> On the specific question of encoding the encapsulated keys -- It would be
a mistake to encode these as keys.
Agree. As I stated in [2][3], I am strongly opposed to encoding
encapsulated keys into COSE_Key (or JWK).
I am talking about the recipient public key. The following example is just
one approach. I believe there are multiple approaches.
```
keys: [
{
"kty": "HPKE",
"kid": "x25519-01",
"kem": 0x0020, // DHKEM(X25519, HKDF-SHA256)
"kdfs": [0x0001, 0x0002, 0x0003], // All of the currently defined
KDFs are acceptable.
"aeads": [0x0001, 0x0002, 0x0003], // All of the currently defined
AEADs are acceptable.
"pub": "2E6dX83gqD_D0eAmqnaHe1TC1xuld6iAKXfw2OVATr0", //
base64-encoded X25519 public key.
}
]
```
Regards,
Daisuke
2022年9月22日(木) 22:01 Richard Barnes <[email protected]>:
> On the specific question of encoding the encapsulated keys -- It would be
> a mistake to encode these as keys. The HPKE spec deliberately treats these
> as opaque byte strings to preserve agility with regard to the KEM. In
> DHKEM, the encapsulated value is a serialized public key, but that is not
> true more generally.
>
> --RLB
>
> On Thu, Sep 22, 2022 at 8:34 AM AJITOMI Daisuke <[email protected]> wrote:
>
>> Hi folks,
>>
>> I've heard that the JOSE WG is considered to be restarted.
>>
>> Currently, during some discussions on "Use of HPKE with COSE''[1] in the
>> COSE WG, the topic of how to represent HPKE public keys has been
>> raised[2][3]. Specifically, it concerns whether encapsulated keys
>> (ephemeral **sender** public keys) for HPKE should be represented by
>> COSE_Key (binary version of JWK) or not and I am of the opinion that it is
>> not necessary to express them in COSE_Key.
>>
>> On the other hand, however, I'm thinking it would be better to have a
>> standardized way and format for publishing **recipient** public keys for
>> HPKE. In particular, I believe that if we can express them in very popular
>> JWK format and publish them via developer-friendly jwks_uri endpoints the
>> use of HPKE on the application layer will be facilitated.
>>
>> Would this topic be inside the scope of the new JOSE WG planned to be
>> re-chartered?
>>
>> I would like to hear from the experts on this mailing list.
>>
>> Best regards,
>> Ajitomi, Daisuke
>>
>> [1] https://www.ietf.org/archive/id/draft-ietf-cose-hpke-02.html
>> [2]
>> https://mailarchive.ietf.org/arch/msg/cose/kI10B-xaIUFTeN2lZNXKsgYBMSs
>> [3]
>> https://mailarchive.ietf.org/arch/msg/cose/Rg_AAtgOL4p9SdlXHyL8-0HSrI8
>> _______________________________________________
>> jose mailing list
>> [email protected]
>> https://www.ietf.org/mailman/listinfo/jose
>>
>
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