Pairing-Free Certificateless Signature Scheme Based on SM2 Algorithm

Certificateless signature scheme can be applied to ensure data integrity, where the public key infrastructure cannot be not easily deployed while the identity-based cryptography is not suitable either because of the key-escrow problem. In many applications, large amount of resource-limited equipment are installed and there is the demand of reducing the computational burden. On the other hand, the Chinese national cryptographic standards (SM algorithms) have been widely adopted in both domestic and abroad. The SM algorithms are preferred and even compulsory, in particular with the key infrastructure systems. For certificateless schemes, the national standard have not been selected and published. Meanwhile, traditional constructions extended from identity-based schemes share the same underlying mathematical structure. For example, the SM9 algorithm require bilinear pairing operations and a certificateless scheme extended from it also requires comparatively heavy computations. In this paper, we study how to achieve pairing-free certificateless signature scheme and propose a concrete construction based on SM2 algorithm. The core idea of the construction is similar to the general transformation from traditional signature to identity-based signature by Bellare et al. and it does not resort to bilinear pairing.