RE: CA=True for an OCSP certficat

[Stephen Kent <kent@xxxxxxx>]

Title: RE: CA=True for an OCSP certficat

At 8:15 PM -0400 4/2/08, Santosh Chokhani wrote:

> Steve,
>
> I agree with you the time stamp server.
>
> But, under RFC 2560, one of the model is for the CA (and I
> interpret
> that to mean using the same key that signed the certificate whose
> revocation status is being checked) to sign the OCSP response.  
> Hence
> CA certificate signing key can be used
> for OCSP signing.

Whoops, you're right. I had not looked at 2560, but 4.2.2.2 says explicitly that the response can be signed using the same key that was used to issue the cert, the status of which is being checked (although it sates this in a rather backwards fashion :-)).

Peter also pointed me to text in 3280, in the discussion of Basic Constraints that clearly indicates that it is OK for a CA cert to be used to verify non-cert and non-CRL data, in the case of cert enrollment protocols:

This extension MAY appear as a critical or non-critical extension in CA certificates that contain public keys used exclusively for purposes other than validating digital signatures on certificates.  Such CA certificates include ones that contain public keys used exclusively for validating digital signatures on CRLs and ones that contain key management public keys used with certificate enrollment protocols.

Steve