I think the issue is that the id_token “audience” restrictions require them to 
be the same. Otherwise the “IdP Authorization Server” (that didn’t issue the 
id_token) would need to reject the id_token when received because the 
“audience” wouldn’t match. I’m not crazy about the idea that says a bunch of 
different services performing different tasks are still all the same “audience”.

George Fletcher
Identity Standards Architect
Practical Identity LLC



> On Nov 3, 2025, at 5:30 PM, Atul Tulshibagwale 
> <[email protected]> wrote:
> 
> Hi Jeff,
> I'm not thinking of changing anything in the draft (e.g. using Transaction 
> Tokens, WITs etc.)
> I'm only suggesting that we should not assume that the IdP that issued the 
> ID-Token is the same as the "IdP Authorization Server" that issues the ID-JAG.
> 
> Atul
> 
> 
> On Mon, Nov 3, 2025 at 1:29 PM Lombardo, Jeff 
> <[email protected] <mailto:[email protected]>> 
> wrote:
>> Not going against anything Aaron said, is your question @Atul Tulshibagwale 
>> <mailto:[email protected]> cause you are thinking ahead of:
>> 
>> 1/ A transaction Token could be exchanged for a ID-JAG?
>> 2/ A Workload Identity Token could be exchanged for an ID-JAG?
>> 
>>  
>> 
>> Jeff
>> 
>>  
>> 
>> Jean-François “Jeff” Lombardo | Amazon Web Services
>> 
>>  
>> 
>> Architecte Principal de Solutions, Spécialiste de Sécurité
>> Principal Solution Architect, Security Specialist
>> Montréal, Canada
>> 
>> 
>> Commentaires à propos de notre échange? Exprimez-vous ici 
>> <https://urldefense.com/v3/__https:/feedback.aws.amazon.com/?ea=jeffsec&fn=Jean*20Francois&ln=Lombardo__;JQ!!Pe07N362zA!0k9CkAV8Djpw_8EfIAKrbhP3TQrJr0oMnznlUgBJ3V3NoEk6hihx7dNHnQuejn6SSH2CP8Iow3G-tTzppHeg$>.
>> 
>>  
>> 
>> Thoughts on our interaction? Provide feedback here 
>> <https://urldefense.com/v3/__https:/feedback.aws.amazon.com/?ea=jeffsec&fn=Jean*20Francois&ln=Lombardo__;JQ!!Pe07N362zA!0k9CkAV8Djpw_8EfIAKrbhP3TQrJr0oMnznlUgBJ3V3NoEk6hihx7dNHnQuejn6SSH2CP8Iow3G-tTzppHeg$>.
>> 
>>  
>> 
>> From: Aaron Parecki <[email protected] 
>> <mailto:[email protected]>> 
>> Sent: November 3, 2025 4:17 PM
>> To: Atul Tulshibagwale <[email protected] 
>> <mailto:[email protected]>>
>> Cc: oauth <[email protected] <mailto:[email protected]>>
>> Subject: [EXT] [OAUTH-WG] Re: Separating the ID-JAG issuer from the ID-Token 
>> issuer
>> 
>>  
>> 
>> CAUTION: This email originated from outside of the organization. Do not 
>> click links or open attachments unless you can confirm the sender and know 
>> the content is safe.
>> 
>>  
>> 
>> AVERTISSEMENT: Ce courrier électronique provient d’un expéditeur externe. Ne 
>> cliquez sur aucun lien et n’ouvrez aucune pièce jointe si vous ne pouvez pas 
>> confirmer l’identité de l’expéditeur et si vous n’êtes pas certain que le 
>> contenu ne présente aucun risque.
>> 
>>  
>> 
>> For some background, the reason for this draft and the ID-JAG in the first 
>> place is to enable an Authorization Server to issue its own access tokens in 
>> response to a cross-domain artifact. This is better than the other two 
>> alternatives which would be:
>> 
>>  
>> 
>> 1. Client sends the IdP-issued ID Token to the Authorization Server in the 
>> other domain (violates ID Token "audience" policy processing)
>> 
>> 2. Have the IdP issue an access token that the Resource Server in the other 
>> domain accepts (no protocol violation, but experience has shown Resource 
>> Server implementers do not want this)
>> 
>>  
>> 
>> Now to your actual question, why not enable the ID-JAG issuer to be separate 
>> from the ID Token issuer. This would also violate the ID Token "audience" 
>> processing, since the ID Token would be presented to an entity different 
>> from the issuer of the ID Token.
>> 
>>  
>> 
>> On Mon, Nov 3, 2025 at 3:49 PM Atul Tulshibagwale 
>> <[email protected] <mailto:[email protected]>> wrote:
>> 
>> Hi all,
>> 
>> Great to see the "Identity Assertion JWT Authorization Grant 
>> <https://datatracker.ietf.org/doc/draft-ietf-oauth-identity-assertion-authz-grant/>"
>>  proposal being accepted by OAuth. I'd like to propose that we should not 
>> assume that the issuer of the ID-Token is the same as the issuer of the 
>> ID-JAG. There doesn't seem to be any reason provided for this either in the 
>> draft or in the short discussion we had today.
>> 
>>  
>> 
>> It's just something that is assumed in the draft, and I feel that can be 
>> generalized without affecting anything in the draft.
>> 
>>  
>> 
>> To address Aaron's response that "if you want them separate, then you return 
>> to the ID-Chaining draft": I feel there's a lot of value in this (ID-JAG) 
>> specification, and being able to apply to more use cases broadens the value 
>> of this specification.
>> 
>>  
>> 
>> I'd love to know what could be potential issues if the ID-JAG issuer is not 
>> assumed to be the same as the ID-Token issuer.
>> 
>>  
>> 
>> Thanks,
>> 
>> Atul
>> 
>>  
>> 
>> _______________________________________________
>> OAuth mailing list -- [email protected] <mailto:[email protected]>
>> To unsubscribe send an email to [email protected] 
>> <mailto:[email protected]>_______________________________________________
> OAuth mailing list -- [email protected]
> To unsubscribe send an email to [email protected]

_______________________________________________
OAuth mailing list -- [email protected]
To unsubscribe send an email to [email protected]

Reply via email to