An Arbitrated Quantum Signature with Bell States

Entanglement is the main resource in quantum communication. The main aims of the arbitrated quantum signature (AQS) scheme are to present an application of the entanglement in cryptology and to prove the possibility of the quantum signature. More specifically, the main function of quantum entangled states in the existing AQS schemes is to assist the signatory to transfer quantum states to the receiver. However, teleportation and the Leung quantum one-time pad (L-QOTP) algorithm are not enough to design a secure AQS scheme. For example, Pauli operations commute or anticommute with each other, which makes the implementation of attacks easily from the aspects of forgery and disavowal. To conquer this shortcoming, we construct an improved AQS scheme using a new QOTP algorithm. This scheme has three advantages: it randomly uses the Hadamard operation in the new QOTP to resist attacks by using the anticommutativity of nontrivial Pauli operators and it preserves almost all merits in the existing AQS schemes; even in the process of handling disputes, no party has chance to change the message and its signature without being discovered; the receiver can verify the integrity of the signature and discover the disavow of the signatory even in the last step of verification.