Re: [Trans] [trans] #79 (rfc6962-bis): Precertificate signaturemust be over something other than just the TBSCertificate

[Stephen Kent <[e-mail]>]

Rob,
> On 11/06/15 22:42, Stephen Kent wrote:
>> what does it mean to not be "an X509 signature"?
>>
>> I thought the intent was to use a CMS object, and thus the signature
>> would be defined by that (profiled) CMS object.
>
> Hi Steve.  That's correct.
>
> At the top of ticket #79 I wrote:
> "If I understand the CMS spec correctly, then we're currently defining 
> a Precertificate to be a CMS structure that contains a TBSCertificate 
> and a signature over just that TBSCertificate.
> That means that the components of a Precertificate can be trivially 
> rearranged into an X.509 certificate with a valid signature!"
>
> It turns out that I didn't understand correctly.  :-)
happens to all of us ;-)
>
> Ben added some text to help clarify the situation:
> "Note that, because of the structure of CMS, the signature on the CMS 
> object will not be a valid X.509v3 signature and so cannot be used to 
> construct a certificate from the precertificate."
I might say: "The signature on the CMS structure used to convey a 
pre-certificate
is not the same as the signature that appears in the X.509 certificate, 
per se."

Steve