missing dsa factor
Bob Mathews
bobmathews at mindspring.com
Thu Feb 28 08:20:01 CET 2002
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1
I've been looking at the factor entries that are stored in the secret ring
file, and it seems that there is one missing from DSA keys. When I start with
(p-1)/2 and divide off q and the other given factors, I'm still left with a
large composite number.
In gen_elg_prime(), prime is calculated as:
2 * q * q_factor * factor[0]..factor[n-1] + 1
But when the ret_factors array is populated, it gets:
q_factor, factor[1]..factor[n]
(It appears that factor[n] will always be NULL.) That leaves q and factor[0]
both unknown. This behavior is in 1.0.6c, and doesn't appear to have been
fixed in CVS.
Should be a trivial fix.
if( mode == 1 ) {
(*ret_factors)[i++] = mpi_copy( q_factor );
for(; i <= n; i++ )
- (*ret_factors)[i] = mpi_copy( factors[i] );
+ (*ret_factors)[i] = mpi_copy( factors[i-1] );
}
Since the factors aren't currently used for anything, the missing one
shouldn't hurt anything. It'll be disappointing if someone ever wants them
for something, though.
-bob mathews
-----BEGIN PGP SIGNATURE-----
Comment: What's this? http://bobmathews.home.mindspring.com/bob/
iD8DBQE8fdiwPgDecCrBEpcRAjYkAJ4lyFOvVCjUXiZO5LZs7tMzaQMe5gCdGfxT
orJ8kPU1VcAkKxxtiQ71Dqg=
=5Ddq
-----END PGP SIGNATURE-----
More information about the Gnupg-devel
mailing list