In the signature algorithm

once the private key of the signature is stolen

the adversary can forge the signature of the legal user arbitrarily

which will cause the rights of legal users to be infringed.In order to reduce the risk of signature private key leakage

a secure two-party SM2 digital signature algorithm is proposed in this paper. The private key of the signature is divided into two parts and each part of the private key is handed over to the different parties separately. The cryptographic techniques such as zero-knowledge proof

bit commitment and homomorphic encryption are used to ensure that only the legal users can generate the integrated SM2 signature.The integrated private key cannot be recovered individually. The security of the proposed scheme is proved under the universally composable security framework.Compared with the existing SM2 cooperative signature schemes

the proposed scheme has the advantages of fewer interactions and higher efficiency.