Decoy Photons Research Articles

Two-step quantum dialogue protocols against collective noises

By designing two-step transmissions, this paper presents two quantum dialogue (QD) protocols that can resist different types of collective noise in the quantum channel. The message carrier of the proposed scheme utilizes decoherence-free subspaces to remain invariant under the impact of collective noise. We employ combinations of these quantum states to form decoy photon pairs, ensuring secure transmission and preventing message distortion. Based on the principle that a single photon in an EPR pair reveals no information about its actual state, an EPR pair requires only one photon for protection during transmission. This property effectively reduces the number of decoy photons needed to ensure the security of quantum transmission, which can also be applied to the logical EPR pair consisting of logical qubits. A quantum logic circuit is also designed to demonstrate the practical implementation of shuffling the logical qubits within each logical EPR pair. Therefore, the proposed two-step QD protocols require only half as many decoy photons to achieve the same security level as other state-of-the-art QD schemes. The significant reduction in the utilization of decoy photons improves the qubit efficiency of the proposed QD protocols compared to other existing works in the field. Additionally, the security analysis of the proposed QD schemes ensures the absence of information leakage and resistance to common quantum attacks.

Efficient fault-tolerant quantum dialogue protocols using a quantum reordering circuit of EPR pairs

This study proposes two efficient fault-tolerant quantum dialogue (QD) protocols that are robust against the collective-dephasing and collective-rotation noises, respectively. In the proposed protocol, the message carriers are decoherence-free quantum states that are resistant to the corresponding collective noise, provided that all quantum photon pairs of a transmitted unit remain within the same time window. These quantum states and their combinations are used to compose the decoy photon pairs to ensure the security of the transmission. An observation on the Bell measurement has allowed an EPR pair as a message carrier to Require only one of its photons for protection. That is, the measurement of one single photon in an EPR pair will gain no information on its actual Bell state. This property has effectively reduced the number of decoy photons in quantum transmission. Since the photons used in the message carriers are particles of EPR pairs, the proposed two fault-tolerant QD protocols required only half of the decoy photons to ensure the same level of security. In the transmission, one photon of each EPR pair is separated using a reordering mechanism, and a quantum logic circuit is designed and implemented to demonstrate the concept in practice. The reduction of decoy photons has significantly improved the qubit efficiency of the proposed QD protocols compared with other relevant existing works. Furthermore, the proposed schemes also have no information leakage problem.

Quantum secure direct communication based on quantum homomorphic encryption

As one of the most important branches of quantum cryptography, quantum secure direct communication (QSDC) is used to transmit the secret message directly rather than distribute a random key. Quantum homomorphic encryption (QHE) enables arbitrary quantum transformation on encrypted data without decrypting the data. To date, the previously proposed QSDC schemes are mainly based on different quantum states. The research of the QSDC scheme based on QHE is still blank. In this paper, a QSDC scheme by taking advantage of the properties of QHE is proposed. The proposed protocol has applied QHE and decoy photons to prevent various types of attacks. The proposed scheme only utilizes the rotation operation to encode the secret message which is easy to implement with the current technologies. Moreover, the communication efficiency and the qubit-utilization ratio are analyzed in this paper, which shows that this protocol has good performance in the qubit-utilization ratio, and the qubit efficiency of the QSDC scheme has improved.

Three-party semi-quantum protocol for deterministic secure quantum dialogue based on GHZ states

In this paper, we propose a deterministic secure three-party semi-quantum dialogue (SQD) protocol based on the GHZ states as the initial quantum resource. In the protocol, three communicants can obtain secret message between each other to realize a secure three-party dialogue, one of them has quantum capabilities and the other two have classical abilities. The information leakage problem is prevented in the proposed three-party SQD protocol by using the entangled correlation between three particles in the same GHZ state. In addition, under the premise of introducing decoy photons, the communicants utilize twice eavesdropping detection and a process similar to one-time key encryption to ensure that the SQD protocol can resist multiple types of attacks, such as intercept-measure-resend attack, flip attack, man-in-the-middle attack, Trojan horse attack and entangle-measure attack. Finally, the protocol only involves single-photon measurement, which reduces the participants’ operations on the quantum superposition state and the demand for quantum devices.

Quantum Key Agreement Protocol Based on Quantum Search Algorithm

Quantum key agreement (QKA) and quantum search algorithm (QSA) are two important branches in quantum topic. The former asks all participants to negotiate the agreement key equally, and none of them can fully determine the agreement key. The latter is used to provide an acceleration in searching the marked item in an unsorted database. To date, several QKA schemes based on either BB84 or entangled states have been proposed, the QKA protocol based on QSA is rare, only exists one multi-party QKA (MQKA) protocol based on QSA. In this paper, on the basis of the properties of Grover’s QSA, the first two-party quantum key agreement protocol based on quantum search algorithm known as Grover’s algorithm is proposed. The participants transmit a two-particle quantum state sequence directly by inserting decoy photons randomly. The initial-prepared two-particle quantum states are easy to be prepared with current technology. Moreover, there is no swapping entanglement technology used in this protocol, it only needs unitary operations and single-particle measurements. Compared with the existing two-party QKA protocol, the proposed QKA protocol is more efficient. In addition, the security analysis shows that the proposed protocol is secure against both external attacks and internal ones. Finally, the proposed protocol is generated to MQKA protocol based on quantum search algorithm.

Greenberger-Horne-Zeilinger-based quantum private comparison protocol with bit-flipping

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.

Controlled quantum dialogue with authentication protocol on a basis of GHZ-like state

A controlled quantum dialogue with authentication protocol on a basis of GHZ-like state was proposed in this paper. To start with, three participants of the communication protocol generated a corresponding identity ID through quantum key distribution and it was kept secret. Controller Trent prepared the three-particle Greenberger–Home–Zeilinger-like (GHZ-like) state and shared with other two communication users Alice and Bob. Communication participants use the entangled particles in their respective hands which satisfy the nature of the classical XOR relationship for encryption, controlling and decryption of quantum messages and to verify the identities of communication users. Meanwhile, security of communication was assured by introducing decoy photons. According to analysis results, the proposed protocol can effectively not only prevent any form of eavesdropping behavior from external and internal eavesdroppers including the controller Trent, but also detect such activities. Finally, this protocol is proved to have high communication efficiency.

Quantum Controlled Teleportation of Bell State Using Seven-Qubit Entangled State

We present a theoretical scheme for quantum controlled teleportation, which transmits a Bell state from sender Alice to remote receiver Bob via a seven-qubit entangled state under the control of supervisor Charlie. The Bell state can be transmitted if Alice performs two GHZ-state measurements on her qubits and Charlie carries out a projection measurement on her qubit, respectively. Based on the measurement results of Alice and Charlie, the original quantum state can be reconstructed on Bob’s qubits via performing appropriate unitary operations. Moreover, we take comparisons with the previous schemes in five aspects of transmission qubits number, consumption of quantum resource, consumption of classical resources, success probability and intrinsic efficiency. And we also utilize decoy photons technology to ensure the security of the scheme under three kinds of attacks. We evaluated the scheme, and the results have proven that our proposed scheme has higher success probability, intrinsic efficiency and higher security.

New quantum key agreement protocol with five-qubit Brown states

We propose a new two-party quantum key agreement (QKA) protocol using five-qubit Brown states. One-way quantum transmission can be realized by merging Brown states and decoy photons randomly. The security of this protocol is shown to resist the outsider attack and participant attack over the ideal channel. Some methods are also proposed to ensure its security in noisy and lossy quantum channel. Finally, we generalize it and propose a multi-party QKA protocol based on Brown states.

New quantum key agreement protocols based on Bell states

We present a new two-party quantum key agreement (QKA) protocol based on Bell states. The participant transmits Bell states directly by inserting decoy photons in them randomly. The protocol is secure against the outsider attack and participant attack. Finally, it is generalized to multi-party QKA based on Bell states.

Multiparty Quantum Computation for Summation and Multiplication with Mutually Unbiased Bases

We present an efficient protocol to securely compute the summation and multiplication of the multiparty secure numbers via quantum states in MUBs. In our protocols, we assume the third party Alice is semi-honest which means Alice might want to steal the secret messages of the participants but cannot be corrupted by the participants. The agents use decoy photons which are randomly in one of 2dm nonorthogonal multiparticle states to prevent the eavesdropper and potential dishonest agents from freely eavesdropping on the secure information. The scheme requires the agents of computation to transmit fewer particles for multiparty summation and multiplication, which makes the scheme more convenient to use than others. Moreover, it has the advantage of having high information capacity per photon for summation and multiplication in multiparty quantum computation.

High-capacity quantum private comparison protocol with two-photon hyperentangled Bell states in multiple-degree of freedom

In this paper, the first high-capacity quantum private comparison (QPC) protocol is proposed to solve the comparison problem of equality of two parties’ secret inputs without revealing them out. This scheme is assisted with the semi-honest third party to fulfill the task. And the genuine two-photon hyperentangled Bell states are utilized as the important information carriers. Different from the previous protocols, this hyperentangled Bell states are composed of only two photons but characterize six qubits in two longitudinal momentum and polarization degrees of freedom (DOFs). In addition, this protocol possesses a higher information capacity and saves massive quantum resources for that the two-photon system can carry 6 bits of information. Meanwhile, this scheme can be applied and useful for long-distance quantum communication to improve the feasibility of QPC protocol. Furthermore, 64 nonorthogonal single-photon states as decoy photons are utilized to detect the security of the quantum channel. This method not only increases the security of the quantum channel, but also decreases the decoherence effect of environment noise. Moreover, this QPC protocol is analyzed to be immune to various kinds of attack. Finally, this QPC protocol can obtain the good application to compare the secret inputs securely, efficiently and feasibly.

High-capacity quantum secure direct communication with two-photon six-qubit hyperentangled states

This study proposes the first high-capacity quantum secure direct communication (QSDC) with two-photon six-qubit hyper-entangled Bell states in two longitudinal momentum and polarization degrees of freedom (DOFs) of photon pairs, which can be generated using two 0.5 mm-thick type-I β barium borate crystal slabs aligned one behind the other and an eight-hole screen. The secret message can be independently encoded on the photon pairs with 64 unitary operations in all three DOFs. This protocol has a higher capacity than previous QSDC protocols because each photon pair can carry 6 bits of information, not just 2 or 4 bits. Our QSDC protocol decreases the influence of decoherence from environment noise by exploiting the decoy photons to check the security of the transmission of the first photon sequence. Compared with two-way QSDC protocols, our QSDC protocol is immune to an attack by an eavesdropper using Trojan horse attack strategies because it is a one-way quantum communication. The QSDC protocol has good applications in the future quantum communication because of all these features.

High-Efficient Arbitrated Quantum Signature Scheme Based on Cluster States

The arbitrated quantum signature characteristics including the security and the efficiency are investigated and a new efficient and secure arbitrated quantum signature is proposed. It is shown that the proposed scheme exhibits an efficiency of 64 %. Furthermore, to gain a higher security, the decoy photons security checking is employed.

Quantum private comparison based on quantum dense coding

A serious problem in cloud computing is privacy information protection. This study proposes a new private comparison protocol using Einstein-Podolsky-Rosen (EPR) pairs. This protocol allows two parties to secretly compare their classical information. Quantum dense coding enables the comparison task to be completed with the help of a classical semi-honest center. A one-step transmission scheme and designed decoy photons can be used against various quantum attacks. The new protocol can ensure fairness, efficiency, and security. The classical semi-honest center cannot learn any information about the private inputs of the players. Moreover, this scheme can be easily generalized using the general EPR pairs in order to improve the transmission efficiency.

Deterministic Secure Quantum Communication and Authentication Protocol based on Extended GHZ-W State and Quantum One-time Pad

A deterministic secure quantum communication and authentication protocol based on extended GHZ-W state and quantum one-time pad is proposed. In the protocol, state |φ−〉 is used as the carrier. One photon of |φ−〉 state is sent to Alice, and Alice obtains a random key by measuring photons with bases determined by ID. The information of bases is secret to others except Alice and Bob. Extended GHZ-W states are used as decoy photons, the positions of which in information sequence are encoded with identity string ID of the legal user, and the eavesdropping detection rate reaches 81%. The eavesdropping detection based on extended GHZ-W state combines with authentication and the secret ID ensures the security of the protocol.

Efficient multi-party quantum key agreement by cluster states

A quantum key agreement (QKA) protocol by utilizing a four-photon cluster state is proposed in this paper. The proposed QKA protocol extends the two-party QKA protocol with four-qubit cluster state (Shen et al. in Quantum Inf Process 13:2313---2324, 2014) into a multi-party case. The block transmission technique and decoy photons method are used in the presented protocol. Meanwhile, the qubit efficiency of the presented protocol is also improved by using the dense coding method. Security analysis shows that the proposed protocol is secure against both participant and outside attacks.

Faithful Quantum Secure Communication with Authentication based on Bell States and Classical XOR Resisting Collective Noise

Two faithful quantum secure communication and authentication schemes based on Bell states and classical XOR operation are proposed, which withstand collective noises. The authentication and eavesdropping detection are completed by using logical decoy photons generating by previously shared identity string. The logical decoy photons are decoherence-free states over the two collective noisy channels respectively. The transmission of secret message is a one-time pad system, which guarantees the absolute security of secret message. Encoding secret message after particle transmission ensures the accuracy of secret message.

Robust Anti-Collective Noise Quantum Secure Direct Dialogue Using Logical Bell States

In this paper we propose two quantum secure direct dialogue (QSDD) schemes with logical Bell states which can resist collective noise. The two users Alice and Bob encode their secret messages with the help of unitary operations. Compared with many quantum secure direct communication (QSDC), there is no strict information sender and receiver in these schemes, one logical Bell state can be operated twice by Alice and Bob based on what messages they prefer to encode. As a result, the two users are able to share their messages mutually, so the efficiency of communication is improved. By rearranging the order of particles and inserting decoy photons, our protocols are able to avoid the information leakage and detect eavesdropping, and they can be proved to have unconditional security.

Controlled Deterministic Secure Quantum Communication Protocol Based on Three-Particle GHZ States in X-Basis* Supported by the National Natural Science Foundation of China under Grant No. 61402058, Science and Technology, Sichuan Province of China under Grant No. 2013GZX0137, Fund for Young Persons Project of Sichuan Province of China under Grant No. 12ZB017, and the Foundation of Cyberspace Security Key Laboratory of

A controlled deterministic secure quantum communication (CDSQC) protocol is proposed based on three-particle GHZ state in X-basis. Only X-basis and Z1Z2X3-basis (composed of Z-basis and X-basis) measurement are required, which makes the scheme more convenient than others in practical applications. By distributing a random key between both sides of the communication and performing classical XOR operation, we realize a one-time-pad scheme, therefore our protocol achieves unconditional secure. Because only user with legitimate identity string can decrypt the secret, our protocol can resist man-in-the middle attack. The three-particle GHZ state in X-basis is used as decoy photons to detect eavesdropping. The detection rate reaches 75% per qubit.