关键词: 格, 基于身份密码学, 可追踪环签名, 小整数解问题

Abstract:

The ring signature is a special digital signature that can provide unconditional anonymous protection for signers,and a traceable ring signature is a variant of the ring signature,which aims to prevent signers from abusing the anonymity of the ring signature,that is,the anonymity provided by the traceable ring signature for signers is not unconditional,which will lead to the identity of signers being disclosed under certain behaviors of the signer.The traceable ring signature plays an important role in an electronic voting system and an electronic cash system.Aiming at the present situation that traceable ring signature schemes on lattice are based on the PKI system and have a complex burden of digital certificate management,this paper combines identity-based cryptography with the traceable ring signature on lattice and proposes the first identity-based traceable ring signature scheme on the lattice.Different from the previous traceable ring signature schemes,the proposed scheme is constructed according to the framework of Baum et al.’s linkable ring signature scheme on lattice and based on the techniques of preimage sampling and reject sampling,etc.,thus avoiding the use of cumbersome zero-knowledge proofs.Under the random oracle model,it is proved that the proposed scheme can meet the tag-linkability,anonymity and exculpability,and that the security can be reduced to SIS and ISIS problems.In addition,compared with the related schemes,the proposed scheme also has some advantages in time overhead and storage overhead.

Key words: lattice, identity-based cryptography, traceable ring signature, small integer solution problem