Subject: Re: Signing what you don't understand: a practical example

From: [email-masked]
Date: Wed, 12 Jul 2000 12:07:39 -0400

Hi Aram:

     Response below.

          Tom

Aram Perez <[email-masked]> on 07/11/2000 09:35:54 PM

To:   PKIX <[email-masked]>
cc:
Subject:  Re: Signing what you don't understand: a practical example

Hi Tom,

> For Denis' technique to have any real use, there would also need to be
> an indicator somewhere in the certificate that "the private key of this
> pair is held in a Bider-compliant smart card".  Doing that (and it could
go
> into any of several extensions, or a new one could be defined), is
> considerably easier than changing the signature format.

But how does the CA know that I'm using a "Bider-compliant smart card"
(BCSC)? Do I have to physically show up somewhere with my BCSC to prove
that I have one? Since the BCSC isn't fully specified, I don't know if it
allows me to keep a backup copy of my signature key. If it does, then I
might/probably could feed the backup into a software only system.

[Tom Gindin] The same problem exists with current smart cards, but some
people are putting indicators that a key is on a smart card into their
certificates already.  Either the CA generates the key on and delivers the
smart card, or the user shows up with card in hand.  Hopefully, a BCSC
would not allow signature key backup.

Regards,
Aram Perez

[snip]

---

From: Aram Perez <[email-masked]>
Date: Wed, 12 Jul 2000 09:28:44 -0700

Hi Tom,

> would not allow signature key backup.

When you say "some people are putting indicators that a key is on a smart
card into their certificates already", does the CA check that fact? Who's
liable if the indicator is positive when in fact I have no smart card? If
the CA generates the key, how do I know the CA doesn't keep a copy?

Regards,
Aram Perez