x509 v1 certificate

[Werner Koch]

On Mon, 25 Sep 2006 02:35, Kazu Yamamoto (山本和彦) said:

> Yes, RFC3280 is not readable but the "certificates" in Section 4
> refers "intermediate" CA's ones only, dos not refer to root CA's ones.

The nice thing with X.509 is that there are so many possible
interpratations and that even profiles even add more possible
translations.  Well, we know all that :-(

Gpgsm has been build and certified for a German profile which is based
on PKIX but has some more restrictions.  That is the spo called Sphinx
profile.  We now tend to adhere to the newer ISIS-MTT profile which
should be fully compatible with PKIX but isn't at some places.

> Yes, RFC3280 is not readable but the "certificates" in Section 4
> refers "intermediate" CA's ones only, dos not refer to root CA's ones.

Sorry, I am not able to read this from rfc3280.  To quote it again:

   This extension MUST appear as a critical extension in all CA
   certificates that contain public keys used to validate digital
   signatures on certificates.  This extension MAY appear as a critical

The root certificates has the public key to verify the intermediate
certificate. The ISIS-MTT profile says:

   This extension MAY appear in end entity certificates and MUST
   appear in CA certificates. It MUST be marked critical.

Thus stating only that an EE certificate is allowed to carry a
BasicContraints extension.  It does not say anoything about the root
certificate.  Your interpretation is that a root certificate is not a
CA certificate.  My interpretation is that a root certificate has the
public key and thus is a CA certificate used to verify a signature.  I
an see now other way to verify a signature without having a public
key.  Section 6 may or may not contradict this but the specification
of the certificates in section 4 states that a root certificates
requires a BasicConstraint.

BTW, using root certificates based on MD5 is highly questionable and
alone good reasons to not support those v1 root certificates.


Shalom-Salam,

   Werner