[cabfpub] Mozilla SHA-1 further restrictions

[Wayne Thayer]

>> Of course the best answer should be to completely ban SHA1. But since
>> we're struggling with legacy stuff, my proposal would be to ban SHA-1
>> OCSP signing from a CA key, and instead use a designated OCSP
>> responder certificate for such responses.

> Do other CAs have comments on the level of disruption that such a
> mandate might cause? AIUI, if this were required, then a SHA-1 collision
> using an OCSP response could only be used to fake another OCSP response.
> Which sounds like good risk reduction.


This seems entirely reasonable and prudent to me. And Microsoft requires it anyhow:

A CA must either technically constrain an OCSP responder such that the only EKU allowed is OCSP Signing or it must not use SHA-1 to sign OCSP responses.

Wayne
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