Semi-quantum private comparison protocol with three-particle G-like states

Semi-quantum protocol allows users with only a small amount of quantum capabilities to participate in quantum communication, which is conducive to the application of quantum communication network. In the paper, a semi-quantum private comparison (SQPC) protocol based on three-particle G-like states is put forward. The protocol allows two classical users to compare the equality of their secret information without disclosing the information content with the help of a quantum third party (TP). TP is almost-dishonest; it may be misbehaving, but it does not allow collusion with other participants. The security of the proposed protocol is analyzed, and the results show that the protocol can resist internal and external attacks. Moreover, even if the attacker successfully steals the quantum information transmitted between TP and users, she cannot get the secret information. Finally, compared with other SQPC protocol, the proposed protocol has more excellent qubit efficiency.