Losses in a quantum channel do not allow deterministic communication. We propose a two-way six-state deterministic secure quantum communication scheme that is robust in a lossy channel. Our protocol can be used for two purposes: (a) establishment of a deterministic key, and (b) direct communication of a secret message. Our protocol is directly integrable with the decoy state method while achieving deterministic communication without using a quantum memory. In our protocol, a legitimate party has the control to assign a desired bit value to a successfully transmitted qubit in the public discussion step. Before the public discussion, no information is leaked to the eavesdropper (Eve) even if all the qubits are measured or prepared by her. Hence, our scheme is used as a quantum direct communication (QDC) protocol, to meet the quality of service requirement of swift data communication. We compare the security of our protocol against the photon number splitting attack in the absence of the decoy state method with two QDC protocols. We compute the success probability of Eve when our protocol is used as a multiparty key distribution scheme. We also propose the criteria to compute the efficiency of QDC protocols.
Losses in a quantum channel do not allow deterministic communication. We propose a two-way six-state deterministic secure quantum communication scheme that is robust in a lossy channel. Our protocol can be used for two purposes: (a) establishment of a deterministic key, and (b) direct communication of a secret message. Our protocol is directly integrable with the decoy state method while achieving deterministic communication without using a quantum memory. In our protocol, a legitimate party has the control to assign a desired bit value to a successfully transmitted qubit in the public discussion step. Before the public discussion, no information is leaked to the eavesdropper (Eve) even if all the qubits are measured or prepared by her. Hence, our scheme is used as a quantum direct communication (QDC) protocol, to meet the quality of service requirement of swift data communication. We compare the security of our protocol against the photon number splitting attack in the absence of the decoy state method with two QDC protocols. We compute the success probability of Eve when our protocol is used as a multiparty key distribution scheme. We also propose the criteria to compute the efficiency of QDC protocols.
A novel deterministic secure quantum communication(DSQC)scheme is presented based on EinsteinPodolsky-Rosen(EPR)pairs and single photons in this study.In this scheme,the secret message can be encoded directly on the first particles of the prepared Bell states by simple unitary operations and decoded by performing the Bell-basis measurement after the additional classic information is exchanged.In addition,the strategy with two-step transmission of quantum data blocks and the technique of decoy-particle checking both are exploited to guarantee the security of the communication.Compared with some previous DSQC schemes,this scheme not only has a higher resource capacity,intrinsic efciency and total efciency,but also is more realizable in practical applications.Security analysis shows that the proposed scheme is unconditionally secure against various attacks over an ideal quantum channel and still conditionally robust over a noisy and lossy quantum channel.
A novel deterministic secure quantum communication (DSQC) scheme is presented based on Einstein-Podolsky-Rosen (EPR) pairs and single photons in this study. In this scheme, the secret message can be encoded directly on the first particles of the prepared Bell states by simple unitary operations and decoded by performing the Bell-basis measurement after the additional classic information is exchanged. In addition, the strategy with two-step transmission of quantum data blocks and the technique of decoy-particle checking both are exploited to guarantee the security of the communication. Compared with some previous DSQC schemes, this scheme not only has a higher resource capacity, intrinsic efficiency and total efficiency, but also is more realizable in practical applications. Security analysis shows that the proposed scheme is unconditionally secure against various attacks over an ideal quantum channel and still conditionally robust over a noisy and lossy quantum channel.
Quantum key distribution (QKD) is considered as an ideal method to make secret message unreadable to eaves-dropper but intelligible to the two authorized parties of the communication [1][2][3][4][5][6].In the research of experimental quantum key distribution, single photons and entangled photon pairs are used as the carriers.In quantum key distribution, secret keys are generated first between the communication parties.The security of quantum key distribution is guaranteed by the laws of quantum mechanics.After the quantum key distribution is completed, the communication parties should share secret keys, then the sender encrypts the secret message using the secret keys to form the ciphertext and transmits the ciphertext through a classical channel.The receiver receives the ciphertext and then decrypt the ciphertext to get the secret message.Altogether there are four steps in a secret communication process with QKD: key generation, encryption, transmission and decryption.Here in this review, we review some new development in quantum communication, quantum direct communication (QDC).Quantum direct communication is a form of quantum communication where secret messages can be transmitted through a quantum channel with or without additional classical communications.There are two forms of quantum direct communication, quantum secure direct communication (QSDC) [7{9] and deterministic secure quantum communication (DSQC) [10,11].In QSDC, secret messages are transmitted directly between the communication parties, from sender Alice to receiver Bob, without additional classical communication except those for the necessary eavesdropping check.In other words, the quantum key distribution process and the classical communication of ciphertext are condensed into one single quantum communication procedure in QSDC.Deterministic secure quantum communication is another type of quantum direct communication, such as those proposed in Ref. [10,11], where classical communication is required in order to read out the secret message.As mentioned earlier, to complete a secure communication with the help of QKD, one usually encodes the secret message with an encryption scheme, and the ciphered text is transmitted through a classical channel.With a quantum channel, this procedure can be varied.
We present a novel protocol for deterministic secure quantum communication by using the four-qubit cluster state as quantum channel. It is shown that two legitimate users can directly transmit the secret messages based on Bell-basis measurements and classical communication. The present protocol makes use of the ideas of block transmission and decoy particle checking technique. It has a high capacity as each cluster state can carry two bits of information, and has a high intrinsic efficiency because almost all the instances except the decoy checking particles (its number is negligible) are useful. Furthermore, this protocol is feasible with present-day technique.
Quantum communication is an important branch of quantum technology. It can safely transmit private information between legitimate parties and its unconditional security is guaranteed by quantum physics. So far, deterministic secure quantum communication without entanglement usually transmits single photons in two-way quantum channels. We propose a deterministic secure quantum communication proposal, and it requires a one-way quantum channel and a classical channel. In our protocol, a sender encodes logical bits by using two conjugate bases consisting of the polarization and time-bin degrees of freedom of a photon and transmits it to a receiver over a quantum channel. Upon receiving this photon, the receiver measures it randomly in two bases and can decode the bit deterministically with the help of the sender. Any attack from eavesdroppers will be detected by the legitimate parties. Furthermore, this protocol can be implemented with linear-optic elements and single-photon detectors.
Quantum secure direct communication (QSDC) is one of the most important branches of quantum communication. In contrast to the quantum key distribution (QKD) which distributes a secure key between distant parties, QSDC directly transmits secret message instead of sharing key in advance. To establish a secure QSDC protocol, on the one hand, the security of the quantum channel should be confirmed before the exchange of the secret message. On the other hand, the quantum state should be transmitted in a quantum data block since the security of QSDC is based on the error rate analysis in the theories on statistics. Compared with the deterministic quantum key distribution (DQKD) which can also be used to transmit deterministic information, QSDC schemes do not need extra classical bits to read the secret message except for public discussion. In this article, we introduce the basic principles of QSDC and review the development in this field by introducing typical QSDC protocols chronologically. The first QSDC protocol was proposed by Long and Liu, which can be used to establish a common key between distant parties. In their scheme, the method for transmitting quantum states in a block by block way and in multiple steps was proposed and the information leakage before eavesdropping detection was solved. Subsequently, Deng et al. presented two pioneering QSDC schemes, an entangled-state-based two-step QSDC scheme and a single-photon-state-based quantum one-time pad scheme, in which the basic principle and criteria for QSDC were pointed out. From then on, many interesting QSDC schemes have been proposed, including the high-dimension QSDC scheme based on quantum superdense coding, multi-step QSDC scheme based on Greenberger-Horne-Zeilinger states, QSDC scheme based on quantum encryption with practical non-maximally entangled quantum channel, and so on. We also introduce the anti-noise QSDC schemes which were designed for coping with the collective-dephasing noise and the collective-rotation noise, respectively. In 2011, Wang et al. presented the first QSDC which exploited the hyperentangled state as the information carrier and several QSDC schemes based on the spatial degree of freedom (DOF) of photon, single-photon multi-DOF state and hyperentanglement were proposed subsequently. In addition to the point-to-point QSDC schemes, we also review the QSDC networks. Finally, a perspective of QSDC research is given in the last section.