An identity-verifiable quantum threshold group signature scheme based on three-particle GHZ states

Abstract

With the advancement of the new generation of information technology in recent years, quantum digital signatures have been widely concerned. Among them, quantum threshold group signatures have become a hot research field due to their advantages such as low cost and strong scalability. Therefore, in this paper, we propose an identity-verifiable quantum threshold group signature scheme based on three-particle GHZ states. The characteristics of the scheme are as follows. The signers can reconstruct the key K for signature’s generation and verification by using the Shamir threshold secret sharing scheme. A quantum signature is generated by performing controlled-not operations, von Neumann measurements, and quantum Fourier transform. When the signature is verified, only classical hash values need to be compared, without comparing quantum states. Identity verification is performed between participants by using hash functions. The efficiency of the scheme is improved by using super-dense coding. Security analysis shows that our scheme is unforgeable and undeniable.