Subject: Poll on draft-farrel-pkix-other-certs-02

From: Denis Pinkas <[email-masked]>
Date: Sat, 05 Jul 2008 10:21:58 +0200

NO.

It has been requested and acknowledged that the new draft would mention the
relationship with RFC 4043. The draft still does not mention any
relationship with RFC 4043 (Permanent Identifier) :

"The permanent identifier is an optional feature that may be used by a CA 
to indicate that two or more certificates relate to the same entity, even if 
they contain different subject name (DNs) or different names in the 
subjectAltName extension, or if the name or the affiliation of that entity 
stored in the subject or another name form in the subjectAltName extension 
has changed".

The scheme described in the draft proposal is subject to attacks, 
since any CA (as long as it belongs under the tree from a root CA) 
could claim that a new web site is the continuation of another. 
Then phishing would be quite easy to get the id and the password 
of the original web site and use them to access it.

It is yet-another-extension able to achieve roughly the same purpose 
as RFC 4043. Under which circumstances could RFC 4043 be used ? 

Since the PI must be placed in the original certificate, this mandates 
the revocation of the current web certificate and to replace it by a new one 
that is identical, except that it includes a PI. This approach offers 
all the properties that are looked for, as long as the new certificate 
is issued by the same CA. Since the same CA is involved, no cheat by 
another CA is possible.

The limitation is that it does not allow to dynamically change the CA, 
but in such a case there are security problems as mentioned above.

Denis