Design And Research Of Quantum Proxy Signature Scheme

The quantum proxy signature,which is one of the most important research topics in quantum digital signature,plays a key role in the authentication and data integrity protection.In recent years,some quantum proxy signature schemes based on controlled teleportation are proposed by Cao et al..The properties of quantum mechanics,genuine entangled quantum states,controlled quantum teleportation,quantum key distribution,quantum one-time pad and quantum measurement are directly applied to ensure the security in these schemes.For the convenience of studying,we have summarized a general model from the quantum proxy signature schemes.As far as we know,a signature scheme should satisfy the security requirements,such as verifiability,unforgeability,undeniability etc.However,the verifiability of the message is not satisfied and the receiver Bob can forge a valid signature in the model.Furthermore,it is vulnerable for the collusive attack in their quantum proxy multi-signature scheme.It can be seen that there exist some loopholes which have not been considered in the previous analysis.We will give a detailed attack strategy to reexamine these schemes.Moreover,we have presented some feasible improvements and proved the security of improved ideas to overcome these loopholes in this paper.On the basis of that,we design a new model of quantum proxy signature scheme based on genuine entangled N_j-qubit(3?N_j?7,N_j?N~*)state.From our security analysis,the receiver Bob cannot forge the signature and the signatory Alice cannot disavow it neither.i.e.The security requirements of quantum proxy signature scheme can be satisfied in our model.We hope that this model would be positive for the design of QPS schemes.