1. New directions in cryptography;Diffie;“IEEE Trans. Inform. Theory”,1976
2. A method for obtaining digital signatures and public key cryptosystems;Rivest;“Commun. ACM”,1978
3. A public key cryptosystem and a signature scheme based on discrete logarithms;Eìamal;“IEEE Trans. Inform. Theory”,1985
4. A proposed federal information processing standard for digital signature standard (DSS) 1991
5. U.S. Department of Commerce, National Bureau of Standards Data encryption standard 1977