Nikos Mavrogiannopoulos <[email protected]> writes:
> I tried to switch gnutls to use dsa_generate_keypair() to generate
> primes for the DH key exchange, but unfortunately this interface has the
> strict DSS checks for q_bits.
I'm not sure what's the right thing is here.
Simplest would be to just drop these requirements from
dsa_generate_keypair, and let it do whatever the caller asks for. Do you
think that makes sense?
> Would it be possible to have a dh_generate_keypair() that does the
> exact same thing without the q_bits and p_bits limitations?
Do you need exactly the same thing for DH? I.e., a group of relatively
small size q, which is a subgroup of Z_p^* for some much larger p?
I imagine one might want to rather use primes like p = 2q + 1 or so, so
the size q subgroup is almost as large as Z_p. I'm not sure the current
code works with q_size = p_size-1.
Related issue, which soemone else asked about some week ago, is
separating generation of DSA parameters (i.e., p, q, g) from generation
of the key pair. Currently, there's no easy way in nettle to generate a
key for some pre-specified DSA group. It might be better to have
something like
struct dsa_params
{
mpz_t p;
mpz_t q;
mpz_t g;
};
struct dsa_private_key
{
const struct dsa_params *params;
mpz_t x;
};
struct dsa_private_key
{
const struct dsa_params *params;
mpz_t y;
};
(a bit analogous to the new ecdsa code). But that would be a pretty
large and incompatible change, so we maybe shouldn't do that, or at
least think carefully about compatibility.
Regards,
/Niels
--
Niels Möller. PGP-encrypted email is preferred. Keyid C0B98E26.
Internet email is subject to wholesale government surveillance.
_______________________________________________
nettle-bugs mailing list
[email protected]
http://lists.lysator.liu.se/mailman/listinfo/nettle-bugs
