Hi all,

Bit late to the party, but I was asked to comment from the perspective 
of the draft for PQC in Web Crypto [1].

FWIW, I think this is the right outcome, and it will simplify the use of 
JWK in Web Crypto (and in general) by only specifying a single key 
format. The current draft also only specifies a seed format for 
importing/exporting private keys, and this will make it consistent once 
JWK is added.

(The alternative might've been to only allow the JWK format with a seed, 
as I'm contemplating to do for PKCS8.)

Thanks!

Best,
Daniel

[1]: https://twiss.github.io/webcrypto-modern-algos/pqc.html


On 21-05-2025 at 07:10, Michael Jones wrote:
>
> Ivo and I discussed the results from the query “Do COSE and JOSE need 
> both "priv" and "seed"?” sent to the COSE and JOSE mailing lists and 
> have made the following consensus call together, so as to unblock 
> progress on completing the draft.  While there wasn’t an easy answer, 
> we believe that our decision appropriately balances considerations of 
> simplicity, practicality, and interoperability.
>
> Authors of draft-ietf-cose-dilithium,
>
> Please apply these revisions and publish the result as draft 07.
>
>   * Restore the meaning of “priv” to always be the seed value.
>   * Delete the “seed” AKP parameter.
>   * State that this specification intentionally does not define a
>     means of utilizing the expanded private key representation defined
>     by NIST so as to increase interoperability by having a single
>     ML-DSA private key representation for COSE and JOSE.
>
> I’ll note that much of this can be accomplished by restoring text from 
> draft 05.
>
> Following publication of 07 with these changes, the chairs will 
> request publication of the specification.
>
> The working group is aware of the LAMPS WG decision to specify both 
> seed and expanded representations, but that reason was mostly related 
> by the existence of hardware HSMs that only support the expanded 
> format.  We do not anticipate that the same problem will exist for 
> COSE or JOSE.
>
> Proponents of having multiple private key representations,
>
> If any of you feel strongly enough about wanting to also have the 
> expanded key representation be possible for COSE and JOSE, we would 
> request that you create a separate draft doing so. Such a draft would 
> be expected to define an optional “expanded” parameter to the AKP key 
> type.  It would include the rule that if both “priv” and “expanded” 
> are present, they must represent the same private key, just as “seed” 
> and “priv” must correspond in draft 06.  The chairs are not taking a 
> position in this consensus call on whether such a draft should be 
> created or not.
>
> Writing as COSE chairs,
>
> -- Ivo and Mike
>

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