Re: [COSE] [jose] Fwd: New Version Notification for draft-reddy-cose-jose-pqc-kem-00.txt

[Ilari Liusvaara <[e-mail]>]

On Wed, Mar 06, 2024 at 11:45:03AM +0530, tirumal reddy wrote:
> On Tue, 5 Mar 2024 at 20:12, AJITOMI Daisuke <[e-mail]> wrote:
> 
> > > I think we should use HPKE until there is reason not to use it.
> >
> > I agree.
> >
> > Regarding ML-KEM, I was thinking that we should add X-Wing as a PQ/T
> > Hybrid KEM to the list of COSE-HPKE ciphersuites at first.
> >
> > X-Wing: general-purpose hybrid post-quantum KEM
> > https://datatracker.ietf.org/doc/draft-connolly-cfrg-xwing-kem/
> >
> 
> X-wing is specific to hybrid schemes and it is back-ward compatible with
> X25519Kyber768Draft00. The COSE and JOSE HPKE specifications can use the
> above hybrid scheme which is already registered in HPKE IANA registry.

No, that does not work.

That KEM will never be published as an RFC, so the main COSE and JOSE
HPKE specifications can not reference it. And since all the HPKE
algorithms are fully specified, the main COSE and JOSE HPKE
specifications can not allow using it.

One would need a separate draft and use that as reference for the
needed algorithms.

X-Wing or whatever replaces it in HPKE (CFRG is just about to start the
project on hybrid KEMs) will be published as an RFC. However, that is
currently blocked on NIST publishing FIPS 203.




-Ilari