Subject: 3280bis: KeyUsage NR/CC bit

From: "Denis Pinkas" <[email-masked]>
Date: Thu, 28 Jul 2005 11:10:08 +0100

Extract from: draft-ietf-pkix-rfc3280bis-01.txt :

« The nonRepudiation bit is asserted when the subject public key 
is used to verify digital signatures, other than signatures on 
certificates (bit 5) and CRLs (bit 6), used to provide a non-repudiation 
service which protects against the signing entity falsely denying 
some action. In the case of later conflict, a reliable third party may 
determine the authenticity of the signed data ».

I can live with the proposed ASN.1.

I would however suggest to re-use some of the key words of X.509.
In the last sentence "authenticity of the signed data" may be misleading 
since it is missing the notion of time.  

Proposal for a compromise with X.509 2000)/Cor.3 (04/2004): 

" The nonRepudiation bit is asserted when the subject public key 
is used to verify digital signatures, other than signatures on 
certificates (bit 5) and CRLs (bit 6), which are intended to signal 
that the signer is committing to the content being signed.  
In the case of later conflict, this allows to provide a non-repudiation 
service which protects against the signing entity falsely denying some action ».

Denis

PS: The original text from the TC of X.509 is:

b) contentCommitment: for verifying digital signatures which 
are intended to signal that the signer is committing to the content being signed. 
The precise level of commitment, e.g. “with the intent to be bound” 
may be signaled by additional methods, e.g. certificate policy.

Since a content commitment signing is considered to be a digitally signed 
transaction, the digitalSignature bit need not be set in the certificate. 
If it is set, it does not affect the level of commitment the signer has 
endowed in the signed content.

Note that it is not incorrect to refer to this keyUsage bit using the 
identifier nonRepudiation. However, the use this identifier has been 
deprecated. Regardless of the identifier used, the semantics of this 
bit are as specified in this standard.

---

From: "Kazin, Joel" <[email-masked]>
Date: Thu, 28 Jul 2005 08:20:30 -0500

At 05:10 AM 7/28/2005 -0500, Denis Pinkas wrote:

service which protects against the signing entity falsely denying some
action ». 

Perhaps the following wording is better:

The contentCommitment bit is asserted when the subject public key 
is used to verify digital signatures, other than signatures on 
certificates (bit 5) and CRLs (bit 6). It is intended to signal 
that the signer is intending to committ to the content being signed.  
In the case of later conflict, this may help a non-repudiation 
service provider to determine if the subject's claimed repudiation is true
or false.

Denis 

b) contentCommitment: for verifying digital signatures which 
are intended to signal that the signer is committing to the content being
signed. 
The precise level of commitment, e.g. with the intent to be bound 
may be signaled by additional methods, e.g. certificate policy. 

Joel S. Kazin CPA, CISA, CISSP, CISM
Senior Consultant
Atos Origin
40 Old Sleepy Hollow Road
Pleasantville, New York 10570-3802
USA
Phone  +1 914-769-8780
Mobile  +1 914-564-1484
email    [email-masked]
www.atosorigin.com <http://www.atosorigin.com/>

---

From: "Denis Pinkas" <[email-masked]>
Date: Thu, 28 Jul 2005 16:45:58 +0100

Joël,

>service provider to determine if the subject's claimed repudiation is true

There would need to have the first and second sentence bundled together, 
which means changing:
 
" (bit 6). It is intended " 
into 
" (bit 6) and is intended ".

The end result would be:

certificates (bit 5) and CRLs (bit 6) and is intended to signal 

Denis

---

From: "Kazin, Joel" <[email-masked]>
Date: Thu, 28 Jul 2005 10:01:33 -0500

That is fine.

At 10:45 AM 7/28/2005 -0500, Denis Pinkas wrote:

Joël, 

  

The end result would be: 

Denis 

>www.atosorigin.com <http://www.atosorigin.com/>
<http://www.atosorigin.com/ <http://www.atosorigin.com/> >