Hi Ilari,
Given ML-KEM-512 = TBD1 in the COSE Algorithms Registry my understanding is
that the COSE_KEY part of a CWT would be:
1 : { /COSE_Key/
1 : 7, / kty /
3 : <TBD1> / alg /
2 : h'00', / kid /
-2 : h'<ML-KEM-512 public key>' / x /
}
I think this would work for EDHOC. Seems very similar to a CWT for X25519
1 : { /COSE_Key/
1 : 1, / kty /
2 : h'00', / kid /
-1 : 4, / crv /
-3 : h’<X25519 public key>' / x /
}
A static key in a CWT would be used for authentication.
>For draft-spm-lake-pqsuites, seems like it only needs signature keys,
>which AKP was designed for (why is draft-ietf-jose-pqc-kem a normative
>reference? It does not seem to be used for anything...)
draft-spm-lake-pqsuites uses the code point in the COSE algorithms registry.
draft-spm-lake-pqsuites use ephemeral ML-KEM for key exchange together with
PSK, Signature, or Static DH authentication. KEM authentication may be
specified later.
(If would be a bit strange to use the same alg for key exchange and
authentication, but I don’t think it would cause any problems for EDHOC).
Cheers,
John
From: Ilari Liusvaara <[email protected]>
Date: Saturday, 7 March 2026 at 16:13
To: JOSE WG <[email protected]>, cose <[email protected]>
Subject: [jose] Re: [COSE] Re: Re: COSE and LAKE needs draft-ietf-jose-pqc-ke
(was Proposal: Use HPKE for JWE PQ/PQT straight away)
On Sat, Mar 07, 2026 at 08:25:03AM -0600, Orie wrote:
> On Sat, Mar 7, 2026, 2:31 AM John Mattsson <john.mattsson=
> [email protected]> wrote:
>
> Hi,
>
> I'm not very familiar with edhoc, but if edhoc supports multiple
> algorithms, and has private and public key components, AKP could be used.
>
> If edhoc needs kems without hpke, new COSE algorithms would be need to be
> registered.
>
> { kty: AKP, alg: <kem>, pub:..., priv:..}
>
> If edhoc, needs a key representation that does not commit to a specific kem
> algorithm, then AKP is not a suitable option.
>From the quoted post by John Mattsson: "In the future, LAKE would likely
want to use CWTs with public KEM keys for authentication.".
Those keys do not commit to any KEM algorithm (at least one that makes
any sense in COSE).
For draft-spm-lake-pqsuites, seems like it only needs signature keys,
which AKP was designed for (why is draft-ietf-jose-pqc-kem a normative
reference? It does not seem to be used for anything...)
-Ilari
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