Re: [OAUTH-WG] Fwd: New Version Notification for draft-richer-oauth-introspection-01.txt

Hi Justin,

Am 09.01.2013 um 20:35 schrieb Justin Richer <jricher@mitre.org>:

> Thanks for the review, answers inline:
>> why is there a need for both scope and audience? I would assume the scope of the authorization request is typically turned into an audience of an access token.
> 
> You can have an audience of a single server that has multiple scopes, or a single scope that's across multiple servers. Scope is an explicit construct in OAuth2, and while it is sometimes used for     audience restriction purposes, they really are independent. Note that both of these are optional in the response -- if the AS has no notion of audience restriction in its stored token metadata, then it just doesn't return the "audience" field.

You are making an interesting point here. To differentiate the resource server and the permissions of a particular at this server makes a lot of sense. BUT: the authorization request does not allow the client to specify both in separate parameters. Instead both must be folded into a single "scope" parameter. If I got your example correctly, the scope of the request would be

scope=myserver:read

whereas the results of the introspection would be

scope=read
audience=myserver

It's probably the different semantics of scope that confused me.

> 
>> 
>> Generally, wouldn't it be simpler (spec-wise) to just return a JWT instead of inventing another set of JSON elements?
> 
> What would be the utility in returning a JWT? The RS/client making the call isn't going to take these results and present them elsewhere, so I don't want to give the impression that it's a token. (This, incidentally, is one of the main problems I have with the Ping introspection approach, which uses the Token Endpoint and invents a "token type" as its return value.) Also, the resource server would have to parse the JWT instead of raw JSON, the latter of which is easier and far more common. Besides, I'd have to invent new claims for things like "valid" and "scopes" and what not, so I'd be extending JWT anyway. 
> 
> So while I think it's far preferable to use an actual JSON object, I'd be fine with re-using JWT claim names in the response if people prefer that. I tried to just use the expanded text since size constraints are not an issue outside of a JWT, so "issued_at" instead of "iat".
> 
> Finally, note that this is *not* the same as the old OIDC CheckId endpoint which merely parsed and unwrapped the data inside the token itself. This mechanism works just as well with an unstructured token as input since the AS can store all of the token's metadata, like expiration, separately and use the token's value as a lookup key.

I probably didn't describe well what I meant. I would suggest to return a JWT claim set from the introspection endpoint. That way one could use the same claims (e.g. iat instead of issued_at) for structured and handle-based tokens. So the logic operating on the token data could be the same.

regards,
Torsten.

> 
>  -- Justin
> 
>> Am 09.01.2013 um 20:10 schrieb Justin Richer <jricher@mitre.org>:
>> 
>>> Updated the introspection draft with feedback from the UMA WG, who have incorporated it into their latest revision of UMA. 
>>> 
>>> I would like this document to become a working group item.
>>> 
>>>  -- Justin
>>> 
>>> 
>>> -------- Original Message --------
>>> Subject:	New Version Notification for draft-richer-oauth-introspection-01.txt
>>> Date:	Tue, 8 Jan 2013 14:48:47 -0800
>>> From:	<internet-drafts@ietf.org>
>>> To:	<jricher@mitre.org>
>>> 
>>> A new version of I-D, draft-richer-oauth-introspection-01.txt
>>> has been successfully submitted by Justin Richer and posted to the
>>> IETF repository.
>>> 
>>> Filename:	 draft-richer-oauth-introspection
>>> Revision:	 01
>>> Title:		 OAuth Token Introspection
>>> Creation date:	 2013-01-08
>>> WG ID:		 Individual Submission
>>> Number of pages: 6
>>> URL:             http://www.ietf.org/internet-drafts/draft-richer-oauth-introspection-01.txt
>>> Status:          http://datatracker.ietf.org/doc/draft-richer-oauth-introspection
>>> Htmlized:        http://tools.ietf.org/html/draft-richer-oauth-introspection-01
>>> Diff:            http://www.ietf.org/rfcdiff?url2=draft-richer-oauth-introspection-01
>>> 
>>> Abstract:
>>>    This specification defines a method for a client or protected
>>>    resource to query an OAuth authorization server to determine meta-
>>>    information about an OAuth token.
>>> 
>>> 
>>>                                                                                   
>>> 
>>> 
>>> The IETF Secretariat
>>> 
>>> 
>>> 
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>>> OAuth mailing list
>>> OAuth@ietf.org
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> 