Integer Factorization by a Parallel GNFS Algorithm for Public Key Cryptosystems

RSA is a very popular public key cryptosystem for encryption and authentication. The security of RSA mainly relies on the difficulty of factoring large integers. Recent advancement in factoring algorithms have made it possible to factor integers with 150-digits or more. The General Number Field Sieve algorithm (GNFS) is currently the best known method for factoring large numbers over 110 digits. Although the GNFS algorithm is efficient, it still takes a long time to factor a large integer such as an integer with 150-digits or larger. In this paper, we present a parallel GNFS implementation on a SUN-cluster. It can successfully factor integers up to 116 digits very quickly. The experimental results have demonstrated that the algorithm achieves good speedup and can be used for further larger integer factorization.