①College of Information Technical Science, Nankai University, Tianjin 300071, China; ②State Key Laboratory of Information Security, Beijing 100049, China
Abstract:In this paper, a new signcryption scheme called CPK-SC is proposed based on Combined Public Key (CPK) to resolve the authentication and non-repudiation problem. CPK-SC discards the pairings and solves the restriction that the traditional identity-based signcryption schemes can only deal with fixed length messages by introduction symmetric cryptography algorithm. CPK-SC spends fewer computations and produces shorter ciphertext, which can be widely used in the environment of computation and communication resource constrained, such as mobile ad-hoc network. In the random oracle model, the security of CPK-SC is tightly related to the Decision Diffie-Hellman (DDH) assumption.