Efficient Quantum Private Comparison Based on GHZ States

Abstract

Quantum private comparison (QPC) is a fundamental cryptographic protocol that allows two parties to compare the equality of their private inputs without revealing any information about those inputs to each other. In recent years, QPC protocols utilizing various quantum resources have been proposed. However, these QPC protocols have lower utilization of quantum resources and qubit efficiency. To address this issue, we propose an efficient QPC protocol based on GHZ states, which leverages the unique properties of GHZ states and rotation operations to achieve secure and efficient private comparison. The secret information is encoded in the rotation angles of rotation operations performed on the received quantum sequence transmitted along the circular mode. This results in the multiplexing of quantum resources and enhances the utilization of quantum resources. Our protocol does not require quantum key distribution (QKD) for sharing a secret key to ensure the security of the inputs, resulting in no consumption of quantum resources for key sharing. One GHZ state can be compared to three bits of classical information in each comparison, leading to qubit efficiency reaching 100%. Compared with the existing QPC protocol, our protocol does not require quantum resources for sharing a secret key. It also demonstrates enhanced performance in qubit efficiency and the utilization of quantum resources.

New Quantum Private Comparison Using Four-Particle Cluster State

“…In this protocol, secrets are divided into multiple groups, which improves efficiency by eliminating the need to compare all groups of information. Since then, different QPC protocols have been continuously proposed, aiming to determine the relationship between private and these studies mainly utilize various quantum states, including single photons [ 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 ], Bell states [ 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 ], entangled states [ 34 , 35 , 36 , 37 , 38 , 39 ], cluster states [ 40 , 41 , 42 , 43 , 44 , 45 ] and d-level quantum states [ 46 , 47 , 48 , 49 ] as quantum resources. They also employ different quantum technologies, such as entanglement swapping and unitary operations, as well as determine whether to distribute keys for sharing secret keys to accomplish the comparison.…”