Re: Suggested changes for DSA2

[Jon Callas <[e-mail]>]

On 27 Mar 2006, at 7:44 AM, Daniel A. Nagy wrote:

> I agree with David here. The standard's purpose is to ensure
> interoperability. It should tell us the sematics behind sequences  
> of bytes.
> It is up to the implementation to make decisions based on these  
> semantics.
> Valid reasons to exclude certain combinations from the standard  
> include
> ambiguity of interpretation, inherent insecurity or a wide  
> installed base of
> incompatible implementations, but not the possibility of weird  
> uses, IMHO.
>

I agree as well with both Davids.

As an observation, in 2440 one of the things we allowed was deviation  
from DSS because the rough consensus had a certain amount of  
grumpiness with the US Government. In practice, hardly anyone did  
anything different with DSA than DSS. We even removed hash functions.

Many things have changed in the last decade, but toeing the exact  
NIST line or even being like them only moreso is going a bit too far.  
In the next decade, we're going to see a lot of advancement in hash  
functions. Someone is going to want to use those new hash functions  
with DSA, and it would be nice to be able to move faster than NIST.

Let's suppose someone comes up with a new hash function that is 251  
bits. (I picked 251 because it's prime and less than 256.) We don't  
want a constitutional crisis over using it. We want to be flexible  
enough that it's pretty obvious how to extend OpenPGP to use new hash  
functions with DSA.

	Jon