Quantum Privacy Comparison with Ry Rotation Operation

This paper presents a novel quantum privacy comparison (QPC) protocol that employs Ry rotation operations to enable two participants to securely compare their binary secrets without disclosing the actual data to any party except for the comparison result. In this protocol, classical bits 0 and 1 are encoded as rotation angles 0 and π, respectively, using the Ry rotation operation. The participants apply these rotations to quantum sequences received from a semi-honest third party (TP) and return the encoded sequences to the TP. The TP then performs quantum measurements to determine the comparison result and announces it to the participants, ensuring fairness and privacy throughout the process. By leveraging the principles of quantum mechanics, the protocol is resistant to various quantum attack strategies, providing robust security against both external adversaries and insider threats. The protocol utilizes Bell states as quantum resources, Ry rotation operations for encoding classical information, and quantum measurements to derive the comparison result, making it experimentally feasible with current quantum technologies. Simulations conducted on a quantum platform validate the protocol’s practicality. Furthermore, each Bell state is used to compare one bit of binary information, achieving a qubit efficiency of 50%.