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.
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.
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.
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.
In response to the demand for identity authentication in quantum secure direct communication, this paper proposes a quantum secure direct communication scheme based on a mixture of single photon and Bell state, by combining the bidirectional identity authentication. Before communication begins, both parties share a series of secret information to prepare a series of single photon and Bell state particles. Encoding four single photons and four Bell states yields eight types of encoded information, followed by identity authentication. The first step in identity authentication is to use a single photon to verify the legitimacy of the receiver. If the error exceeds the given threshold, it indicates the presence of eavesdropping. Otherwise, the channel is safe. Then, Bell state particles are used to verify the legitimacy of the sender, and the threshold is also used to determine whether there is eavesdropping. The present method is the same as previous one. If the error rate is higher than the given threshold, it indicates the existence of third-party eavesdropping. Otherwise, it indicates that the channel is secure. As for the specific verification method, it will be explained in detail in the article. Afterwards, Bell state particles are mixed with a single photon as a transmission carrier, and eavesdropping detection particles are added whenever the quantum state is sent. However, once the eavesdropper intercepts the transmitted particles, owing to incomplete information obtained, the eavesdropper is unable to recover the original information, and the eavesdropping behavior will be immediately detected, thus terminating communication. In this scheme, single photon and Bell states are fully utilized, and hybrid communication can effectively improve transmission efficiency, encoding capability, and quantum bit utilization. Security analysis shows that this scheme can resist common external and internal attacks such as interception/measurement replay attacks, auxiliary particle attacks, and identity impersonation attacks. The analysis of efficiency and encoding capacity shows that the transmission efficiency of this scheme is 1, the encoding capacity is 3 bits per state, and the quantum bit utilization rate is 1. Compared with other schemes, this scheme has significant advantages because it uses different particles for bidirectional authentication, making it more difficult for attackers to crack, and thus it has higher security than traditional schemes.