Abstract Quantum private query (QPQ) enables users to extract desired entries from a database without decrypting its content, while simultaneously safeguarding both user query privacy and database security. In this paper, we propose a multi-user QPQ protocol based on Greenberger–Horne–Zeilinger (GHZ) states, which allows two distant users, Alice 1 and Alice 2 , to jointly query the same database entry. The protocol introduces a semi-trusted third party to prepare and distribute the GHZ states, and employs a bidirectional authentication mechanism to ensure the authenticity of the communicating entities. Security analysis demonstrates that the proposed protocol effectively resists both internal and external attacks and exhibits resilience against quantum computing attacks. Compared with existing QPQ schemes, the protocol significantly improves user privacy and database security while supporting multi-user collaborative queries.
Abstract Quantum private query (QPQ) enables users to extract desired entries from a database without decrypting its content, while simultaneously safeguarding both user query privacy and database security. In this paper, we propose a multi-user QPQ protocol based on Greenberger–Horne–Zeilinger (GHZ) states, which allows two distant users, Alice 1 and Alice 2 , to jointly query the same database entry. The protocol introduces a semi-trusted third party to prepare and distribute the GHZ states, and employs a bidirectional authentication mechanism to ensure the authenticity of the communicating entities. Security analysis demonstrates that the proposed protocol effectively resists both internal and external attacks and exhibits resilience against quantum computing attacks. Compared with existing QPQ schemes, the protocol significantly improves user privacy and database security while supporting multi-user collaborative queries.
With the development of quantum wireless networks, the practical application of quantum private query (QPQ) should conform to the features of quantum wireless networks to achieve any-to-any query, and QPQ requires a new query mechanism. We first propose a scheme for a network private query in a quantum wireless network with multiple third parties, in which any user can query any database with the assistance of the third parties, by measuring each of the distant nodes that initially share entanglement with each other. The required entanglement among these nodes is established by the third-party intermediate node equipped with GHZ generator using multi-qubit GHZ states. A bilayer network topology, as well as the corresponding private query protocol, ensures the rapid and secure private query. Under the protection of the multi-qubit GHZ state's quantum correlation, the privacy of Alice and Bob is protected from the third parties' fake entangled attack and external attack, and they cannot obtain the privacy of each other by taking quantum memory attack. The performance parameters of the proposed scheme are described based on the analysis of classical wireless communication cost and communication delay.
Abstract In order to protect the privacy of query user and database, some QKD-based quantum private query (QPQ) protocols were proposed. Unfortunately some of them cannot resist internal attack from database perfectly; some others can ensure better user privacy but require a reduction of database privacy. In this paper, a novel two-way QPQ protocol is proposed to ensure the privacy of both sides of communication. In our protocol, user makes initial quantum states and derives the key bit by comparing initial quantum state and outcome state returned from database by ctrl or shift mode instead of announcing two non-orthogonal qubits as others which may leak part secret information. In this way, not only the privacy of database be ensured but also user privacy is strengthened. Furthermore, our protocol can also realize the security of loss-tolerance, cheat-sensitive, and resisting JM attack etc.
Abstract A successful implementation of any secure communication protocols requires the identity authentication as a prerequisite. Quantum identity authentication (QIA) can ensure the unconditional security of identity code. In this paper, we propose a multi-party simultaneous quantum identity authentication (MSQIA) protocol based on the Greenberger-Horne-Zeilinger (GHZ) state. In the protocol, N certified users can directly send their identity codes to the authenticator Alice simultaneously through quantum channels without classical communication, which enables Alice to authenticate their identity at the same time. Our protocol only requires Alice to perform the single-photon measurement. In theory, this protocol is unconditionally secure and one pair of ( N + 1)-photon GHZ state can transmit N bits of identity codes. Our MSQIA protocol has application potential in the quantum communication field in the near future.
Secure multi-party extremum, as a significant offshoot of secure multi-party computation, has extensive applications in various domains, including healthcare, financial transactions, market analysis, sports events, etc. Nevertheless, most existing secure multi-party extremum protocols rely on computational hard problems and are thus vulnerable to quantum algorithms. This paper presents a quantum secure multi-party extremum protocol that is built upon the correlations of Greenberger–Horne–Zeilinger (GHZ) states. Within this protocol, multiple participants, with the aid of a semi-honest third party, can obtain the maximum and minimum values of their secret inputs. GHZ states act as the information carriers and are transmitted among the participants and the third party. Their unique correlations ensure the secure transmission of quantum particles. The analysis demonstrates that the proposed protocol is capable of not only warding off common external attacks but also resisting internal attacks launched by dishonest participants and the semi-honest third party. Moreover, the protocol boasts correctness and high scalability.
The rapid development of telemedicine technology has brought great convenience to people’s lives. Alongside generating great convenience, protecting patients’ privacy has become increasingly important. Therefore, to solve the above problems, this paper proposes a quantum privacy query protocol based on GHZ-like states. The protocol first utilizes existing diagnostic information for classification to encode symptom attributes. Then, the correlation after measurement using GHZ-like entangled states is utilized so that the querying party can only obtain a key message with the assistance of a third party. Through the above operation, the database cannot know the address of the message queried by the querying party, and the querying party is also unable to obtain more information. The protocol not only adds decoy factor detection but also adds the process of authentication while checking for illegal eavesdropping. It makes the protocol sufficiently resistant to joint attacks, participant attacks, and external system credit attacks. This database privacy query protocol ensures that the database service is more effective and its environment is more secure.
Abstract By introducing a semi-honest third party (TP), this paper proposes a novel quantum private comparison (QPC) protocol using ( n + 1)-qubit ( n ≥ 2) Greenberger-Horne-Zeilinger (GHZ) states as information carriers. The parameter n not only determines the number of qubits contained in a GHZ state, but also determines the probability that TP can successfully steal the participants’ data and the qubit efficiency. In the proposed protocol, any other quantum technologies (e.g., entanglement swapping and unitary operation) except necessary technologies such as preparing quantum states and quantum measurements are employed, which can reduce the need for quantum devices. The proposed protocol uses the keys generated by quantum key distribution and bit-flipping for privacy protection, and decoy photons for eavesdropping checking, making both external and internal attacks invalid. Specifically, for external attacks, several well-known attack means (e.g., the intercept-resend attack and the measurement-resend attack) are taken as examples to show that the attackers outside the protocol can not steal the participants’ data successfully, in which the security proof of the protocol against the entanglement-measurement attack is provided. For internal attacks, it is shown that TP cannot steal the participants’ data and the participants cannot steal each other’s data. It is also shown that the existing attack means against QPC protocols are invalid for our protocol.