Subject: RE: Meaning of Non-repudiation

From: "Trevor Freeman" <[email-masked]>
Date: Fri, 3 May 2002 13:09:30 -0700

Dave,
If you truly were just changing the names - I could not care one jolt,
but you are proposing changing the semantics, and that is unacceptable.
DS today means sign anything but certs and CRLS. That definition has to
stand for that bit.
Trevor

-----Original Message-----
From: David P. Kemp [mailto:[email-masked]] 
Sent: Friday, May 03, 2002 7:17 AM
To: [email-masked]
Subject: Re: Meaning of Non-repudiation

Olaf,

I concur as well.   Nothing needs to change about how the bit is used;
only its name needs changing.

Dave

Denis Pinkas wrote:
> 
> Olaf,
> 
> Thank you for these comprehensive explanations.
> 
> I concur.
> 
> Denis
> 
> > The NR bit in a certifiicate does not proof anything. It is a
statement
> > made by the signer and/or the CA about the intended use of the key.
> > KeyUsage bits are currently used to support key pair separation for
the
> > three basic use cases of public key cryptography: encryption,
> > authentication and digital signing. Most application choose public
key
> > certificates needed for a certain type of operation based on the
keyUsage
> > bits: with keyEncipherment to encrypt a message, with
digitalSignature to
> > verify the response to a challenge for authentication, or to verify
> > signature made on e-mail. These two bits are essential (and
sufficient) to
> > support key pair seperation per RSA operation capability (decryption
or
> > signing) of the private key as the RSA operation capabilities of
private
> > keys may be restricted by hardware implementation (i.e. a crypto
processor
> > card may be configured to allow only signing with a private key, or
> > decryption, and check padding and format of input/output before and
after
> > the operation or even include part or all of the hashing procedure).
> 
> > If one wants to ensure that a private key is only used to sign data,
but
> > not to sign an arbitrary challenge, (which practically means "can be
used
> > within S/MIME but not within SSL")  which is the case e.g. within
the
> > signature law compliant use cases, a new bit is needed to clearly
> > distinguish between public keys used for authentication and for
signature
> > verification. In all specs that adress this seperation the
nonRepudiation
-----------------------------------------------------------
> > bit is used for that purpose. And I cannot see a need for changing
that.
------------------------------------------------------------------------

---

From: "David P. Kemp" <[email-masked]>
Date: Mon, 06 May 2002 15:52:33 -0400

> DS today means sign anything but certs and CRLS. That definition has to

Trevor,

You can read the standard as well as anyone, and know that
DS today means sign anything but certs, CRLs, *and bit 1 stuff*.

This discussion is trying to de-fuzzy the definition
of bit 1 stuff.  Your claim that {bit 1 stuff} == {the empty set}
may reflect the behavior of some existing products.  And
it is definitely about as non-fuzzy as you can get :-).

But X.509 and 2459 say that, whatever bit 1 stuff is,
it is *not* the empty set.  The X.509 definition, not the
Trevor definition, is what must stand.

Dave