Security Analysis And Improvement Of Arbitrated Quantum Signature Protocols

Quantum signature is a cryptographic primitive to provide data integrity,authentication and non-repudiation design for quantum information,which combines the basic idea of classical digital signature.Arbitrated quantum signature(AQS)is an important research branch of quantum signature.To analyze security of existing AQS protocols makes great sense to evaluate security,exploite security vulnerabilities and improve security of protocols.This paper analyzes security of some unanalyzed AQS protocols in the past six years,discovers the security problems,and then proposes some improved schemes to enchance security of AQS protocols.Specifically,it mainly has completed the following four aspects of work:(1)A type of improved AQS protocols based on QO TP algorithm are analyzed.From the perspective of the communicative unitary operators,a method to look for the general solutions of the communicative unitary operator is given,as a result,attackers could use the solutions to forge signatures;(2)For an AQS protocol based on D-QOTP algorithm,a selective forgery attack method is given,and the probability that the signer successfully denies the signature is also given.(3)For an AQS protocol based on the chained CNOT algorithm,with the special properties of a transformation from binary keys into permutations and the chained CNOT algorithm,a malicious receiver to forge signatures with probability 1/2.And the signer can also deny his signatures with probability 1/4.Three possible improved methods are presented to resist attacks:padding constants,multiple chained CNOT algorithm and circular chained CNOT algorithm;(4)The rotation operator and the permutation operator are first constructed and are used to design a multi-qubit-message-oriented AQS protocol.Then,the security the protocol is analyzed under all known attacks.The results show that the protocol can resist all known forgery attacks and the signer’s disawal attacks.