaison/2148/
[5] https://datatracker.ietf.org/ipr/search/?submit=draft&id=draft-ietf-tls-mlkem