关键词: 无证书, 代理, 数字签名, 替换公钥攻击, 双线性对

Abstract: The certificateless proxy signature scheme proposed by Fan Rui etc. was analyzed and their scheme turned out to be insecure. Furthermore, a serious security flaw was discovered in the proxy key generation algorithm, because the private key of the original signer could be recovered by the proxy signer. Unfortunately, the same security flaw was also found out in other proxy signature schemes. Finally, a comprehensive and improved scheme was proposed, whose security was based on the Computational Diffie-Hellman Problem (CDHP).

Key words: certificateless, proxy, digital signature, public key replacement attack, bilinear pairings