Study on Secret Sharing for SM2 Digital Signature and Its Application

Secret sharing is commonly used to protect the user's private key. SM2 is an elliptic curve public-key cryptography algorithm released by China's State Cryptography Administration. For its unique digital signature operation, ordinary secret sharing schemes are not suitable for the case of the digital signature using the SM2 private key. To solve this problem, the product-based secret sharing scheme and the summation-based secret sharing scheme for the SM2 digital signature are proposed in this paper. The summation-based secret sharing scheme, in particular, contains ordinary secret sharing and threshold secret sharing. In addition, this work applies the above two schemes to the Android mobile terminal to protect a user's SM2 private key.