A quantum high secure direct communication with authentication protocol is proposed by using single photons. The high security of the protocol is achieved on levels. The first level involves the verification of the quantum channel security by using fake photons. The authentication process is also ensured by the fake photons. The second level of security is given by the use of multiple polarization bases. The secret message is encoded in groups of photons; each single character of the message is associated with m (m≥7) photons. Thus, at least 27(128) characters will be encoded. In order to defeat the quantum teleportation attack, the string of bits associated to the secret message is encrypted with a secret string of bits by using XOR operator. Encryption of the sender's identity string and the receiver's identity string by the XOR operator with a random string of fake photons defends quantum man-in-the-middle attack efficiently. Quantum memory is required to implement our protocol. Storage of quantum information is a key element in quantum information processing and provides a more flexible, effective and efficient communication. Our protocol is feasible with current technologies.
A quantum high secure direct communication with authentication protocol is proposed by using single photons. The high security of the protocol is achieved on levels. The first level involves the verification of the quantum channel security by using fake photons. The authentication process is also ensured by the fake photons. The second level of security is given by the use of multiple polarization bases. The secret message is encoded in groups of photons; each single character of the message is associated with m (m≥7) photons. Thus, at least 27(128) characters will be encoded. In order to defeat the quantum teleportation attack, the string of bits associated to the secret message is encrypted with a secret string of bits by using XOR operator. Encryption of the sender's identity string and the receiver's identity string by the XOR operator with a random string of fake photons defends quantum man-in-the-middle attack efficiently. Quantum memory is required to implement our protocol. Storage of quantum information is a key element in quantum information processing and provides a more flexible, effective and efficient communication. Our protocol is feasible with current technologies.
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.
The security of Quantum Secure Direct Communication (QSDC) and its authentication procedure based on multiple stages is analyzed. The security analysis shows that the process of authentication is required to be done three times based on the usage of unitary transformation that is only known between Alice and Bob. In the proposed protocol, a secure quantum handshake is utilized to share the secret polarization angle and an authentication key at the initial stage of authentication over the quantum channel. The symmetry key is used in this work to protect user data communication within the QSDC protocol, where the same secret key is used to encrypt and decrypt the message. This work adopts the information travel time (ITT) by allowing the sender to detect any interference from third parties. In addition, the operation of the Pauli-X quantum gate increases Eve’s difficulty in stealing the information. The information transmitted is then continued by sending photons once in the quantum channel, which improves the efficiency without losing the message’s security. In addition, to securely transfer the stream of messages, the proposed protocol is operated in single-stage, and the authentication is applied bit-by-bit, thus reducing the transmission time. Security checks are carried out along the data transmission process. Compared to previous protocols, this new initial authentication protocol has remarkable advantages since it does not require public communication to pre-share the authentication key and secret angles before the onset of the transmission, therefore, reducing the communication cost. Moreover, the secret authentication key and polarization angles are updated after a number of bits are sent to increase the security level. The verification process is also conducted to ensure the symmetry of the sender and receiver. The analyses presented herein demonstrate that the proposed authentication protocol is simple and secure in order to ensure the legitimacy of the users.
A multiparty controlled bidirectional quantum secure direct communication and authentication protocol is proposed based on EPR pair and entanglement swapping. The legitimate identities of communicating parties are encoded to Bell states which act as a detection sequence. Secret messages are transmitted by using the classical XOR operation, which serves as a one-time-pad. No photon with secret information transmits in the quantum channel. Compared with the protocols proposed by Wang et al. [Acta Phys. Sin. 56 (2007) 673; Opt. Commun. 266 (2006) 732 ], the protocol in this study implements bidirectional communication and authentication, which defends most attacks including the 'man-in-the-middle' attack efficiently.
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.
Semiquantum cryptography has drawn much attention in recent years since it simplifies the implementation of quantum cryptographic protocols. In this paper, we study semiquantum secure direct communication (SQSDC). Based on single-photons, we propose a two-step SQSDC protocol with identity authentication, which can be used to prevent impersonation and the man-in-the-middle attack. Different from previous protocols based on quantum entanglement or quantum memory, our protocol removes there restrictions for simplifying its physical implementation. We prove that our two-step SQSDC protocol is completely robust. That is, any adversarial attempting to learn some information on the secure message or identity strings will inevitably induce some errors that can be detected by communicators.
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.