Re: [OAUTH-WG] ECDH-1PU encryption algorithm

Hi Neil,

I'm interested in seeing both AES SIV and ECDH-1PU for JOSE. Not sure how
to go about it tho since JOSE is a concluded WG.

Out of curiosity, why is it a concluded WG? Did IETF/JOSE WG not consider
the need to further maintain/expand the JOSE algorithms as time goes on?

S pozdravem,
*Filip Skokan*

On Mon, 10 Aug 2020 at 10:29, Neil Madden <neil.madden@forgerock.com> wrote:

> Thanks Vladimir,
>
> Responses below
>
> > On 8 Aug 2020, at 10:40, Vladimir Dzhuvinov <vladimir@connect2id.com>
> wrote:
> >
> > Hi Neil,
> >
> > I definitely like the elegance of the proposed alg for JOSE, it provides
> > something that isn't currently available in the various classes of algs
> > made standard in JOSE.
> >
> > I also wanted to ask what's happening with AES SIV for JOSE, if there's
> > traction / feedback / support there as well?
> >
> > https://tools.ietf.org/html/draft-madden-jose-siv-mode-02
>
> Thanks for bringing this up. I’ve not received much feedback about this
> one, and I haven’t been very good at pushing it. If there is interest then
> I’d certainly be interested in bringing this forward too.
>
> That draft might be a better fit for eg the COSE WG though, which could
> then also register identifiers for JOSE. What do you think?
>
> >
> > Vladimir
> >
> >
> >>> On 05/08/2020 13:01, Neil Madden wrote:
> >> Hi all,
> >> You may remember me from such I-Ds
> >> as https://tools.ietf.org/html/draft-madden-jose-ecdh-1pu-03, which
> >> proposes adding a new encryption algorithm to JOSE. I’d like to
> >> reserve a bit of time to discuss it at one of the upcoming interim
> >> meetings.
> >> The basic idea is that in many cases in OAuth and OIDC you want to
> >> ensure both confidentiality and authenticity of some token - for
> >> example when transferring an ID token containing PII to the client
> >> through the front channel, or for access tokens intended to be handled
> >> by a specific RS without online token introspection (such as the JWT
> >> access token draft). If you have a shared secret key between the AS
> >> and the client/RS then you can use symmetric authenticated encryption
> >> (alg=dir or alg=A128KW etc). But if you need to use public key
> >> cryptography then currently you are limited to a nested
> >> signed-then-encrypted JOSE structure, which produces much larger token
> >> sizes.
> >> The draft adds a new “public key authenticated encryption” mode based
> >> on ECDH in the NIST standard “one-pass unified” model. The primary
> >> advantage for OAuth usage is that the tokens produced are more compact
> >> compared to signing+encryption (~30% smaller for typical access/ID
> >> token sizes in compact serialization). Performance-wise, it’s roughly
> >> equivalent. I know that size concerns are often a limiting factor in
> >> choosing whether to encrypt tokens, so this should help.
> >> In terms of implementation, it’s essentially just a few extra lines of
> >> code compared to an ECDH-ES implementation. (Some JOSE library APIs
> >> might need an adjustment to accommodate the extra private key needed
> >> for encryption/public key for decryption).
> >> I’ve received a few emails off-list from people interested in using it
> >> for non-OAuth use-cases such as secure messaging applications. I think
> >> these use-cases can be accommodated without significant changes, so I
> >> think the OAuth WG would be a good venue for advancing this.
> >> I’d be interested to hear thoughts and discussion on the list prior to
> >> any discussion at an interim meeting.
> >> — Neil
>
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