Re: [OAUTH-WG] Signed JWK Sets

I think Signed JWK sets are useful and would like to see them used in more
use cases so separating out the specifications seems like a good idea.  We
will have to be careful specify what security and deployment properties you
are trying to achieve in different use cases.

On Tue, Mar 19, 2024 at 11:36 AM Watson Ladd <watsonbladd@gmail.com> wrote:

> On Sun, Mar 17, 2024 at 5:32 PM Richard Barnes <rlb@ipv.sx> 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.
> >
>

[Joe] I think there may also be a consideration in some environments that
problems could arise if keys not intended for signing JWK sets could be
used to sign JWK sets.

> > 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.
>

[Joe] I think this can work and be useful in many cases, but there may be
some subtleties here that should be considered.  All the more reason to
document this.

> Sincerely,
> Watson
>
> --
> Astra mortemque praestare gradatim
>
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