Re: [OAUTH-WG] [EXTERNAL] Re: OAuth 2.1 - require PKCE?

Neil Madden <neil.madden@forgerock.com> Mon, 11 May 2020 06:47 UTC

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From: Neil Madden <neil.madden@forgerock.com>
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Date: Mon, 11 May 2020 07:47:54 +0100
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Cc: Dick Hardt <dick.hardt@gmail.com>, Mike Jones <Michael.Jones@microsoft.com>, "oauth@ietf.org" <oauth@ietf.org>
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To: Torsten Lodderstedt <torsten@lodderstedt.net>
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Subject: Re: [OAUTH-WG] [EXTERNAL] Re: OAuth 2.1 - require PKCE?
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> On 11 May 2020, at 07:41, Torsten Lodderstedt <torsten@lodderstedt.net> wrote:
> 
>> On 11. May 2020, at 07:38, Neil Madden <neil.madden@forgerock.com> wrote:
>> 
>> There is no attack that this prevents so your claim of improving security is unsubstantiated. I can’t see how we can ship a 2.1-compliant-by-default AS while this requirement remains so I don’t support it. 
> 
> Are you saying PKCE does not prevent any attack?

No, but servers and clients are already free to support PKCE. I’m saying that rejecting requests from non-PKCE clients doesn’t prevent any attack. It just denies service to legitimate clients. 

— Neil