Subject: RE: Possible solution?

From: "David P. Kemp" <[email-masked]>
Date: Wed, 11 Aug 1999 16:51:40 -0400 (EDT)

> From: Tony Bartoletti <[email-masked]>
> 
> But of course, this is nothing more than what is meant by "authentication"
> in digital signatures.  So, unless someone can explain how "technical
> non-repudiation" is more than this, it is a misleading redundancy (IMHO).
> 
> Someone distinguish "technical NR" from "technical authentication" for me,
> and I'll will stand corrected.

There is a distinction to be made between entity authentication
(H.A.C. Definition 1.45) and data origin authentication (Definition
1.48).  There is also a distinction between two-party authentication
and digital signatures (Definition 1.41, involving a set of messages
M, a set of signature values S, a signing transformation M->S, and
a verification transformation MxS -> {True, False}).

I would agree that "technical NR" is a synonym for the combination of
data authentication and digital signature.  If you leave out either
the data (persistence) or the signature (proof to a third party), you
don't have technical NR.

---

From: Tony Bartoletti <[email-masked]>
Date: Wed, 11 Aug 1999 14:50:06 -0700

>the data (persistence) or the signature (proof to a third party), you

OK.  I stand corrected (or at least clarified;)  

I take "data authentication" to mean, "cryptographically tamperproofed",
and "digital signature" to be the verifiable output of the "signature-
algorithm-collision" of (private) signature key with the data in question.

If this is what is meant (I must read the H.A.C. definitions) then
I agree that this is "technical NR".  The point is, it would seem
to be uninvolved with issues of private key ownership and protection.

That is, a private key could be "made public", anyone could use it
to sign anything, and the assumed cryptographic strength of the
algorithms assures us that, given the triple (data,publicKey,digSig)
we cannot "repudiate" that "data met the private Key" somewhere,
and this is "technical NR".

Anyway, thanks to the pointers to those definitions.

Regards,

___tony___

Tony Bartoletti                                             LL
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