Provably secure certificateless signcryption scheme without pairing

Certificateless signcryption (CLSC) is one of the most significant security primitives in CL-PKC, and at the same time achieves confidentiality and authentication by combining public-key encryption and digital signatures, offering better overall performance and security. There are two pairing-free CLSC schemes, which aim at reducing the computing costs by removing pairing. Moreover, these schemes adopt much modular exponential operations, which degrade its computation performance. This paper proposes a new CLSC scheme without pairing, and analyzes its security using random oracles under the computational Diffie-Hellman assumption. It shows that the new scheme is more efficient than all previous constructions.