Re: Last Call: draft-ietf-pkix-new-part1-06.txt comments

["David P. Kemp" <dpkemp@xxxxxxxxxxxxxx>]

The 9:25 AM version was clearer.  This version adds a restriction on
which type of authority may sign which type of revocation list.  Neither
version defines "CA certificate"; my impression was that

  If the cA bit is set, then the certificate *is* a CA certificate,

not the backwards-sounding

  If the cRLSign bit is asserted in a CA certificate, then the cA bit
  MUST be asserted.


How about the following:

      The cRLSign bit is asserted when the subject public key is used
      for verifying a signature on a CertificateList (e.g., a CRL).
      If the cA bit in the basic constraints extension (see 4.2.1.10)
      is not asserted, then the public key MUST NOT be used to verify
      signatures on CRLs containing revocation information for public
      key certificates, however it may be used to verify signatures
      on CRLs containing revocation information for other types of
      certificates (e.g., attribute certificates).
   *  If the cA bit is asserted, then the public key MUST NOT be used
   *  to verify signatures on CRLs containing revocation information
   *  for certificates other than public key certificates.

      If the keyCertSign bit is asserted, then the cA bit in the basic
      constraints extension MUST be asserted.  If neither the cRLSign
      bit nor the keyCertSign bit are asserted, then the cA bit in the
      basic constraints extension MUST NOT be asserted.


The third sentence (marked ***) is new; I don't know if you intended
the asymmetry of allowing CAs to revoke ACs but forbidding AAs from
revoking PKCs.  If neither CAs nor AAs can revoke the other's certs,
then the third sentence is needed.

Dave



Stephen Farrell wrote:
> 
> I thought it was clearer first time! But its still ok.
> 
> Stephen.
> 
> Russ Housley wrote:
> >
> > Tim Polk and I just got off the phone.  After a lengthy discussion, we
> > propose a revision to the cRLSign discussion:
> >
> >        The cRLSign bit is asserted when the subject public key is used
> >        for verifying a signature on revocation information (e.g., a CRL).
> >        This bit MUST be asserted in CA certificates that are used to
> >        verify signatures on CRLs.  If the cRLSign bit is asserted in a CA
> >        certificate, then the cA bit in the basic constraints extension
> >        (see 4.2.1.10) MUST also be asserted.  If the cRLSign bit is
> >        asserted in a non-CA certificate, then the cA bit in the basic
> >        constraints extension MUST NOT be asserted.  Such non-CA
> >        certificates MUST NOT be used to verify signatures on CRLs
> >        containing revocation information for public key certificates;
> >        however, these non-CA certificates MAY be used to verify
> >        signatures on CRLs containing revocation information concerning
> >        other types of certificates (e.g., attribute certificates).  If
> >        neither the cRLSign bit nor the keyCertSign bit are asserted, then
> >        the cA bit in the basic constraints extension MUST NOT be
> >        asserted.
> >
> > Hey, this section was only one sentence in RFC 2459...
> >
> > Please let us know if anyone has any remaining concerns.
> >
> > Russ