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Current protocols face limitations due to the small number and single form of transmitted qubits, as well as the complexity involved in preparing quantum channels. To address these limitations and develop a novel and practical protocol, we propose a new symmetric cyclic controlled quantum teleportation protocol, using nineteen-qubit entangled state as the quantum channel. Specifically, Alice, Bob and Charlie cyclically send arbitrary three-qubit states among themselves with the help of the controller David. The specialty of the proposed protocol is the utilization of multiple easy-to-prepare Bell-states and single-qubits within the quantum channel, which effectively minimizes resource consumption. Furthermore, we generalize the protocol with n+1(n≥3) parties by using (6n+1)-qubit entangled state as the quantum channel. This paper briefly analyzes the security of the protocol and compares them with the previous protocols in terms of efficiency. The results show that the present protocol is secure and more efficient. Our scheme has the potential to play a crucial role in facilitating secure quantum communication between quantum nodes in quantum networks. [ABSTRACT FROM AUTHOR]

Currently, quantum communication is gradually moving from theory to reality. Considering the practical application of quantum communication, more effective and feasible quantum communication schemes are needed. The feasibility of quantum communication schemes can be effectively verified through the three-dimensional reconstruction technology in quantum computers, namely, quantum state tomography. Therefore, this paper creatively proposes a scheme for separating arbitrary two-qubit quantum information using three-qubit entangled states and Bell states as quantum channels and uses IBM Experience platform and quantum state tomography technology for experimental verification. A corresponding quantum circuit is designed on the IBM Quantum Experience cloud platform for experimental simulation. Without loss of generality, we use the RawFeatureVector circuit and a random function of Qiskit to generate the two-qubit state in our scheme. And on this basis, entirely and comprehensively extracted massive data of quantum state information to calculate fidelity, proving that the scheme is safe and effective. Finally, to ensure the communication security, we have analyzed the security of the scheme. [ABSTRACT FROM AUTHOR]

The limitation of traditional comparison protocols lies in the plaintext transmission of data or the sharing of encryption keys, which may lead to the risk of privacy disclosure. Compared with traditional comparison protocols, quantum private comparison (QPC) protocols utilize the characteristics of quantum computing and communication to provide higher security and privacy protection. Users in different domains often cannot communicate directly or find it difficult to choose the same trusted third party. Previous QPC protocols often had the same trusted or semi-honest third party and were unable to cope with private data comparison in cross-domain environments. We use product states of three-particle GHZ state and four-particle cluster state to realize QPC in cross-domain environment, and users only need to select the nodes they trust in their own domain. Then, we analyze the security of the protocol under various attacks, and show the security under channel node collusion attacks. Finally, we compare this protocol with other protocols to show that our protocol can be adapted to cross-domain environments. [ABSTRACT FROM AUTHOR]

In response to the emerging security challenges brought about by advances in quantum technology, traditional key agreement methods are encountering vulnerabilities. To address this issue, We propose a semi-quantum key agreement (SQKA) protocol that utilizes four different forms of the W state, a particle state with strong interparticle entanglement. Classical parties are pre-specified to perform distinct operations on various forms of W states, but these operations are completely random to other parties or potential attackers. Based on the sequence of measurement results transmitted by the quantum square and the pre-defined coding rules, the classical party can infer the operation performed by the other party to achieve identity authentication, and then publish the private key to generate the final key. The analysis of the protocol shows that it can effectively resist common inside and outside attacks, and has the advantage of being more efficient. In summary, by adopting SQKA protocol, we achieve a secure, fair and efficient key negotiation process, providing a feasible solution for cooperation between quantum and classical parties. [ABSTRACT FROM AUTHOR]

Based on three-particle pure states, a new anonymous semi-quantum privacy comparison is proposed to deal with the threat of quantum computing power faced by users without complete quantum capabilities in the post-quantum era. In this scheme, quantum entanglement and quantum uncertainty principles are used to ensure third party security, measurement attack security and entanglement attack security. Compared with most semi-quantum privacy comparison schemes, it reduces the risk of TP evil and improves communication efficiency. Therefore, the scheme has stronger safety and higher efficiency. [ABSTRACT FROM AUTHOR]

Privacy-preserving geometric intersection (PGI) is an important issue in Secure multiparty computation (SMC). The existing quantum PGI protocols are mainly based on grid coding, which requires a lot of computational complexity. The phase-encoded query method which has been used in some Quantum SMC protocols is suitable to solve the decision problem, but it needs to apply high dimensional Oracle operators. In this paper, we use the principle of phase-encoded query to solve an important PGI problem, namely privacy-preserving two-party circle intersection. We study the implementation of Oracle operator in detail, and achieve polynomial computational complexity by decompsing it into quantum arithmetic operations. Performance analysis shows that our protocol is correct and efficient, and can protect the privacy of all participants against internal and external attacks. [ABSTRACT FROM AUTHOR]

Quantum teleportation is a hot topic of extensive research at present, and bidirectional quantum teleportation is one of the important research directions. In this paper, we propose a scheme to realize controlled bidirectional quantum teleportation by using a six-particle as the quantum channel. In this scheme, the communication parties Alice and Bob need to cooperate to send and receive unknown arbitrary particle states, which can’t achieve the purpose alone. During the transmission, Alice and Bob only need to perform simple Bell state measurement and single-particle measurement, and the measurement steps are few. Finally, the purpose can be achieved by performing some appropriate unitary transformations. We validate the scheme on the IBM Quantum Experiment platform and the feasibility by data. In terms of security, we discuss the method of ensuring communication security when this scheme is subjected to external and internal attacks. Finally, we compare it with other bidirectional quantum teleportation schemes, our scheme consumes fewer quantum resources and classical resources, operates fewer times, and has higher transmission efficiency, which fully highlights the advantages of this scheme. [ABSTRACT FROM AUTHOR]

Remote quantum state preparation is of great significance in quantum communication networks and long distance quantum information transmission. In this paper, a multi-hop remote single-qubit state preparation scheme is proposed for quantum networks. In each hop, Bell states are used as quantum channels and a quantum state is transmitted to a destination node through intermediate nodes. By analyzing one-hop and two-hop remote state preparation, we extend the scheme to n-hop remote state preparation, where logical algebra expressions are introduced to present final results. Our scheme achieves the total success probability of “1” and is independent of the types of Bell states and the number of intermediate nodes. [ABSTRACT FROM AUTHOR]

Quantum information splitting is one of the important applications of quantum entanglement. In this paper, we propose a scheme for information splitting of arbitrary five-qubit state using a four-qubit entangled state as the quantum channel. In the scheme, Alice performs a simple gate operation and single-qubit measurement on the qubit, and Bob can reconstruct the initial state by performing the appropriate unitary operation and introducing three auxiliary qubits based on Alice’s measurement results. We validate the scheme on the IBM Quantum Experience platform and also ensure the security of the scheme by introducing four quantum states. Finally, this scheme is compared with the other two schemes, and the results show that our scheme is sufficiently superior. [ABSTRACT FROM AUTHOR]

A communication protocol that uses generalized GHZ quantum states to achieve dense coding in a noisy network. In this protocol, we first discuss two noisy communication environment models (bit flipped channel and phase flipped channel), then, we introduce the generalized GHZ-type quantum state, they are three particles in an entangled state, and one of the particles is in the sender’s (Alice) hand, and the other two particles are in the receiver’s (Bob) hand. After the sender (Alice) performs a unitary operation on the particle in her hand, it is sent out through a noisy channel, and the receiver (Bob) performs error correction (Calderbank-Shor-Steane (CSS) codes), and then performs a decoding operation to achieve dense coding. [ABSTRACT FROM AUTHOR]

Quantum communication is a kind of communication mode which uses quantum physical characteristics to ensure the security of information transmission channel. It is widely concerned because it is different from the traditional cryptographic communication. Among them, quantum teleportation is the main research field and the key technology to achieve secure communication. In this scheme, four-qubit entangled state is used as quantum channel to transmit unknown seven-qubit entangled state. Firstly, Alice will deform the unknown seven-qubit entangled state. After transmission, Alice performs a series of operations on the particles she owns, and performs single-qubit measurement operation, and tells Bob the measurement results through the classical channel. After the measurement, Bob can reconstruct the unknown seven-qubit entangled state by sending the measurement results and the corresponding unitary operation, and with the help of auxiliary particles. We also carried out a security analysis to prove that the scheme is safe, and use the IBM platform for experimental verification, compared with the previous scheme, the scheme is more simple and efficient. [ABSTRACT FROM AUTHOR]

Based on single photons in both polarization and spatial-mode degrees of freedom, an efficient and novel semi-quantum deterministic secure quantum communication (SQDSQC) protocol is presented. In this protocol, quantum sender only adopts the single photon as initial quantum resource. Under the premise of introducing two unitary operations, the communicants perform eavesdropping check and encoding secret message separately according to the transformation characteristics of the degrees of freedom of single photon, which improves the communication efficiency. Compared with other semi-quantum protocols that only consider the single photon with one degree of freedom, our protocol possesses a higher information transmission capability, because each single photon can carry two bits of secret message in a communication process. In addition, the single-photon measurement involved in the proposed protocol can reduce the complexity of the communication process. Eventually, the security analysis of this protocol shows that it can defend many types of attacks, such as the Trojan horse attack, the intercept-resend attack, the measure-resend attack, the entangle-measure attack, the DoS attack and other attacks. [ABSTRACT FROM AUTHOR]

A new two-party semi-quantum key agreement protocol is proposed with the four-particle χ-type entanglement states. In this protocol, the shared secret key is generated by using Bell measurement, Z-basis measurement, sequence replacement operations and unitary operations. The one-way semi-quantum key agreement protocol can resist the Trojan horse attack naturally and both participant attack and external one. Compared with other similar two-party quantum key agreement protocols, the presented protocol is relatively efficient since the random collapse of quantum entanglement states reduces the requirement on quantum operations, without involving the four-qubit joint measurements. [ABSTRACT FROM AUTHOR]

Quantum secure direct communication has significant theoretical and application value, which can safely transmit secret information without pre-sharing keys between legitimate users. Aiming at the problems of uncontrollable communication capacity and complex communication process of certain quantum secure direct communication protocols, we propose a three-party quantum secure direct communication (3P-QSDC) protocol with hyperentanglement under polarization and two spatial longitudinal momentum degrees of freedom (DOFs). The secret information of each legitimate user is encoded by using corresponding unitary operations in three degrees of freedom. Compared with previous 3P-QSDC protocols, our protocol has higher information capacity and can reasonably allocate resources to realize adaptive mutual communication of information capacity among three parties. Additionally, the overall analysis indicates that by inserting decoy photons for eavesdropping detection, the proposed protocol has better security, resisting multiple external attacks such as measure-resend and intercept-resend attacks. Our protocol is expected to realize applications with different data transmission capabilities between multiple parties in the future. [ABSTRACT FROM AUTHOR]

In this work we introduce a three-party quantum conference where the involved parties initially hold asymmetric quantum information which are finally shared amongst themselves by the execution of a quantum communication protocol. The three conferencing parties along with a controller are connected amongst themselves through a multipartite quantum entanglement which is used as quantum resource in the protocol. The role of the controller is confined to a final action without which the conference can not be performed. The present work is an instance of applications of multipartite entangled resources in communication problems. [ABSTRACT FROM AUTHOR]

Quantum private comparison (QPC) can tell us whether two users' private data are equal or not by quantum technology without disclosing privacy to each other. There are many QPC protocols with diverse procedures and a wide variety of quantum resources. If two forms of quantum states or above are used in a QPC protocol, there will be a need of multiple devices or methods to generate these quantum states, which could bring about some lurking unfavourable effects such as inefficiency and high costs in application. In order to improve the QPC efficiency and reduce costs, a design principle to develop QPC protocols is put forward as a reference in this paper. Also, to take Bell states for example, a QPC protocol with a single Bell state as quantum resource is presented. The protocol is not only simple yet efficient and easy to apply but also of low costs. The analyses show its correctness so it could behave as an alternative way to exercise QPC. [ABSTRACT FROM AUTHOR]

Combining the ideas of quantum state sharing and multi-party quantum remote control, a novel four-participant quantum rotation operation sharing protocol was proposed, which utilizes pre-shared entanglement and local operations. Concretely, using 4-qubit entanglement of Greenberger-Home-Zeilinger (GHZ) type state as quantum channel, the two senders of the protocol can remotely and independently implement various rotation operations on the target state of any site, which requires mutual cooperation between two agents. Moreover, by utilizing (M + N)-qubit GHZ type state as the entanglement channel, the above four-participant situation can be easily generalized to the scenario with M senders and N agents. [ABSTRACT FROM AUTHOR]

In this paper we propose two verifiable threshold quantum secret sharing protocols with d-dimensional GHZ state. In the proposed protocol, the dealer Alice firstly divides all participants into two groups to achieve the two-line transmission. Then she randomly generates a three-qudit GHZ state, inserts the first two particles into two detecting photon sequences and sends them to participants in each group. In the distribution phase, each participant calculates and sends his commitment values to Alice by quantum secure direct communication. Furthermore, each participant performs a unitary operation on these received particles and sends them to the next participant using the decoy-photon technique. In the verification phase, Alice can perform two rounds of verification and test all participants' honesty. In addition, we demonstrate our protocol to be secure against both eavesdropping and dishonest participants and compare our scheme with the existing schemes. [ABSTRACT FROM AUTHOR]

In this paper, a quantum sealed-bid protocol based on semi-quantum bidders is proposed. The protocol uses Bell states to encrypt message and realizes the process that bidders can directly transmit bidding information to the auction center safely. Its essence is a semi-quantum secure direct communication protocol using Bell states. Unlike most similar protocols, our scheme eliminates the trusted third-party Trent and sets the auction center Charlie as completely honest. Considering that the auction involves human activities, too many quantum servers are not only costly, but also unrealistic. Therefore, we set the bidders as semi-quantum users and implement the Vickrey auction. In addition, the security analysis shows that our scheme has high security and is completely feasible. [ABSTRACT FROM AUTHOR]

In this paper, inspired by Wang et al.'s deterministic secure quantum communication (DSQC) scheme (Commun. Theor. Phys. 60 (2013) 397–404), a novel quantum dialogue (QD) scheme is put forward also by using Bell states and single photons as quantum resource. The proposed scheme can effectively overcome the active attacks launched by an outside attacker, such the intercept-resend attack, the measure-resend attack, the entangle-measure attack, etc. The information-theoretical efficiency of the proposed scheme is as high as 66.67%. [ABSTRACT FROM AUTHOR]

Then Alice sends HT ht to David. Then Bob decrypts HT ht to get HT ht . In the quantum scheme, Bob sends HT ht to Charlie if a dispute happens. Here, HT ht is his signature. [Extracted from the article]

Distributed quantum system is a well-known method to overcome the problems of designing and manufacturing large quantum systems to achieve higher processing power in the world of quantum processing. In distributed quantum computing, a number of limited-capacity quantum circuits communicating with each other through communication channels operate as a large quantum circuit. The most essential step in designing a distributed quantum system is to optimize the communication between the components to reduce the overhead cost of communications. In this study, based on the commuting of quantum gates, an efficient method is proposed to reduce the number of teleportations required to perform distributed quantum circuits (DQCs). The results obtained from the evaluation of our method on benchmark circuits indicate an impressive decrease in the number of teleportations and a significant reduction in the execution time compared to the present methods. [ABSTRACT FROM AUTHOR]

In the present work, a novel approach was proposed to optimize the teleportation cost in Distributed Quantum Circuits (DQCs) by applying a new approach. To overcome the difficulty with keeping a large number of qubits next to each other, DQCs, as a well-known solution, have always been employed. In a distributed quantum system, qubits are transferred from a subsystem to another subsystem by a quantum protocol such as teleportation. First, we proposed a heuristic approach through which we could replace the equivalent circuits in the initial quantum circuit. Then, we used a genetic algorithm to partition the placement of qubits so that the number of teleportations could be optimized for the communications of a DQC. Finally, results showed that the proposed approach could impressively work. [ABSTRACT FROM AUTHOR]

The main defects of the existing quantum secret sharing schemes are as follows: (1) The identity of the secret sender cannot be confirmed. Receivers of shared secret information may be vulnerable to Trojan attacks; (2) If a malicious attacker Eve impersonates the identity of the receiver, she can finally obtain all the information of the secret that Alice shared; (3) In the process of secret recovery, it is necessary to transmit qubits among all participants involved in secret recovery. Sometimes, the same particle needs to be operated on by all participants to achieve secret sharing, which increases the possibility of eavesdropping and also increases the probability of errors. In this work, we proposed a quantum secret sharing scheme with authentication, the receiver performs corresponding operations on qubits of Greenberger-Horne-Zeilinger(GHZ) state based on the key string calculated by the shared identity number and random Error Correction Code(ECC), the secret sender can calculate the corresponding measurement basis(MB) through the information she has, and then inform the measurement party. This process realizes the mutual authentication between the sender and the receiver. It can protect against identity impersonation attacks, through the ECC verification, it also can resist intercept-resend attacks. [ABSTRACT FROM AUTHOR]

With the rapid development of computer-related technology, how to realize privacy query between both parties becomes very important. In this paper, we propose a quantum privacy query protocol based on W state, compared with the GHZ state, the W state is more robust and easier to prepare, the quantum circuit for preparing W state is also given. The protocol makes use of the correlation after entangled state measurement, and enables the querying party to obtain only one secret key information with the assistance of a third party, thus compared with existing schemes, this scheme eliminates the need for classic post-processing operations and can resist joint measurement attacks. In addition, the proposed protocol has two security checks, which can well resist ancilla particle attacks and entanglement measurement attacks by third parties and external intruders participating in the protocol. Therefore, the proposal of this protocol is very necessary. [ABSTRACT FROM AUTHOR]

Quantum teleportation is an important method for transmitting quantum states between two quantum communication nodes. In this paper, we propose a low-latency quantum communication scheme based on Greenberger-Horne-Zeilinger (GHZ) state. To implement two-qubit transmission, the source and all intermediate nodes perform quantum measurements simultaneously and the measurement results are transmitted to the destination node through classical channel independently. The destination node performs appropriate unitary operation on its particles to recover the original two-qubit state based on received measurement results. Our scheme effectively reduces the end-to-end quantum communication delay. [ABSTRACT FROM AUTHOR]

In this paper, we present a quantum key agreement (QKA) protocol with non-maximally entangled four-qubit cluster states. In our scheme, each participant carries out two unitary operations on the same photons of each cluster state according to its own encryption key. Then, all participants generate identical four-bit shared keys by positive operator-valued measurement (POVM). Since POVM is probabilistic, it is necessary to prepare a longer raw key, and we only select sub-keys in public locations of qubit sequences where all participants succeed in POVMs as the final negotiation key. The advantage of our protocol is that non-maximally entangled cluster states are firstly utilized as the carrier of quantum information in quantum key agreement protocol. It also ensures that the shared key is decided by all participants, not by someone alone. In addition, it is proved that our protocol can resist external attacks and participant attacks, which demonstrates a high security. [ABSTRACT FROM AUTHOR]

Recently, people are paying more and more attention to privacy-enhanced computing, mostly because of the threat of network information leakage. In order to ensure the security of data in network communication, we have designed privacy-enhanced multi-user quantum private data query using partial quantum homomorphic encryption to facilitate the protection of the personal privacy of the database and users. Many QPQ protocols are based on QKD theory and lack the identity authentication of users. The protocols are vulnerable to external eavesdropping attacks. The identity authentication process of this scheme confirms the real identity of the user and avoids external eavesdropping attacks to a certain extent. The scheme allows the use of universal quantum circuits to perform quantum transformation on the user's arbitrarily encrypted input data, which improves the accuracy of the data query process. In addition, the scheme applies partial quantum homomorphic encryption theory to multi-user quantum private data query, which can realize the function of n users querying data at the same time. We have implemented a security analysis on the scheme and compared with other QPQ protocols, we found that this scheme is safe and effective. [ABSTRACT FROM AUTHOR]

We propose a new scheme to strengthen the performance of the discrete-modulated continuous-variable measurement-device-independent quantum key distribution (DM-CV-MDI-QKD) protocol by introducing a quantum scissors (QS) operation to Bob's side. According to the equivalent one-way scheme of the protocol, we further investigate the success probability of the QS operation, and analyze the security of the DM-CV-MDI-QKD equipped with this operation in the asymptotic case. Simulation results show that the QS operation can indeed effectively improve the performance of the existing protocol, and compared with the scheme without QS operation, our proposed scheme has a higher secret key rate and a longer secure transmission distance. [ABSTRACT FROM AUTHOR]

In this paper, we propose a scheme of quantum operation teleportation (QOT) utilizing local operations and five-qubit entangled state to achieve mutual authentication and key agreement for two clients in different realms. On the one hand, the scheme not only has the characteristics of the arbitrariness of the relevant operation, the certainty of sharing success and the constancy of entangled resources, but also realizes the mutual authentication among the four parties, ensuring the reliability and security of the task. On the other hand, considering the complexity of the operation, we complete the current QOT task as a whole, so the operation difficulty is low and relatively simple. In summary, our analysis is completely feasible under the existing technical conditions and this proposed scheme has practical significance. [ABSTRACT FROM AUTHOR]

A controlled deterministic secure semi-quantum communication protocol based on GHZ-like states is proposed for improving the security of semi-quantum communication. The protocol includes three participants, one is Alice with quantum capabilities who can prepare GHZ-like states to provide a secure and controllable quantum channel, and the remaining are Bob and controller Charlie who have only classical abilities. During the communication process, Bob compresses the secret message to obtain a binary string with Huffman compression coding technology, and then performs encoding and encryption operations to improve confidentiality. Furthermore, the analysis results demonstrate that the proposed CDSSQC protocol can effectively resist Trojan horse attacks, intercept-resend attack, double CNOT attack and other attacks. [ABSTRACT FROM AUTHOR]

Quantum nonlocality plays an important role in quantum information and quantum communication. Different from local realism, nonlocality means that multiple bodies can affect each other instantaneously regardless of the distance. The more the systems, the more complex the nonlocal nature. As a useful quantum information resource, nonlocality also has the characteristic of degeneration, that is, nonlocality ability will inevitably be reduced by external influences. Based on such characteristics, through some local operators or distillation protocols, make the correlation stronger is of great significance. In this paper, we propose a distillation protocol which can distill nonlocality in n-Gteenberg-Horne-Zeilinger (n-GHZ) box and we show the effective of this protocol. Besides, we will also give a general construct of n-bit box distillation protocol, which means that it is effective even we use different nonlocality measure formula or other n-bit box. [ABSTRACT FROM AUTHOR]

We present a protocol for controlled cyclic remote preparation of an arbitrary single-qudit state via a seven-qudit cluster state. In the protocol, Alice can help the remote agent Bob prepare an arbitrary single-qudit state, Bob can help the agent Charlie prepare an arbitrary single-qudit state and at the same time Charlie can help Alice prepare an arbitrary single-qudit state under the controller David's control. Alice, Bob and Charlie first perform positive operator-valued measurement (POVM) on their entangled particles according to the information of the prepared state, then perform generalized X-basis measurement. The controller performs generalized X-basis measurement on his entangled particle. The arbitrary single-qudit states can be cyclic remote prepared under the controller's control. The protocol is more convenient in application since it only requires single-particle measurement and single-particle unitary operations for controlled cyclic remote preparation of the single-qudit states. [ABSTRACT FROM AUTHOR]

Quantum state sharing (QSS) plays significant role in transmitting quantum secret information. However, in practical quantum communication situation, quantum information transmission is inevitably affected by the noisy environment. In this paper, we investigate the influence of correlated noise on QSS. We first present a QSS scheme and construct a noisy QSS. Subsequently, the fidelity of the scheme is discussed. It is found that there are different behaviors of fidelity in Markovian regime and non-Markovian regime. Furthermore, a method is proposed to steer the performance of the noisy QSS scheme with filtering operator. [ABSTRACT FROM AUTHOR]

The number of qubits involved in a quantum system increases as the quantum computation is being progressed. Restrictions in monolithic quantum computing systems capacity can be overcome by utilizing the distributed circuits. For the implementation of global gates (two-quibt gates whose control and target qubits belong to different partitions), it is required that one qubit be teleported to the other partition. Teleportation is a costly protocol (it requires sharing entanglement between two partitions), and the number of teleportations required for implement a given distributed circuit is called teleportation cost. It is desirable to distribute a quantum computation in such a way that the teleportation cost is reduced. A previous work has presented a way to optimize distributed quantum circuits in terms of teleportation cost for a predetermined partitioning. In this research, Shore circuit to factor number 15 synthesized in the single-qubit and CNOT gates is provided. After that, the circuit partitioning with the minimal cost of communication is presented. [ABSTRACT FROM AUTHOR]

A quantum secure multiparty summation protocol is constructed based on the phase shifting operation of d-level quantum system which utilizes the integer-by-integer technique to calculate the modulo d addition. The semi-honest third party prepares d-level two-particle entangled states and transmits the particle sequence composed by all second particles to n secrecy owners. n secrecy owners in turn encode their respective secrecy on this particle sequence through the phase shifting operation. Detailed security analysis turns out that both the outside attack and the participant attack are ineffective towards this protocol. Compared with the quantum secure summation protocols with bit-by-bit calculations, its calculation efficiency is higher; and compared with the protocols with smaller modulo, its applications are more extensive. Especailly, this protocol has extensive applications in the realm of quantum secure multiparty computation, such as quantum multiparty private comparison, quantum multiparty anonymous ranking, quantum multiparty anonymous voting, quantum multiparty key agreement, etc. [ABSTRACT FROM AUTHOR]

Quantum communication in general helps deter potential eavesdropping in the course of transmission of bits to enable secure communication between two or more parties. In this paper, we propose a novel quasi-deterministic secure quantum communication scheme using non-maximally entangled states. The proposed scheme follows a simple procedure, and cases where the entanglement required can be significantly reduced to carry out the protocol successfully are discussed. Long sequences or the whole sequence of data can be sent after error checking for a potential eavesdropper. The maximum qubit efficiency of the proposed protocol is found to be 33.333%. [ABSTRACT FROM AUTHOR]

Recently, Tian et al. proposed a multi-user quantum private query protocol. The protocol realizes the function of n users querying the database at the same time, which can well protect the privacy of users and databases, and has high efficiency of implementation. Unfortunately, it has security vulnerability in the process of sending quantum sequences. Based on this vulnerability, we propose a man-in-the-middle attack on multi-user quantum private query protocol. Firstly, this paper reviews the multi-user quantum private query protocol. Secondly, the implementation steps of multi-user private query protocol are reviewed concisely. Finally, we pointed that in the protocol, Eve, the eavesdropper, can pretend to be Bob and the identity of the user to obtain the key of query data and steal the database information without being discovered. Through analysis, we find that man in the middle attack is feasible. [ABSTRACT FROM AUTHOR]

Luo and Hwang [Quantum Inf. Process (2016) 15:947–958] proposed the authenticated semi-quantum direct communication protocols for a quantum participant to be able to transmit secret messages to a classical participant without employing an authenticated classical channel. However, this study indicates that there is an information leakage problem in Luo and Hwang's measure-resend protocol. The information leakage problem might allow an attacker to use an intercept-resend attack to obtain partial secret messages. Finally, an improved method is proposed to overcome the information leakage problem. [ABSTRACT FROM AUTHOR]

In this paper we design a deterministic controllable quantum communication protocol for remotely preparing three-qubit GHZ-type and four-qubit W-type entangled states at two different locations at the same time. Two parties (the preparers) along with a third party (the controller) are connected through a proper multipartite entangled resource. The states to be prepared are not physically available, only the classical information of each state is known by a party who intends to remotely prepare it at the end of the other party under the same control of a third party. Concretely, it is a multi-tasking protocol in which remote preparations of the two inequivalent states are accomplished not only simultaneously but also controllably through execution of a single protocol by utilizing an eleven-qubit entangled state as shared quantum resource. We also propose a generation process of the multipartite quantum resource used. [ABSTRACT FROM AUTHOR]

Photonic hyperentanglement, which involves photons simultaneously entangled in more than one degree of freedom (DOF), has many important applications in quantum information processing, especially in high-capacity quantum communications. Interestingly, single-photon qubits encoded in the time-bin DOF are robust for long-distance transmissions in noisy channels. In this paper, we present a hyperentangled-Bell-state generation (HBSG) scheme for preparing two-photon six-qubit states which are simultaneously entangled in the polarization, spatial-mode, and time-bin DOFs. Compared with previous HBSG schemes, we construct an error-detected circuit unit with a quantum-dot (QD) spin in a double-sided optical microcavity, with which errors due to imperfect interactions between photons and QD systems can be easily detected, so that the error-detected circuit unit can relax the experimental requirement and improve the fidelity of our scheme largely. Meanwhile, our scheme is used to prepare two-photon hyperentangled states in polarization-spatial-time three DOFs, which is significant for faithful entanglement distribution and quantum repeater. These features make our scheme more feasible and useful in high-capacity and long-distance quantum communications with hyperentanglement. [ABSTRACT FROM AUTHOR]

In this paper we analyse the performance of quantum low-density parity-check (LDPC) codes over quantum memory channels for correcting correlated errors, where the quantum LDPC codes we use are the hypergraph product quantum LDPC codes. We generalize the classical Gilbert-Elliot markovian memory channel to the quantum Gilbert-Elliot channel and use it to model the memory effect in quantum memory channels. The simulation results show the memory effects in quantum GE channels has a bad effect to the performance of hypergraph product quantum LDPC codes. Then we propose a concatenation scheme by serially concatenating two hypergraph product quantum LDPC codes and it is shown that the serial concatenation scheme can improve the performance of hypergraph product quantum LDPC codes and lower down the error floor over quantum GE channels. [ABSTRACT FROM AUTHOR]

The main objective of this paper is to improve the communication cost in distributed quantum circuits. To this end, we present a method for generating distributed quantum circuits from monolithic quantum circuits in such a way that communication between partitions of a distributed quantum circuit is minimized. Thus, the communication between distributed components is performed at a lower cost. Compared to the existing works, our approach can effectively map a quantum circuit into an appropriate number of distributed components. Since teleportation is usually the protocol used to connect components in a distributed quantum circuit, our approach ultimately reduces the number of teleportations. The results of applying our approach to the benchmark quantum circuits determine its effectiveness and show that partitioning is a necessary step in constructing distributed quantum circuit. [ABSTRACT FROM AUTHOR]

Quantum secure communication network is in the stage of rapid construction. As classical networks, we researchers also need to develop different practical quantum protocols for different application scenarios in quantum communication network. However, complex quantum operations and expensive quantum resource preparation seriously hinder the practical development of quantum communication networks. A variety of quantum signature protocols play an important role in quantum communications; however, these protocols also face the same problems described above. In this paper, we propose a semi-quantum proxy signature scheme with quantum walk-based teleportation to solve these problems. Proxy signer TP as the quantum participant and original signer Alice is the classical participant. We introduce quantum walk teleportation to generate quantum entanglement resource naturally in signature phase, which seems more in line with the reality of quantum communication networks. Security analysis show that this scheme meets all the security requirement of quantum proxy signature protocol, and the qubit efficiency analysis also proves this protocol has better practical value. [ABSTRACT FROM AUTHOR]

We propose a quantum cryptography based on an algorithm for determining a function using continuous-variable entangled states. The security of our cryptography is based on the Ekert 1991 protocol, which uses an entangled state. Eavesdropping destroys the entangled state. Alice selects a secret function from the very large number of possible function types. Bob's aim is to determine the selected function (a key) without an eavesdropper learning it. In order for both Alice and Bob to be able to select the same function classically, in the worst case Bob requires a very large number of queries to Alice. In the quantum case however, Bob requires just a single query. By measuring the single entangled state, which is sent to him by Alice, Bob can obtain the function that Alice has selected. This quantum key distribution method is faster than the very large number of classical queries that would be required in the classical case. [ABSTRACT FROM AUTHOR]

In this paper, a multi-party quantum private comparison (MQPC) protocol is proposed based on the qudit shifting operation. The semi-honest third party (TP) prepares the initial particles and sends them to the first user. Then, each of n users encodes his private integers on the travelling particles with the qudit shifting operations and transmits them to the next user. Finally, the travelling particles are transmitted back to TP. The equality of the private integers from n users can be determined within one time execution of the protocol. It is verified that the proposed protocol is secure against both the outside attack and the participant attack. One user cannot obtain other users' private integers except for the case that their private integers are same. TP cannot know the private integers from n users except their comparison result. [ABSTRACT FROM AUTHOR]

We propose quantum cryptography based on an algorithm of determining a function using qudit systems. The security of our cryptography is based on the Ekert 1991 protocol, that is, we use an entangled state. An eavesdropper must destroy the entangled state. Consider one of many functions. Alice selects a secret function. Bob's aim is of determining the selected function (a key) without the eavesdropper knows it. To select the same function, in classical case, at the worst case, Bob needs many queries to Alice. In quantum case, Bob needs just a query. By measuring the single entangled state, which is sent by Alice, Bob can obtain the selected function. This is faster than classical cryptography. [ABSTRACT FROM AUTHOR]

With the rise of the Internet plus blockchain, quantum secure communication has become a hot topic of interdisciplinary research. Secret sharing is the key technology to realize blockchain. In this paper, the Hermite interpolation polynomial combined with the idea of homomorphic cryptography is used to construct a multi-secret sharing model based on quantum graph theory. This paper relies on the theory of quantum theory to have mature theoretical and experimental foundations in quantum preparation, storage transmission, and measurement feasibility and overcomes the existing program feasibility problems and potential security problems with classical cryptography. This model is outsourced, verifiable, and extensible and has a high information rate. It can effectively resist external interception, replay, entanglement, tampering attacks and internal forgery, impersonation, deception, and collusion attacks. This paper has carried on a detailed analysis of the model. [ABSTRACT FROM AUTHOR]

As we know, if a quantum communication protocol has the information leakage problem, it is an insecure protocol, so we should carefully design the protocol to avoid the information leakage problem. Unfortunately, we find this problem exists in the "secure quantum dialogue (QD) protocol based on four-qubit cluster state". It is found that half of the exchanged information leaks out. To make up this problem, two ways to improve it is given. It shows that the improved QD protocols successfully avoid the information leakage problem. Especially, the further improved QD protocol only needs the single particle measurement instead of Bell-basis measurement and doesn't need any unitary operation to be performed. In addition, the communication efficiency is improved to 1.33 times of the original QD protocol. [ABSTRACT FROM AUTHOR]

We propose the unidimensional continuous-variable quantum key distribution(UDCVQKD) protocol based on the basis-encoding of Gaussian modulated coherent states. the UDCVQKD protocol disregards the necessity in one of the quadrature modulations in coherent states. On that basis, we propose our scheme by encoding the secret keys on the either randomly selected measurement bases: the phase quadrature (X) or the amplitude quadrature (P), in order to slightly weaken the effects of reconciliation efficiency and channel excess noise compare to the present UCVQKD protocol. The new protocol with a view to simplify the precedent unidimensional protocols in the decoding procedure, meanwhile ensure the security of the quantum communication. [ABSTRACT FROM AUTHOR]