Aiming at characteristics of rigorous identity authentication for both two trading parties in network transactions and based on analysis and study on Hyper Elliptic Curve (HEC) and ElGamal based on discrete logarithm problem, these two approaches were combined organically to design a digital signature system based on HEC-ElGamal. It was applied in the identity authentication to provide bipolar signature verification. The security performance of this approach was also analyzed. This system of digital signature inherits security technology of two systems, so that it can reach high security index. It provides guarantee for integrity check and identity authentication.