An Improved ElGamal Digital Signature Algorithm Based on Adding a Random Number

With the wide application of ElGamal digital signature scheme, its security is usually being challenged and the problem becomes increasingly serious. In order to resolve the security decline caused by the ElGamal signature scheme which uses only one random number, a modified scheme was proposed in this paper. It adds a random number to the scheme in order to increase the difficulty of deciphering key, and therefore improves the security correspondingly. As same as the ElGamal signature scheme, the improved signature scheme is also based on the difficulty in discrete logarithm finite field. Eventually the improved signature scheme was analyzed on security and time complexity. The analysis shows that the security of the improved signature scheme is higher than original one, and has a relatively low time complexity.