Security Analysis and Improvement of Hybrid Signcryption Scheme Based on Heterogeneous System

The heterogeneous hybrid signcryption scheme can not only solve the problem that only the short message can be encrypted in the traditional public key signcryption, but also realize the secure communication between different cryptosystems. Firstly, the security analysis of a heterogeneous hybrid signcryption scheme shows that the scheme does not satisfy confidentiality and unforgeability. In order to enhance security, an improved heterogeneous hybrid signcryption scheme is proposed. Based on the bilinear Diffie-Hellman problem and discrete logarithm problem, the new scheme is proved to satisfy confidentiality and unforgeability. Compared with the original solution, the new solution reduces the computational overhead while improving security.