DSA Implementation in GnuPG

[David Shaw]

On Jun 17, 2009, at 8:54 AM, Stefan Lorenz wrote:

> Hi there,
>
> we are interested in the actual implementation of DSA in GnuPG, in  
> particular we would like to know whether the primes p, q and the  
> generator g are or can somehow be fixed during the key generation.  
> Additionally we would like to know how the size of q is determined.

Not in GnuPG directly, but I believe you can access this via gcrypt,  
which is what GnuPG uses for its crypto.

In GnuPG, 'q' is chosen based on the size of the key: if the key is  
over 2048 bits long, q is 256 bits.  If the key is over 1024 bits  
long, q is 224 bits.  If the key is 1024 bits or less, then q is 160  
bits.

David