Arbitrated quantum signature protocol with boson sampling-based random unitary encryption

For signing quantum messages, the arbitrated quantum signature (AQS) has been widely investigated to date. However, most of the existing AQS protocols are susceptible to different aspects of disavowal and forgery attacks due to the use of quantum one time pad (QOTP) encryption featuring the encryption manner with qubit by qubit and the commutative property of Pauli operations. We develop an AQS protocol with boson sampling-based random unitary encryption. The unique encryption is used to encrypt the message copy (ciphertext) to produce the signature, which can circumvent the drawbacks of the QOTP encryption and stand against the signer Alice's disavowal and the verifier Bob's forgery attacks including existential forgery under known message attacks. The employment of a random array via the public board can prevent Bob's repudiation attacks on the receipt and the integrality of the signature. The quantum walk-based teleportation is applied to teleport the message copy from Alice to Bob, which can avoid preparing the essential entanglement resource beforehand. Security analyses and discussions show that our AQS protocol is with impossibility of disavowal from Alice and Bob and impossibility of forgery from anyone.