I think your point that maybe the architecture doc be generic enough to support both json and cbor tokens is worth consideration.
I am just not sure of process and consensus now that we are past WGLC. Would the cose group prefer this? Happy to do it if desired. Also understand if we are too far down the road. Phil > On Nov 19, 2015, at 08:39, Erik Wahlström neXus > <[email protected]> wrote: > > Just a note then. I did not see anything that prohibited the usage of pop > tokens for IoT so shipping it as is works. > > Sent from my iPhone > > On 19 Nov 2015, at 17:18, Phil Hunt <[email protected]> wrote: > >> On the subject of making the spec(s) less JWT specific, it was a >> foundational assumption and (I think) in the charter. However COSE wasn't >> around yet. >> >> I suppose the more generic architecture doc could be altered to cover IoT >> cases, but it may be problematic for the other specs that are more specific. >> >> Another issue is I assume the COSE based tokens will have a different type >> (eg cpop) to differentiate between jwt and COSE web tokens (what are we >> calling them now?). >> >> As this generalization change could be seen as substantial, I would like to >> have the chairs and AD comment. Is this a good idea? Or is COSE better to >> write their own parallel arch draft? >> >> I'm happy to bend to the will of the group(s) on this. >> >> Phil >> >> On Nov 19, 2015, at 01:17, Erik Wahlström neXus >> <[email protected]> wrote: >> >>> Hi, >>> >>> I have been reviewing draft-ietf-oauth-pop-architecture-05. In ACE WG we >>> have a draft that uses PoP tokens for IoT and the architectures defined >>> here so my review was done with that IoT perspective. I’m a bit late with >>> the review and some of the comments might already be mentioned by others. >>> >>> >>> >>> —————— >>> >>> 3.1. Preventing Access Token Re-Use by the Resource Server >>> >>> If a symmetric key is used it’s possible to re-use the key for a resource >>> server. The section talks about the importance of scopes, but I feel it >>> should also mention the importance for the resource server to verify the >>> audience (“aud”) claim in the token to disable missuse. >>> >>> —————— >>> >>> The draft in ACE WG >>> (https://tools.ietf.org/html/draft-seitz-ace-oauth-authz-00) relies heavily >>> on this work. The main reason for this is the way PoP tokens can establish >>> key material, with the help of the authorization server, on both the client >>> and resource server. PoP tokens is also a very good fit for constrained IoT >>> devices that can be offline and it’s also possible to use hardware key >>> storages to handle asymmetric pop keys. >>> >>> There could be a place for a new "Use Case" under section 3 that talks >>> about scenarios where PoP keys are a really good match for offline IoT >>> devices. I could help out ironing out a text for that with the help of the >>> docs authors if that’s of interest. >>> >>> ——— >>> >>> s/a bogus tokens/a bogus token >>> >>> —— >>> >>> In the document only references are made to JSON, JWT and JOSE. More >>> exactly in the following two sections: >>> >>> A number of the threats listed in Section 4 demand protection of the >>> access token content and a standardized solution, in form of a JSON- >>> based format, is available with the JWT [RFC7519]. >>> >>> >>> With the JSON Web Token (JWT) [RFC7519] a standardized format for >>> access tokens is available. The necessary elements to bind symmetric >>> or asymmetric keys to a JWT are described in >>> [I-D.ietf-oauth-proof-of-possession]. >>> >>> Constrained IoT devices uses other access token and messages formats >>> (according to our draft). It does not only use signed/encrypted JWT’s but >>> also COSE protected CBOR Web Tokens. See >>> https://tools.ietf.org/id/draft-wahlstroem-oauth-cbor-web-token-00.txt >>> >>> I totally agree that JWT is the correct examples to have in this document >>> due to the fact that they are RFC’s, they are well known and should be used >>> in as many places as possible, but it would be good to open up for other >>> types of message formats. For example like this: >>> >>> >>> A number of the threats listed in Section 4 demand protection of the >>> access token content and a standardized solution in form of, for >>> example, a JSON- >>> based format, is available with the JWT [RFC7519]. >>> >>> >>> —— >>> >>> For that >>> purpose the client will have to authenticate the resource server >>> before transmitting the access token. >>> >>> >>> I’m missing a description about how this is handled in an end-to-end >>> security scenario. >>> >>> ——— >>> >>> The resource server queries the authorization server for the >>> symmetric key. This is an approach envisioned by the token >>> introspection endpoint [I-D.ietf-oauth-introspection]. >>> >>> >>> Not a question for this draft maybe, but in what draft is the introspection >>> response claim defined? It’s not defined in >>> https://tools.ietf.org/html/rfc7662#section-2.2 and I don’t know in what >>> other draft it can be defined. >>> >>> —— >>> >>> In ACE WG the draft seitz-ace-oauth-authz have a profile for an access >>> request to make it work over CoAP. CoAP is the HTTP equivalent for >>> constrained devices, and it has limitations, for example it can’t send >>> large tokens in options (headers in "http-speak"). This means that the >>> draft defines a way to first send the PoP token to an new endpoint on the >>> resource server to establish a security context. Then the real request >>> against the resource server can be done once the security context is >>> established. See more details here >>> https://tools.ietf.org/html/draft-seitz-ace-oauth-authz-00#section-5.2. >>> >>> An open question; should a flow like that be added to the architecture >>> section? That means a new section 7.5. >>> >>> —— >>> >>> Thanks for writing this. I think it’s very important work. >>> >>> / Erik >>> _______________________________________________ >>> OAuth mailing list >>> [email protected] >>> https://www.ietf.org/mailman/listinfo/oauth
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