Re: [OAUTH-WG] Signed JWK Sets

[Watson Ladd <[e-mail]>]

On Sun, Mar 17, 2024 at 5:32 PM Richard Barnes <[e-mail]> wrote:
>
> Hi Watson,
>
> I appreciate the concerns with regard to re-using Web PKI certs for cases such as these.  Care is required, but I think there is a path here.
>
> 1. Clearly there are cross-protocol concerns.  I expect that most usage here in reality would be based on ECDSA / EdDSA, not RSA, which helps.  I would be comfortable with security considerations recommending that a key pair / certificate used for signing these things be used for no other purpose.
>
> 2. Validity times are definitely a challenge for the container signing use case, but from the conversations I've had with that community, they are taking an orthogonal approach.  As I tried to sketch in the document, they are establishing authorities that will vouch that a signed thing existed at a given time, so that a relying party can safely rewind their clock and validate as if it were that time.  See, e.g., SigStore <https://www.sigstore.dev/>, which has roughly this shape if you squint right.

That should work out: might want a security considerations saying this.

>
> 3. I don't think there's actually any disconnect between HTTPS authentication and proof of authority.  The Web PKI is about authenticating domain names, which is what both use cases require.

Only with certain validation methods. Others like agreed upon change
to site content have a narrower scope and the BRs reflect this
subtlety. To be honest you're probably safe and I am not the expert
here.

Sincerely,
Watson

--
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