Subject: Re: NR -- what the real issues are, and a proposal

From: Ivan Milman <[email-masked]>
Date: Wed, 18 Aug 1999 18:31:47 -0500

Bob J - >>
Bob B - >

>>My proposal is that the text of the nonrepudiation key usage bit I
>>n the PKIX RFC (and hopefully in X.509) be revised to unambiguously
>>state that the defined semantics of this bit is to indicate the willingness
>>of the subscriber to be legally bound by a digital signature which can be
>>verified by a certificate that can be established to have been valid at the
>>time of signature, where "valid" has the normal meaning of not expired, not
>>revoked, etc., etc.

>I think this is a good choice of semantics for the key usage bit, but I have
>some questions about how it's implemented.  Specifically, I want to know
>by whom the bit is going to be set, and on the basis of what assurances.
>You clearly don't want a CA to be creating certs. with this bit set and handing
>them out to people without prior authorization, because if such a cert and
>its corresponding private key got sent to the wrong person for any reason,
>it would be an instrument which could legally bind someone else.  I think people
>are going to want to have a record that they authorized the creation of such
>a liability-bearing instrument -- they might even want to set the bit themselves,
>in some sense.  Perhaps we'd have to look at a two-stage process, whereby
>a non-binding cert would be generated and distributed, and then a request
>for a binding cert would be generated and signed using the non-binding cert...

Presumably the user/RA/CA could archive the CRMF message where the NR bit was
set.

Ivan M. Milman	Technical Director	DASCOM Austin
email:  [email-masked]		Phone:  1-512-458-4037, ext. 5014

---

From: Timothy Fisher <[email-masked]>
Date: Wed, 18 Aug 1999 19:38:52 -0700

Can anyone point me to a reference where I might be able to find implementation
details for implementing the CAST5-MAC algorithm?
I have looked at RFC2144 which is the RFC for CAST, but it does not contain details
for implementing the MAC version of CAST.   That is what I am interested in.

If you can be of help, or point me to an appropriate reference/specification I would
be greatful.

Sincerely,
Timothy Fisher
[email-masked]