This study presents the first semi-quantum private comparison protocol under an almost-dishonest third party. The proposed protocol allows two classical participants to compare their secret information without compromising it's privacy. The security analyses indicate that the protocol is free from several well-known attacks.
Abstract Based on Bell states, a new semi-quantum private comparison protocol is proposed that enables two classical users to securely compare the equality of their private information with the aid of a semi-honest third party. Different from the existing semi-quantum private comparison protocols, the two classical participants in the presented protocol do not need to measure and prepare any quantum state, which not only reduces the consumption of quantum devices, but also greatly improves the feasibility of the protocol. Performing different unitary operations on the received particles, classical users can securely compare their secret information. Besides, the devised protocol has higher qubit efficiency than the other similar counterparts, since participants can compare a two-bit privacy each time with one qubit. Meanwhile, after completing the comparison process, all Bell states could be reused since they still retain the corresponding entanglement property, which greatly facilitates the recycle of quantum resources. Security analyses indicate that the designed scheme is secure against external attack and internal attack. Moreover, the operations involved in our scheme are simulated on the IBM Quantum Experience to demonstrate the effectiveness and security of our scheme.
We propose a feasible and efficient dynamic multiparty quantum private comparison protocol that is fully secure against participant attacks. In the proposed scheme, two almost-dishonest third parties generate two random keys and send them to all participants. Every participant independently encrypts their private information with the encryption keys and sends it to the third parties. The third parties can analyze the equality of all or some participants' secrets without gaining access to the secret information. New participants can dynamically join the protocol without the need for any additional conditions in the protocol. We provide detailed correctness and security analysis of the proposed protocol. Our security analysis of the proposed protocol against both inside and outside attacks proves that attackers cannot extract any secret information.
Private comparison is the basis of many encryption technologies, and several related Quantum Private Comparison (QPC) protocols have been published in recent years. In these existing protocols, secret information is encoded by using conjugate coding or orthogonal states, and all users are quantum participants. In this paper, a novel semi-quantum private comparison scheme is proposed, which employs Bell entangled states as quantum resources. Two semi-quantum participants compare the equivalence of their private information with the help of a semi-honest third party (TP). Compared with the previous classical protocols, these two semi-quantum users can only make some particular action, such as to measure, prepare and reflect quantum qubits only in the classical basis {|0⟩,|1⟩} , and TP needs to perform Bell basis measurement on reflecting qubits to obtain the results of the comparison. Further, analysis results show that this scheme can avoid outside and participant attacks and its’ qubit efficiency is better than the other two protocols mentioned in the paper.
Abstract Based on d -dimensional multiparticle maximal entangled states, a novel multi-party private comparison protocol under semi-quantum condition is proposed. With the help of a semi-honest quantum third party, N classical participants can determine the size relationship of their privacies while keeping them private in the devised protocol. Compared with some similar protocols, the presented protocol performs better in terms of security and qubit efficiency. In addition, the effectiveness and the correctness of our protocol are verified with some examples and proofs. By the decoy particles and the pre-shared keys, the presented protocol can defend against the internal and the external attacks.
For two participants to compare the equality of their private information without revealing them, a new quantum private protocol with the help of semi-honest third party TP is proposed. Different from previous protocols, the four particle |Wf⟩ state and the |χ+⟩ state are utilized in this protocol as the carriers of quantum information and form the entanglement swapping as basic principle. The simple measurement of quantum states and exclusive-or operation are only required to conduct in this protocol. What’s more, this protocol can compare two bits of two participants’ private information in every comparison time. Meanwhile, it needs no unitary operation to fulfill this protocol. This protocol is feasible and efficient to execute through these aspects. In the end, the security of this protocol is analyzed at great length from two kinds of attacks including the outside attack and the participant attack. And the analysis result shows that this protocol can withstand various kinds of attacks and be secure to perform efficiently.