Cryptanalysis and improvement of a semi-quantum private comparison protocol based on Bell states

Semi-quantum private comparison (SQPC) allows two participants with limited quantum ability to securely compare the equality of their secrets help a semi-dishonest third party (TP). Recently, Jiang (Quantum Inf Process 19(6): 180, 2020) proposed SQPC protocol based on Bell states and claimed it is secure. In this paper, we present types attack Jiang’s protocol. first type attack, an outside eavesdropper can make accept wrong result. second malicious participant not only other incorrect result, but also learn secret honest participant. Neither possible be detected. addition, propose improved that resist these attack.