Re: [OAUTH-WG] New Version Notification for draft-ietf-oauth-dpop-01.txt

Brian Campbell <> Fri, 06 November 2020 22:02 UTC

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From: Brian Campbell <>
Date: Fri, 6 Nov 2020 15:02:07 -0700
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To: Neil Madden <>
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Subject: Re: [OAUTH-WG] New Version Notification for draft-ietf-oauth-dpop-01.txt
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On Tue, May 5, 2020 at 2:52 PM Brian Campbell <>

>> 9.1:
>> This would be a good place to mention BREACH as an example of how a DPoP
>> proof (and AT) might leak, despite only being sent over a direct HTTPS
>> channel. Note though that adding a random jti is an effective defence
>> against this even if the server doesn’t check it.
> Thanks for that note as a good reason to keep jti even if the requirements
> on checking it are relaxed.

In trying to add some text that makes such mention I realized (again) that
I don't have a very good understanding of BREACH. With a bit of reading of
the overview and paper at it seems that BREACH is
applicable to attacking compression for leaking sensitive information in
HTTP responses. Whereas a DPoP proof is only defined to be sent in an HTTP
request. And ATs are only in a response once and then used in requests.
Perhaps it's a limitation of my own imagination or intellect but I don't
see how BREACH is relevant here. If you can explain it to me "for dummies"
style or better yet propose some text, we can certainly look at adding it.
Short of that though, I'm not equipped to write anything legitimate about
it and will just omit any such mention.

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