Re: [Trans] OCSP and SCTs

Brian Smith <brian@briansmith.org> Sat, 30 August 2014 22:43 UTC

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Date: Sat, 30 Aug 2014 15:43:17 -0700
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From: Brian Smith <brian@briansmith.org>
To: Fabrice <fabrice.gautier@gmail.com>
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Subject: Re: [Trans] OCSP and SCTs
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On Sat, Aug 30, 2014 at 3:22 PM, Fabrice <fabrice.gautier@gmail.com> wrote:
>> On Aug 30, 2014, at 14:16, Brian Smith <brian@briansmith.org> wrote:
> I understand the issue you describe and how stapling has less opportunities for failures and is a MUST for TLS clients, but my question was really about what should a TLS client do when it does not get an OCSP response through stapling (RFC6066) but get one directly from the OCSP responder or potentially other means.
>
> To me, it seems logical for the TLS clients to process SCTs found in those responses, no matter how it got them.

When the client is enforcing CT, it should reject the certificate due
to the missing SCT before it even attempts revocation checking. Thus,
it would never fetch the OCSP response and so it would never learn the
SCT from a fetched response.

Cheers,
Brian