Quantum Signature Scheme Based On Cluster State

With the continuous development of computer technology,the computing power of machines has been greatly improved,and the traditional cryptosystem is facing constant challenges.At the same time,the propose of quantum computing and the proposition of a series of quantum algorithms make many cryptographic protocols break down in classical cryptography.With the advancement of information society,a large number of personal information and communication information have been stolen,user data have been leaked,and issues of data security have become particularly important.Classical cryptosystems mostly use asymmetric public-key cryptosystems.The security of public-key cryptosystems mostly comes from the difficulty of solving mathematical problems,which seems to be declining with the breakthroughs in computing power.Quantum cryptography,which guarantees the high security of encryption protocols through the unique physical properties of quantum particle,has become a hot research spot.At the same time,cluster states have been widely used in quantum cryptography due to their good entanglement properties.In this paper,two quantum signature protocols are designed for information security in quantum networks:1.Quantum multi-proxy blind signature scheme based on four-qubit cluster states.Quantum systems of four-qubit cluster states are more complex.Each quantum state has four entangled qubits,which is suitable for designing signature protocols with multiple functions.The protocol uses four-qubit cluster states to design a multi-proxy blind signature protocol,and incorporates quantum state into the signature.Under a series of quantum operations and quantum measurements,the function of signature and verification of messages can be realized.This scheme satisfies all the characteristics of a multi-proxy blind signature scheme.At the same time,the scheme uses quantum key distribution protocol,quantum one-time pad,quantum secure direct communication protocol,eavesdropping check and other quantum means to ensure the security of this signature scheme.2.Quantum homomorphic signature scheme based on four-qubit cluster states.Inspired by the first quantum homomorphic signature scheme proposed by Shang et al.,a quantum homomorphic signature scheme is designed in the dual-proxy scenario.Shang et al.'s quantum homomorphic signature scheme makes use of quantum entanglement swapping to realize homomorphism,while the four-particle cluster state itself has the entanglement relationship between the four quantum bits.So,the distribution of particles is more flexible and the signature homomorphism can be achieved without entanglement swapping.Quantum key distribution protocol and eavesdropping check are used in this protocol,which makes it difficult for the protocol to be attacked,and the security of signature is guaranteed.