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

["trans issue tracker" <[e-mail]>]

#79: Precertificate signature must be over something other than just the
TBSCertificate

 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!

 To fix this, we need to either...

 1. Require the SignedData.encapContentInfo.eContent field to contain
 "something || TBSCertificate" or "TBSCertificate || something".
 or
 2. Require a signed attribute to be present in
 SignedData.signerInfos[0].signedAttrs.  This is essentially equivalent to
 "TBSCertificate || something" in terms of what gets signed.

 I think 2 is the cleaner solution, unless there's a cryptographic reason
 to prefer "something || TBSCertificate" (e.g. to protect against chosen
 prefix collisions?)

-- 
-------------------------------------+-------------------------------------
 Reporter:                           |      Owner:  draft-ietf-trans-
  [e-mail]           |  [e-mail]
     Type:  defect                   |     Status:  new
 Priority:  blocker                  |  Milestone:
Component:  rfc6962-bis              |    Version:
 Severity:  -                        |   Keywords:
-------------------------------------+-------------------------------------

Ticket URL: <http://trac.tools.ietf.org/wg/trans/trac/ticket/79>
trans <http://tools.ietf.org/trans/>