Identity-based forward homomorphic SM2 co-signature method and system

Abstract

The present application relates to the field of cryptography, more particularly to an identity-based forward homomorphic SM2 collaborative signature method and system. The method comprises the following steps: a key generation process: a client generates a client sub-private key D1, a server generates a server sub-private key D2 and a public key P, which are used to complete collaborative signature; a collaborative signature process: the client and the server perform collaborative signature based on the SM2 algorithm; after each collaborative signature is completed, the client re-computes and generates a client sub-private key for the next collaborative signature, taking the collaborative signature request time, the server collaborative signature response time and identity information as parameters. The present application changes the client sub-private key after completing a collaborative signature on both the client and the server side, which can protect the confidentiality and privacy of the data to be signed, and can also realize different client sub-private keys corresponding to each collaborative signature stage, thereby improving the security of digital signature.

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