RE: [pkcs11] CKA_PUBLIC_KEY_INFO

["Burns, Robert" <Robert.Burns@thalesesec.com>]

Title: RE: [pkcs11] CKA_PUBLIC_KEY_INFO

Agreed, but if you're waiting on the OASIS version of PKCS 11 to
come out with this new functionality, that sizable organization
already has this problem and is going to have fix it regardless!
(Unless of course they've already implemented the SPKI solution and
this just codifies it????). So why not just tell them to distribute
the public key too and they have a fix before this version is
ready?

Bob






-----Original Message-----
From: Peter Gutmann [pgut001@cs.auckland.ac.nz]

Sent: Wednesday, April 17, 2013 04:38 PM Eastern
Standard Time
To: msj@nthpermutation.com; pgut001@cs.auckland.ac.nz;
Burns, Robert
Cc: pkcs11@lists.oasis-open.org
Subject: RE: [pkcs11] CKA_PUBLIC_KEY_INFO

"Burns, Robert" <Robert.Burns@thalesesec.com> writes:

>Sorry for the late response -- traveling.

Ditto.  (But I bet I'm travelling further than you :-).

>I'm having difficulty imagining other use cases where a user will only have
>access to the private key, yet needs access to the public bits as well. I do
>understand your experiences with tokens which fit this mold, but the error
>(it seems) is in the fact that the token distributors were not also including
>the public key object as well?

The problem is that this is a sizeable organisation, and it's not the only one
that's doing it.  Two days ago I had a discussion with someone who's resorted
to trial-signing (enumerate every key on the token and generate a signature
with it) to identify which private key an incoming certificate corresponds to,
because they can't read the public-key components from the token in order to
match the key to the cert.  This just seems an unneccessarily painful way to
have to do things.

>So is the problem really that there are definite cryptographic reasons for
>needing the public key attributes on a private key, or is this just a
>convenient way to solve the problem that token vendors have introduced by not
>providing enough objects on their tokens?

Well, you can't really blame the vendors and leave it at that, "just redeploy
a million tokens and get it right this time round", not being able to recreate
a public key from a private-key object is something that's going to keep
biting people again and again, it's just the universality of RSA that's
currently masking the problem.

Peter.