Quantum Gate-Based Quantum Private Comparison

Many existing protocols of quantum private comparison (QPC) are often made up of quantum part and classical part, because they employ quantum technology to provide security and use classical computation to perform the comparison. This could result in some lurking unfavourable effects such as insufficient security. To improve the QPC security, the paper presents a QPC protocol without the classical part, which uses Bell states as the quantum resource and substitutes the action of quantum gate for the classical computation. It needs no other complex quantum operations including quantum entanglement swapping technology. Except the phase of the eavesdropping check, quantum measurement isn’t required at one party either. The presented protocol is not only simple and efficient but also of better security. The analyses indicate its correctness so it could serve as an alternative way to implement QPC.