Diffie-Hellman 128 bit

[Anton Stiglic]

> Well, I'm attacking a protocol, I know the rules of DH parameters, and the
> issue here is I'm trying to solve x, brute forcing that in the 128 bit
range
> can be difficult, and x doesn't have to be a prime. (a = g^x mod P). Their
> primes are 128 bit primes, as well as their pubkeys, I've done some tests
on
> their prime, and all perform under this method of (p-1)/2 = prime. This
> eliminates the pohlig-hellman discrete logarithm attack, but I'm trying to
> learn the Gaussian integer method.

No, just use the Number Field Sieve algorithm (this is mentioned in section
3.5 of the manuscript I gave you the link to).
You could read section 3.6 of the Handbook of Applied Cryptography for
a basic introduction to the problem of discrete logarithm.

--Anton


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