Re: [Trans] Precertificate format

Rob Stradling <> Tue, 28 October 2014 13:44 UTC

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Date: Tue, 28 Oct 2014 13:43:41 +0000
From: Rob Stradling <>
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Subject: Re: [Trans] Precertificate format
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On 25/10/14 17:51, Russ Housley wrote:
> I think you are suggesting the format used in a .p7c file.  If I understand correctly, I fully support this idea.

Hi Russ.  It's similar to .p7c in that it uses the SignedData structure.

 From RFC5652...
SignedData ::= SEQUENCE {
         version CMSVersion,
         digestAlgorithms DigestAlgorithmIdentifiers,
         encapContentInfo EncapsulatedContentInfo,
         certificates [0] IMPLICIT CertificateSet OPTIONAL,
         crls [1] IMPLICIT RevocationInfoChoices OPTIONAL,
         signerInfos SignerInfos }

A .p7c is a SignedData structure that contains one or more 
"certificates", but nothing useful in "encapContentInfo" or "signerInfos".

What we're proposing is a SignedData structure that contains zero or 
more "certificates" (CA certificates only), the TBSCertificate in 
"encapContentInfo" and a signature from the CA in "signerInfos".

We'll need to define a new ContentType OID that means "TBSCertificate".

> Russ
>> We (the 6962-bis editors) would like to propose that we replace the existing precertificate formats with a TBSCertificate wrapped in PKCS#7. This lays to rest, we think, any possible confusion with X509v3 certs, whilst allowing a simple mapping between the final cert and the pre-cert.
>> Obviously there are details to be nailed down, but before we do so, we'd like to hear any discussion on the general idea.
> _______________________________________________
> Trans mailing list

Rob Stradling
Senior Research & Development Scientist
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