An Improvement of ElGamal Digital Signature Scheme

ElGamal digital signature scheme was analyzed. To overcome the shortage of ElGamal signature without message recovery, it was improved. Moreover, a kind of digital signature scheme with the function of message recovery was proposed. The security of the new scheme is based on the difficult solution of discrete logarithm on limited domain, which is as same as that of ElGamal signature scheme. Then, methods for message recovery had been discussed and a new optimized method to recover message was presented. Finally, the security of the improved scheme was analyzed, and the study demonstrated that the security of the improved scheme was better than that of the old one.