Abstract: Signcryption algorithm can realize encryption and signature functions at the same time in a logical step. Compared with the traditional scheme of signing first and then encrypting, signcryption algorithm has the advantages of low calculation amount and communication cost, and is widely used in electronic payment, Internet of Things, etc. Existing signcryption schemes based on elliptic curve and bilinear pairing generally have the problem of low execution efficiency. Therefore, this paper proposes a certificateless signcryption scheme based on blockchain. The new scheme is implemented based on discrete logarithm puzzle and has the advantages of high execution efficiency. The new scheme also takes advantage of the non-tamperable modification and traceability of the blockchain to achieve non-repudiation. Security analysis shows that the proposed scheme has the characteristics of non-repudiation, confidentiality, and unforgeability. Performance analysis shows that the new scheme is more efficient in execution. Simulation experiments show that the introduction of blockchain has little effect on the overall performance of the system.

Key words: signcryption, certificateless; , blockchain discrete logarithm