On Sun, Apr 23, 2023 at 12:59:08PM -0700, Laurence Lundblade wrote:
> On Apr 22, 2023, at 12:54 AM, Ilari Liusvaara <[email protected]> 
> wrote:
> > 
> > On Fri, Apr 21, 2023 at 06:15:31PM -0700, Laurence Lundblade wrote:
> >> A couple of observations:
> >> 
> >> HPKE isn’t an algorithm like RSA or the PQ algorithms or EC. It’s a
> >> user of those algs (except RSA). We’re not defining new a key type the
> >> way RFC 8230, RFC 8812 and RFC 9053 do. We already have the key types
> >> to work with HPKE KEMs. Seems like the sole thing is to define how
> >> alg restriction with the alg parameter works for HPKE.
> > 
> > I do not think this is correct. 
> > 
> > - We do not have key tpyes to work with HPKE KEMs. All the current ones
> >  yes, but that is one expert review away from changing. In contrast,
> >  the HPKE kty truly offers key type for all HPKE KEMs.
> 
> These are just key serialization formats. I don’t see why an expert
> would disallow them or what the basis of that prohibition would be.
> The threat that an expert will revoke use of key type with HPKE is
> probably not a good strategy to win people over to HPKE. It makes me
> look at the lack of policy and criteria for the HPKE IANA algorithm
> registry with worry. It would also be hard to enforce any sort of
> global prohibition.

I did not mean any prohibition or any sort of revocation.

I meant, e.g., draft-cfrg-schwabe-kyber-01 getting approved in expert
review. Afterwards, the present kty's are no longer sufficient.


> I don’t want a new kty for HPKE.
> - A new key type would bring the need for conversion to/from

The new key type would directly encode values to/from HPKE, making
the conversion trivial.

All the other kty's require nontrivial conversion.
- OKP needs remapping the crv value.
- EC2 needs highly nontrivial conversion, including point
  decompression.




-Ilari

_______________________________________________
COSE mailing list
[email protected]
https://www.ietf.org/mailman/listinfo/cose

Reply via email to