The proposed protocols of quantum secure direct communication based on single photons up-to-date are almost two-way communication protocols, in which the probability of Trojan horse attack reduces the security of the communication. The aim of photons transferred forward and backward is to let the receiver know the code bases and the initial states of the photons. One-way quantum secure direct communication protocol based on single photons is proposed, in which the XOR operation by bits of the information sequence and random sequence is taken before coding. Then the code bases and the random sequence can be published if the quantum channel is secure, so the receiver can measure in the correct basis to get the information; even there exists eavesdropper, the information sequence is still secure. This protocol has the advantages of higher security, longer communication distance compared with two-way scheme and easier implementation than others.
The proposed protocols of quantum secure direct communication based on single photons up-to-date are almost two-way communication protocols, in which the probability of Trojan horse attack reduces the security of the communication. The aim of photons transferred forward and backward is to let the receiver know the code bases and the initial states of the photons. One-way quantum secure direct communication protocol based on single photons is proposed, in which the XOR operation by bits of the information sequence and random sequence is taken before coding. Then the code bases and the random sequence can be published if the quantum channel is secure, so the receiver can measure in the correct basis to get the information; even there exists eavesdropper, the information sequence is still secure. This protocol has the advantages of higher security, longer communication distance compared with two-way scheme and easier implementation than others.
One-way deterministic secure quantum communication protocol based on single photons is proposed in this paper, in which the XOR operation by bits of the information sequence and random sequence is performed and the checking sequence is inserted before the sender’s coding operation. When the photons arrive at the receiver, they are delayed at the receiver, and the sender then publishes the coding basis, so the photons can be measured in the correct basis. Then the two parties estimate the security of the quantum channel by the checking bits. When the channel is secure the sender publishes the random bits where the receiver has results, and the information sequence can be recovered by the receiver. Even the channel is not secure, what the eavesdropper gets is the random sending sequence, the information sequence is still secure. This protocol has the advantages of higher transmission efficiency and easier implementation compared with the two-way communication.
Two-way quantum secure communication protocol and one-way quantum secure communication protocol based on single photon sequence and the XOR operation have been proposed, one-way communication can confuse the eavesdroppers and two-way communication only a single authentication and there is not visible to eavesdropping and delayed photon attack Trojan horse attack. The new agreement the use of single photon sequence and no regularity not only to achieve unconditional security, and semantics confuse eavesdroppers and has a high transmission efficiency, easy implementation, especially suitable for use in noisy channels.
One-way quantum secure communication protocol based on single photon sequence and the XOR operation have been proposed, one-way communication can confuse the eavesdroppers and there is not visible to eavesdropping and delayed photon attack Trojan horse attack. The new agreement the use of single photon sequence and no regularity not only to achieve unconditional security, and semantics confuse eavesdroppers and has a high transmission efficiency, easy implementation, especially suitable for use in noisy channels.
By studying the properties of the mixture of Bell state particles and single photons,in the paper we design a quantum code scheme with high coding capacity,and propose a novel quantum secure direct communication protocol with high transmission efficiency.Alice prepares Bell state particles and single photons,and divides Bell state particles into two sequences SA and SB.SB is sent to Bob for the first security check through using quantum correlation properties of particles.When the check result shows that the quantum channel is safe,by using the designed quantum code scheme, Alice encodes her classical message on the mixed quantum state sequence of Bell sequence SA and single photon sequence SS.Then,some single photons that are used for security check are re-inserted randomly into the encoded sequence,and the order of particles is rearranged to ensure checking Eve's attack.Alice sends the new sequence to Bob.Bob delays and receives it.And then,the quantum channel conducts the second-time security check.The transmission error rate is calculated,and if the error rate is lower than the tolerance threshold,the channel is safe.Bob decodes and reads Alice's message.The first security check is to determine whether quantum channel is safe.The second security check is to test whether there are eavesdroppers during information transmission.Safety analysis is done by applying the quantum information theory for the proposed protocol.The error rate introduced by Eve and the amount of information by Eve are calculated.It is shown that this pro-tocol can effectively resist measurement-resend attack,intercept-resend attack, auxiliary particle attack,denial of service attack and Trojan attack.Among them,auxiliary particle attack is analyzed in detail.The transmission efficiency and coding capacity are also analyzed.The transmission efficiency is 2,the quantum bit rate is 1,and the coding capacity is that a quantum state can encode three bits of classical messages.We also compare the proposed protocol with many existing popular protocols in the sense of efficiency,e.g.,Ping-Pong protocol, Deng F G et al.'s two-step and one-pad-time quantum secure direct communication protocol,Wang J et al.'s quantum secure direct communication protocol based on entanglement swapping and Quan D X et al.'s one-way quantum secure direct communication protocol based on single photon.It is proved that this proposed protocol has higher transmission efficiency.In addition,neither complex U operation nor entanglement swapping is used,and implementation process is simplified.However,this protocol is devoted to theoretical research of quantum secure direct communication.There are still some difficulties in the practical application.For example,the storage technology of quantum states is not mature at present.It is not easy to prepare and measure Bell state particles nor to combine them with single photons,and so on.The implementation of this protocol depends on the development of quantum technology in the future.
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) can transmit secret messages directly from one user to another without first establishing a shared secret key, which is different from quantum key distribution. In this paper, we propose a novel quantum secure direct communication protocol based on signal photons and Bell states. Before the execution of the proposed protocol, two participants Alice and Bob exchange their corresponding identity IDA and IDB through quantum key distribution and keep them secret, respectively. Then the message sender, Alice, encodes each secret message bit into two single photons (| 01〉or|10〉) or a Bell state , and composes an ordered secret message sequence. To insure the security of communication, Alice also prepares the decoy photons and inserts them into secret message sequence on the basis of the values of IDA and IDB. By the secret identity IDA and IDB, both sides of the communication can check eavesdropping and identify each other. The proposed protocol not only completes secure direct communication, but also realizes the mutual authentication. The security analysis of the proposed protocol is presented in the paper. The analysis results show that this protocol is secure against some common attacks, and no secret message leaks even if the messages are broken. Compared with the two-way QSDC protocols, the presented protocol is a one-way quantum communication protocol which has the immunity to Trojan horse attack. Furthermore, our proposed protocol can be realized without quantum memory.