A few sentences from the Master and the lights started going on.  As
soon as I read your email I realized how I was confused.  What I
actually needed to do was pass the message directly to NR<*>, instead of
hashing it first and passing the hash.

Many thanks.

-----Original Message-----
From: Wei Dai [mailto:[EMAIL PROTECTED] 
Sent: Friday, November 04, 2005 1:49 PM
To: [email protected]
Subject: Re: Digest Signature Scheme


"Digest signature" allowed you to sign a digest directly, without hasing
it 
again. This is no longer directly supported, but you can accomplish the
same 
thing by creating a dummy "hash" algorithm that just returns the input 
without actually hashing it. To create DummyHash, override 
HashTransformation and implement the 3 pure abstract functions Update, 
DigestSize, and TruncatedFinal. It should be pretty obvious how to do
that 
so I won't go into details. Then you can use NR<DummyHash>.

----- Original Message ----- 
From: "Bill Shanahan" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Thursday, November 03, 2005 11:27 AM
Subject: Digest Signature Scheme


>
> It looks to me that in the 5.2 library, there are no equivalents to 
> the 5.0 calls
>
> NR<SHA>::Verifier::GetDigestSignatureScheme()
> NR<SHA>::Signer::GetDigestSignatureScheme()
>
> It looks like digest signatures are deprecated, but I have to maintain

> backward compatibility.  So it looks like I can't upgrade to 5.2 yet.

> I need to have a version of my software that reads digest signatures 
> but writes message signatures.  I can use 5.0 to make that.  Then 
> after a while I can release a 5.2 upgrade and deprecate the old file 
> format.
>
> Do I understand correctly?
>
> 





Reply via email to