Scott - We agree. The current draft makes it mandatory to use a different
key. I am arguing that the same key should be permitted.
I am also arguing that a non-keyed digest procedure that results in a string
that can be unambiguously recited over the telephone is called for. This
means that it should have only upper-case letters and numbers, be separated
into chunks of 3 or 4 characters (like a North American phone number) and be
no longer than (say) 16 characters.
All the best. Tim.
-----Original Message-----
From: Scott Cantor [mailto:]
Sent: Wednesday, July 09, 2003 11:20 AM
To: 'Tim Moses';
Subject: RE: [security-services] Metadata for 1.1 Web Browser SSO
Profile, Draft 06, 1 May 2003
> In the case where the key distributed with the metadata is a
> public signature-verification key, it is acceptable,
> desirable and conventional to sign the metadata using the
> corresponding private key. This is common practice for X.509
> certificates. In addition, it allows the integrity of the
> metadata to be confirmed using an out-of-band "digest".
It shouldn't be mandatory to use the same key, since that basically only
permits point to point trust.
> As currently required, the integrity of the metadata has to
> be protected with a separate key. Presumably, it too has
> associated metadata that has to be distributed, protected
> with another key, which (in-turn) has metadata. Allowing the
> enclosed key to confirm the integrity of the metadata, breaks
> this cycle.
PKI always has an arbitrary stopping point somewhere. It's ok to allow it to
be self-signed, but we shouldn't insist on it.
> Here is a suggestion for a digest procedure:
Umm, why not XML signature?
-- Scott
