Hi Kai, I see your point. I agree that the subject_token may not need to be signed depending on the deployment. This was true when we made the proposal that the subject_token could be a simple string (e.g. email address). If the subject_token is signed, the TTS could verify that the subject_token was issued by the same client making the request. However, that might not always be valid either:)
Thanks, George On Tue, Apr 23, 2024 at 11:25 AM Kai Lehmann <kai.lehmann= 401und1...@dmarc.ietf.org> wrote: > Hi George, > > > > The Token Exchange request ist requiring client authentication. A TTS > needs to trust this authenticated client to provide a correct subject to > some extend. This is also the case if the client would provide a > self-signed JWT containing the subject instead. Using a JWT as a subject > token has definitely some benefits as the format/content can be specified, > but I don’t see how signing the JWT would make the trust by the TTS towards > the client unnecessary. > > > > Best regards, > > Kai > > > > *From: *OAuth <oauth-boun...@ietf.org> on behalf of George Fletcher > <george.fletcher=40capitalone....@dmarc.ietf.org> > *Date: *Monday, 22. April 2024 at 17:50 > *To: *Kai Lehmann <kai.lehmann=401und1...@dmarc.ietf.org> > *Cc: *oauth <oauth@ietf.org> > *Subject: *Re: [OAUTH-WG] [External Sender] Re: Transaction Tokens > issuance in the absence of incoming token > > > > Kai, > > > > How would the TTS trust the incoming "subject" value if not signed? Do you > have something in mind? > > > > Thanks, > > George > > > > On Tue, Apr 16, 2024 at 3:46 AM Kai Lehmann <kai.lehmann= > 401und1...@dmarc.ietf.org> wrote: > > Hi, > > > > Sorry for replying to this so late to this thread. Although self-signed > JWTs may help to fill the subject_token for Token Exchange, I think it can > be a burden for the Workload presenting the Self signed JWT as well as for > the Txn Token Service to validate that token. It would require the Workload > to do generate and maintain proper signing key material – including > rotating those keys on a regular basis as well as making them available to > the Txn Token Service. Workloads may not have the capability to serve a > JKWS file as they are purely operating in a backend environment (batch > processes). > > > > As this discussion is more or less already concluded, I hope that the spec > can at least allow alternatives. > > > > BR, > > Kai > > > > > > *From: *George Fletcher <george.fletcher=40capitalone....@dmarc.ietf.org> > *Date: *Friday, 12. April 2024 at 19:53 > *To: *Atul Tulshibagwale <a...@sgnl.ai> > *Cc: *Brian Campbell <bcampb...@pingidentity.com>, Kai Lehmann < > kai.lehm...@1und1.de>, Dmitry Telegin <dmit...@backbase.com>, oauth < > oauth@ietf.org> > *Subject: *Re: [External Sender] Re: [OAUTH-WG] Transaction Tokens > issuance in the absence of incoming token > > > > Atul has submitted this PR to address this issue. > > https://github.com/oauth-wg/oauth-transaction-tokens/pull/90 > <https://urldefense.com/v3/__https:/github.com/oauth-wg/oauth-transaction-tokens/pull/90__;!!FrPt2g6CO4Wadw!MJMc1NL3i2PsNlotzn7SBEzXnweUxiyc1sBVhxviBFDM_zf5l4muEFfQglVXdrP1XyOx-6BD_ilSfJBKaSgbcUATv14buN0ZfpAxA9o$> > > > > On Fri, Apr 12, 2024 at 12:10 PM Atul Tulshibagwale <a...@sgnl.ai> wrote: > > Thanks all, for your input. We discussed alternatives on a call last week > <https://urldefense.com/v3/__https:/hackmd.io/@rpc-sec-wg/BkdOgipkA__;!!FrPt2g6CO4Wadw!IaritBR30A-OIqtvw3r5q6_aqkOROPghBPV4SoaRKASDbORVwY8WPRHKgkC7kPF3SIu2uOfYw3rthSUvjiHD$>, > and arrived at using self-signed tokens with token exchange as a way > forward. > > > > On Fri, Apr 5, 2024 at 10:58 AM Brian Campbell <bcampb...@pingidentity.com> > wrote: > > One potential benefit of keeping the use of Token Exchange is that some AS > products/implementations have built a fair amount of configurability and > extensibility into their Token Exchange support, which might allow for > existing systems to be set up to do Transaction Tokens. Whereas a new > endpoint or new grant type are more likely to require code changes to the > core AS. Obviously this isn't universally true but something to consider > nonetheless. > > > > On Fri, Apr 5, 2024 at 4:13 AM Kai Lehmann <kai.lehmann= > 401und1...@dmarc.ietf.org> wrote: > > Hi, > > > > that is my thought as well. It does not necessarily be a Token Exchange > profile, but the Token endpoint makes sense as Tokens are issued. Defining > a specific Token grant with the necessary input parameters would fit nicely. > > > > Best regards, > > Kai > > > > *From: *OAuth <oauth-boun...@ietf.org> on behalf of Dmitry Telegin > <dmitryt=40backbase....@dmarc.ietf.org> > *Date: *Friday, 5. April 2024 at 00:41 > *To: *Atul Tulshibagwale <a...@sgnl.ai> > *Cc: *oauth <oauth@ietf.org> > *Subject: *Re: [OAUTH-WG] Transaction Tokens issuance in the absence of > incoming token > > > > Hello Atul, > > > > As an alternative to Token Exchange and separate (new) endpoint, have you > ever considered OAuth 2.0 Extension Grants > <https://urldefense.com/v3/__https:/datatracker.ietf.org/doc/html/rfc6749*section-4.5__;Iw!!FrPt2g6CO4Wadw!IaritBR30A-OIqtvw3r5q6_aqkOROPghBPV4SoaRKASDbORVwY8WPRHKgkC7kPF3SIu2uOfYw3rthaF41vnj$>? > This could give us more flexibility as will let us define our own set of > input parameters and validation rules (opposite to Token Exchange that > restricts us to subject_token and friends). > > > > Regards, > > Dmitry > > > > On Thu, Apr 4, 2024 at 11:02 PM Atul Tulshibagwale <a...@sgnl.ai> wrote: > > Thanks very much for your feedback, Joe! > > > > On Wed, Apr 3, 2024 at 10:16 AM Joseph Salowey <j...@salowey.net> wrote: > > Hi Atul, > > > > I'm just starting to review the transaction tokens draft and have only a > minimal understanding of the token exchange document at this point so I'm > lacking a little background, but I have a few comments and questions below. > > > > On Fri, Mar 29, 2024 at 10:39 AM Atul Tulshibagwale <a...@sgnl.ai> wrote: > > Hi all, > > We had a meeting today (notes here > <https://urldefense.com/v3/__https:/hackmd.io/@rpc-sec-wg/HJNXYKkk0__;!!FrPt2g6CO4Wadw!IaritBR30A-OIqtvw3r5q6_aqkOROPghBPV4SoaRKASDbORVwY8WPRHKgkC7kPF3SIu2uOfYw3rthSyWxSbV$>) > in which we discussed the question of what we should do if there is no > incoming (external) token in the request to issue a Transaction Token > <https://urldefense.com/v3/__https:/datatracker.ietf.org/doc/draft-ietf-oauth-transaction-tokens/__;!!FrPt2g6CO4Wadw!IaritBR30A-OIqtvw3r5q6_aqkOROPghBPV4SoaRKASDbORVwY8WPRHKgkC7kPF3SIu2uOfYw3rthe6t5FmT$> > (TraT). We identified a few circumstances under which this can happen: > > - The requesting service is triggered by a non-OAuth based flow such > as email or an internal trigger > - The client of the requesting service uses means other than an access > token to authorize the call (e.g. MTLS) > > [Joe] I think there will be a fair number of systems that support means of > authorizing non-oauth flows. > > > > > > We identified a few possibilities listed below. Please note that the > Transaction Tokens draft assumes that the TraT Service trusts the > requesting service, so all the possibilities below assume this. > > > > > > [Joe] yes, you are trusting another part of the system to perform some > authorization and inform the token service of the result. > > > > Here are some possibilities we discussed: > > 1. *Request Details*: Put the subject information in the > request_details parameter of the TraT request, and the subject_token value > is set to "N_A" > 2. *Self-Signed Token*: The requester generates a self-signed JWT that > has the subject information and puts that in the subject_token value > > [Joe] I like having signed tokens, but if this is really information just > exchanged between two endpoints it may be more work than necessary. > > > 1. *Separate Separate Endpoint*: The TraT service exposes a separate > endpoint to issue TraTs when there is no incoming token, and that endpoint > can be defined such that the request does not have a subject_token > parameter. This endpoint is not a profile of OAuth Token Exchange > 2. *Separate Endpoint Only*: Extending the thought above, the > requester can always extract the content of the incoming token into the > "request_details" parameter, so why do we need the Token Exchange endpoint > > [Joe] What do we gain by using token exchange? While it seems that there > is overlap between delegation/impersonation it seems that transaction > tokens are sort of a superset and contain additional information about the > context of the transaction. If it looks like token exchange is too > constraining then transaction tokens may just be a different use case. > With the understanding I currently have I'd either go with 4. Separate > Endpoint Only or 2. Self Signed token. Splitting the endpoints could be > valid, but it seems a bit weird for me, if we did decide to do that then > probably we wouldn't need to sign the information unless the request is > going to traverse multiple systems. > > > > > > We would like to understand how the group feels about these choices, or if > you have other suggestions / thoughts on this topic. > > > > Thanks, > > Atul > > > > -- > > *Error! Filename not specified.* > <https://urldefense.com/v3/__https:/sgnl.ai/__;!!FrPt2g6CO4Wadw!IaritBR30A-OIqtvw3r5q6_aqkOROPghBPV4SoaRKASDbORVwY8WPRHKgkC7kPF3SIu2uOfYw3rthWE6M_vP$> > > Atul Tulshibagwale > > CTO > > *Error! Filename not specified.* > <https://urldefense.com/v3/__https:/linkedin.com/in/tulshi__;!!FrPt2g6CO4Wadw!IaritBR30A-OIqtvw3r5q6_aqkOROPghBPV4SoaRKASDbORVwY8WPRHKgkC7kPF3SIu2uOfYw3rthdcL8-tf$>*Error! > Filename not specified.* > <https://urldefense.com/v3/__https:/twitter.com/zirotrust__;!!FrPt2g6CO4Wadw!IaritBR30A-OIqtvw3r5q6_aqkOROPghBPV4SoaRKASDbORVwY8WPRHKgkC7kPF3SIu2uOfYw3rthbfiKcf_$>*Error! > Filename not specified.* <a...@sgnl.ai> > > _______________________________________________ > OAuth mailing list > OAuth@ietf.org > https://www.ietf.org/mailman/listinfo/oauth > <https://urldefense.com/v3/__https:/www.ietf.org/mailman/listinfo/oauth__;!!FrPt2g6CO4Wadw!IaritBR30A-OIqtvw3r5q6_aqkOROPghBPV4SoaRKASDbORVwY8WPRHKgkC7kPF3SIu2uOfYw3rthVWkx-Kq$> > > _______________________________________________ > OAuth mailing list > OAuth@ietf.org > https://www.ietf.org/mailman/listinfo/oauth > <https://urldefense.com/v3/__https:/www.ietf.org/mailman/listinfo/oauth__;!!FrPt2g6CO4Wadw!IaritBR30A-OIqtvw3r5q6_aqkOROPghBPV4SoaRKASDbORVwY8WPRHKgkC7kPF3SIu2uOfYw3rthVWkx-Kq$> > > _______________________________________________ > OAuth mailing list > OAuth@ietf.org > https://www.ietf.org/mailman/listinfo/oauth > <https://urldefense.com/v3/__https:/www.ietf.org/mailman/listinfo/oauth__;!!FrPt2g6CO4Wadw!IaritBR30A-OIqtvw3r5q6_aqkOROPghBPV4SoaRKASDbORVwY8WPRHKgkC7kPF3SIu2uOfYw3rthVWkx-Kq$> > > > *CONFIDENTIALITY NOTICE: This email may contain confidential and > privileged material for the sole use of the intended recipient(s). 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