Two Party Generation of SM9 Digital Signature

SM9 is an identity-based cryptography algorithm published by the State Cryptography Administration of China, which has great application value because of its high security and convenience. However when applied in an end device with no cryptographic hardware, the private key may suffer from potential leakage. When applied in a resource constrained device, the device is incapable of performing the complicated computation of the SM9 digital signature scheme. To address such problems, in this paper, three schemes of two party generation of SM9 digital signature are proposed. Comparing to traditional IBC schemes, the proposed schemes can ensure the security of user's private key by secret sharing between an end device and a dedicated cryptographic service system which runs in a computer or server, when signing a message with the private key is needed, the two devices will collaborate to generate the signature with their respective secret shares. The proposed schemes have promising prospect in various applications.