Mike et al,

Overall, this document has some really great advice for people who have chosen 
to use JWT in various situations. It’s a needed draft and I’d like to see it go 
forward. I have some suggestions on how it can be improved.

In this draft, I’d like to see some more discussion about privacy and security 
issues around choosing JWTs to begin with. Namely, putting things like subject 
identifiers and scope/permission information into the JWT structure could 
potentially leak information about the end user to the client, if the JWT isn’t 
encrypted, and to multiple RS’s, if the JWT is encrypted with a shared key. It 
basically amounts to “anyone who can read the JWT can see what’s in it”, which 
on the one hand is obvious, but on the other hand it’s not always considered by 
implementers. Since the audience of an access token JWT is the RS and not the 
client, and the token is opaque to the client, it’s easy to assume that the 
client *won’t* read the token. However, that doesn’t mean that it *can’t* read 
the token. It’s a tradeoff in design space with other solutions.

I’d also like to see a discussion on expiration and revocation of 
self-contained JWT access tokens. Again, this is targeting the decision space 
of whether or not a self-contained token is an appropriate solution in the 
first place. If I’m issuing JWTs that are completely self-contained, I can’t 
revoke them once they’re on the wire. Yes, that’s an acceptable risk to many 
and that’s fine — but I would like this document to encourage that thought and 
discussion. 

Thanks,
 — Justin

> On Jul 4, 2017, at 3:43 PM, Mike Jones <michael.jo...@microsoft.com> wrote:
> 
> The JWT BCP draft has been updated to describe the use of explicit typing of 
> JWTs as one of the ways to prevent confusion among different kinds of JWTs.  
> This is accomplished by including an explicit type for the JWT in the “typ” 
> header parameter.  For instance, the Security Event Token (SET) specification 
> <http://self-issued.info/?p=1709> now uses the “application/secevent+jwt” 
> content type to explicitly type SETs.
>  
> The specification is available at:
> https://tools.ietf.org/html/draft-sheffer-oauth-jwt-bcp-01 
> <https://tools.ietf.org/html/draft-sheffer-oauth-jwt-bcp-01>
>  
> An HTML-formatted version is also available at:
> http://self-issued.info/docs/draft-sheffer-oauth-jwt-bcp-01.html 
> <http://self-issued.info/docs/draft-sheffer-oauth-jwt-bcp-01.html>
>  
>                                                        -- Mike
>  
> P.S.  This notice was also posted at http://self-issued.info/?p=1714 
> <http://self-issued.info/?p=1714> and as @selfissued 
> <https://twitter.com/selfissued>.
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