Multiparty Quantum Research Articles

Efficient multiparty quantum secret sharing based on a novel structure and single qubits

Quantum secret sharing (QSS) is a significant branch of quantum cryptography and can be widely used in various applications. Quantum secret sharing schemes can be developed by utilizing different features of quantum mechanics, and quantum secure direct communication (QSDC) is an effective way to achieve secret sharing using single qubits. The utilization of QSDC offers certain benefits, such as low cost, high security, and great potential for implementation with current technologies. However, the purpose of QSDC is different from that of QSS, which causes some vulnerabilities, such as dishonest participant attacks. We discover two critical factors that affect the security of traditional protocols. Firstly, they skip a few steps from the QSDC protocol to the QSS protocol. Secondly, the participants have different privileges. This can lead to participants with more privileges engaging in potential attack behavior. In light of these issues, this study proposes a new multiparty QSS scheme to address these vulnerabilities. The proposed protocol ensures the independence of each participant and grants them equal privileges. Analysis results demonstrate that it can defend against malicious attackers, retain the advantages of the QSDC protocol, and further reduce transmission costs. It achieves an excellent balance between security and performance.

Practical multi-party quantum homomorphic encryption

Quantum homomorphic encryption (QHE) is allowed to perform operations on encrypted data which is very useful for delegated quantum computing in quantum cloud environments. But most of current QHE schemes only consider the single-user and single-server model. To be more practical and suitable for quantum networks, multi-party QHE based on quantum voting is considered in this paper. Firstly, an improved quantum voting scheme is proposed to facilitate anonymous broadcast. Secondly, a multi-party QHE scheme is proposed based on the improved quantum voting method. The proposed QHE scheme becomes more practical and flexible due to the reduction of the cost of delegated quantum computation, which significantly contributes to broadening the applicability of QHE in quantum networks.

Efficient multiparty quantum private comparison protocol based on single photons and rotation encryption

Efficient multiparty quantum private comparison protocol based on single photons and rotation encryption

Multi-party quantum private information comparison based on nonlocal orthogonal product states

Multi-party quantum private information comparison based on nonlocal orthogonal product states

Multi-party simultaneous quantum identity authentication based on Greenberger-Horne-Zeilinger states

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.

Correction to: A Tree-type Multiparty Quantum Key Agreement Protocol Against Collusive Attacks

Correction to: A Tree-type Multiparty Quantum Key Agreement Protocol Against Collusive Attacks

Multiparty quantum contract signing

Quantum contract signing has the advantage of unconditional security compared with classical one. However, the prior works focus on two clients’ case. In this paper, we give a multiparty quantum contract signing protocol, which allows multiparty clients to sign an electronic contract simultaneously. The analysis shows that it not only satisfies the requirements for optimism and fairness but also can be realized with current technology.

Measurement-device-independent multi-party quantum key agreement

Quantum key agreement (QKA) is an important quantum cryptography primitive. In a QKA protocol, two or more untrusted parties can agree on an identical key in such a way that they equally influence the key and no subset can decide it alone. However, in practical QKA, the imperfections of the participant’s detectors can be exploited to compromise the security and fairness of QKA. To remove all the detector-side-channel loopholes, a measurement-device-independent multi-party QKA protocol is proposed. The protocol exploits the post-selected GHZ states to generate a secure agreement key between legitimate participants, while ensuring the fairness of key agreement. Our protocol provides a new clue for the design of practical QKA protocols.

Quantum broadcast and multicast with non-maximally channels

Broadcast and multicast protocols are two branches of multi-party quantum communication. Implementing these protocols based on partial entanglement is of great practical importance since maximally entangled channels are not robust due to noise applied by the surrounding environment. Previous research has used global operators (i.e. operators which are applied on the qubits owned by different parties), which contradicts the concept of multi-party communication protocols. In this research, broadcast protocol and multicast protocol with two receivers are proposed using partially entangled channels. Then the protocols are extended to the case with an arbitrary number of receivers. In the proposed protocol, Alice shares a two-qubit maximally entangled state with each receiver, therefore the whole channel is a partially entangled state. Then, the proposed protocol is modified to be secure against eavesdroppers. Also, the effects of phase damping, bit flip, and phase damping noise on the broadcast protocol are examined and compared.

Experimental quantum secret sharing based on phase encoding of coherent states

Quantum secret sharing (QSS) is one of the basic communication primitives in future quantum networks which addresses part of the basic cryptographic tasks of multiparty communication and computation. Nevertheless, it is a challenge to provide a practical QSS protocol with security against general attacks. A QSS protocol that balances security and practicality is still lacking. Here, we propose a QSS protocol with simple phase encoding of coherent states among three parties. Removing the requirement of impractical entangled resources and the need for phase randomization, our protocol can be implemented with accessible technology. We provide the finite-key analysis against coherent attacks and implement a proof-of-principle experiment to demonstrate our scheme's feasibility. Our scheme achieves a key rate of 85.3 bps under a 35 dB channel loss. Combined with security against general attacks and accessible technology, our protocol is a promising candidate for practical multiparty quantum communication networks.

Multi-party quantum key agreement with parameter-independent channels

Multi-party quantum key agreement with parameter-independent channels

Multi-party quantum private comparison of size relationship with two third parties based on d-dimensional Bell states

In this paper, we put forward a multi-party quantum private comparison (MQPC) protocol with two semi-honest third parties (TPs) by adopting -dimensional Bell states, which can judge the size relationship of private integers from more than two users within one execution of protocol. Each TP is permitted to misbehave on her own but cannot collude with others. In the proposed MQPC protocol, TPs are only required to apply -dimensional single-particle measurements rather than -dimensional Bell state measurements. There are no quantum entanglement swapping and unitary operations required in the proposed MQPC protocol. The security analysis validates that the proposed MQPC protocol can resist both the outside attacks and the participant attacks. The proposed MQPC protocol is adaptive for the case that users want to compare the size relationship of their private integers under the control of two supervisors. Furthermore, the proposed MQPC protocol can be used in the strange user environment, because there are not any communication and pre-shared key between each pair of users.

Experimental implementation of Hardy-like quantum pigeonhole paradoxes

We present the general Hardy-like quantum pigeonhole paradoxes for \textit{n}-particle states, and find that each of such paradoxes can be simply associated to an un-colorable solution of a specific vertex-coloring problem induced from the projected-coloring graph (a kind of unconventional graph). Besides, as a special kind of Hardy's paradox, several kinds of Hardy-like quantum pigeonhole paradoxes can even give rise to higher success probability in demonstrating the conflict between quantum mechanics and local or noncontextual realism than the previous Hardy's paradoxes. Moreover, not only multi-qubit states, but high-dimensional states can exhibit the paradoxes. In contrast to only one type of contradiction presented in the original quantum pigeonhole paradox, two kinds of three-qubit projected-coloring graph states as the minimal illustration are discussed in our work, and an optical experiment to verify such stronger paradox is performed. This quantum paradox provides innovative thoughts and methods in exploring new types of stronger multi-party quantum nonlocality and may have potential applications in multi-party untrusted communications and device-independent random number generation.

Security analysis of measurement-device-independent quantum conference key agreement with weak randomness

Quantum conference key agreement (QCKA) allows multiple users to distribute secret conference keys over long distances. Measurement-device-independent QCKA (MDI-QCKA) is an effective QCKA scheme, which closes all detection loopholes and greatly enhances QCKA’s security in practical application. However, an eavesdropper (Eve) may compromise the security of practical systems and acquire conference key information by taking advantage of the weak randomness from the imperfect quantum devices. In this article, we analyze the performance of the MDI-QCKA scheme based on the weak randomness model. Our simulation results show that even a small proportion of weak randomness may lead to a noticeable fluctuation in the conference key rate. For the case with finite-key size, we find that the weak randomness damages the performance of MDI-QCKA to different degrees according to the data size of total pulses transmitted. Furthermore, we infer that QCKA based on single-photon interference technology may perform better in resisting weak randomness vulnerabilities. Our work contributes to the practical security analysis of multiparty quantum communication and takes a further step in the development of quantum networks.

Secure multiparty quantum aggregating protocol

Secure multiparty quantum computation is an important and essential paradigm of quantum computing. All the existing aggregating protocols are $(n, n)$ threshold approaches, where $n$ represents the total number of players. If one player is dishonest, the aggregation protocols cannot aggregate efficiently. In this paper, we propose a $(t, n)$ threshold-based aggregating protocol, where $t$ represents the threshold number of players. This protocol uses Shamir's secret sharing, quantum state, SUM gate, quantum Fourier transform, blind matrix, and Pauli operator. This protocol can perform the aggregation securely and efficiently. In this protocol, we simulate this aggregating protocol using the IBM quantum processor to verify the correctness and feasibility.

An Efficient Quantum Secret Sharing Scheme Based on Restricted Threshold Access Structure

Quantum secret sharing is an important branch of quantum cryptography, and secure multi-party quantum key distribution protocols can be constructed using quantum secret sharing. In this paper, we construct a quantum secret sharing scheme built on a constrained (t, n ) threshold access structure, where n is the number of participants and t is the threshold number of participants and the distributor. Participants from two different sets perform the corresponding phase shift operations on two particles in the GHZ state passed to them, and then t-1 participants with the distributor can recover the key, where the participant recovering the key measures the particles received by himself and finally obtains the key through the collaboration of the distributors. Security analysis shows that this protocol can be resistant to direct measurement attacks, interception retransmission attacks, and entanglement measurement attacks. This protocol is more secure, flexible, and efficient compared with similar existing protocols, which can save more quantum resources.

Multiple-participant measurement-device-independent quantum secret sharing protocol based on entanglement swapping

Quantum secret sharing (QSS) is a multi-party quantum communication mode, which allows the dealer to split a key into several parts and send each part of a key to a participant. The participants can obtain the key only by cooperation. Entanglement swapping is a promising method to construct the entanglement channel. In the paper, we propose a multiple-participant measurement-device-independent QSS protocol based on entanglement swapping. All the measurement tasks are handed over to an untrusted measurement party, so that our protocol can resist all possible attacks from imperfect measurement devices. Our protocol requires the linear-optical Bell state analysis, which is easy to operate. Our protocol has application potential in the future quantum communication field.

Efficient Multi-party Quantum Key Agreement Protocol Based on New Bell State Encoding Mode

Efficient Multi-party Quantum Key Agreement Protocol Based on New Bell State Encoding Mode

A Tree-type Multiparty Quantum Key Agreement Protocol Against Collusive Attacks

A Tree-type Multiparty Quantum Key Agreement Protocol Against Collusive Attacks

Multiparty quantum private comparison based on quantum walks

Multiparty quantum private comparison based on quantum walks