Quantum public-key designated verifier signature

Based on the single-qubit rotations, a quantum public-key designated verifier signature (DVS) is proposed. In this scheme, a rotation vector is employed as the signatory’s secret key, and its corresponding quantum sequence is used as the public key. A quantum Diffie–Hellman key can be shared by the signatory and the designated verifier from their quantum public keys. The signatory encrypts the message string into some non-orthogonal particles and performs NOT operations on the quantum Diffie–Hellman key according to the message digest. After these steps, the quantum signature is generated. None but the designed partner can finish verifying of the received quantum signature. The proposed DVS has some other security properties such as source non-traceability and non-transferability. Its unforgeability can be guaranteed by the basic principle of the quantum mechanics. Furthermore, there is not any arbitrator in this DVS scheme. The verifier can finish verifying the signature without the help of any third party. Therefore, it is impossible for the arbitrator to become a bottleneck in the network. Our scheme is the first quantum DVS scheme based on asymmetric quantum public-key system.