Quantum Private Comparison Protocol Based on Multiple GHZ States in Cross-domain Environment

The limitation of traditional comparison protocols lies in the plaintext transmission of data or the sharing of encryption keys, which may lead to the risk of privacy disclosure. Compared with traditional comparison protocols, quantum private comparison (QPC) protocols utilize the characteristics of quantum computing and communication to provide higher security and privacy protection. Users in different domains often cannot communicate directly or find it difficult to choose the same trusted third party. Previous QPC protocols often had the same trusted or semi-honest third party and were unable to cope with private data comparison in cross-domain environments. We use product states of three-particle GHZ state and four-particle cluster state to realize QPC in cross-domain environment, and users only need to select the nodes they trust in their own domain. Then, we analyze the security of the protocol under various attacks, and show the security under channel node collusion attacks. Finally, we compare this protocol with other protocols to show that our protocol can be adapted to cross-domain environments.