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.
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.
Quantum secure direct communication (QSDC) enables secure message transmission without needing pre-shared keys. To enhance the practical reliability of QSDC systems, measurement-device-independent (MDI) protocols have emerged, providing robust security in real-world applications. Despite the advantages of MDI protocols, their implementation has not yet accomplished communication using only single photons which are advantageous due to their ease of preparation and transmission. In this letter, by employing single photons, we propose a novel MDI-QSDC protocol with identity authentication. This protocol achieves mutual identity authentication between the communicating parties, Alice and Bob, enabling authenticated Alice to securely transmit her secret message directly to authenticated Bob. Theoretical analysis demonstrates the protocol is resilient to identity and message security threats. Simulations with practical experimental parameters and efficiency analysis highlight its potential in quantum communication.
Quantum secure direct communication (QSDC) enables direct private message transmission over quantum channels without pre-shared keys. This paper proposes a QSDC protocol based on two-step line-based quantum walks (QWs), which involves sender Alice, receiver Bob and an untrusted third party Charlie, and three stages consisting of preparing, checking quantum channel and communicating secret messages. In the first stage, Bob generates entangled states as the desired quantum channel via one-step QW and prepares decoy photons for the subsequent security checking of the quantum channel; In the second stage, Bob first sends a sequence comprising the photons from the entangled states and Bob’s decoy photons to Alice, who forwards Bob’s decoy photons along with her own decoy photons to Charlie for measurement, with Alice and Bob verifying security by comparing the measurement outcomes; In the third stage, Alice prepares a sequence of photons as coin state for encoding messages to be communicated, which along with the prepared entangled states form a quantum teleportation system, which completes the transmission of the messages under the dominance of another-step QW. Security analyses show the suggested protocol can resist against intercept-and-resend and measure-and-resend attacks, promoting the QSDC’s practicality via QW-based entanglement generation, simplified measurement operations and security checking under the assistance of the third party Charlie.
Abstract Multipartite quantum secure direct communication (MQSDC) enables multiple message senders to simultaneously and independently transmit secret messages to a message receiver through quantum channels without sharing keys. Existing MQSDC protocols all assume that all the communication parties are legal, which is difficult to guarantee in practical applications. In this study, a single‐photon based three‐party QSDC protocol with identity authentication is proposed. In the protocol, the message receiver first authenticates the identity of two practical message senders. Only when the identity authentication is passed, the legal message senders can encode their messages by the hyper‐encoding technology. In theory, two bits of messages can be transmitted to the message receiver in a communication round. The protocol can resist the external attack and internal attack, and guarantee the security of the transmitted messages and the identity codes of each legal message sender. The secret message capacity of the protocol is simulated with two‐decoy‐state method. The maximal communication distance between any two communication parties can reach 31.75 km with weak signal and decoy state pulses. The three‐party QSDC protocol can be extended to a general MQSDC protocol and has important application in the further practical MQSDC field.
Abstract Recently, Yan et al . proposed a quantum secure direct communication (QSDC) protocol with authentication using single photons and Einstein-Podolsky-Rosen (EPR) pairs ( Yan L. et al ., Comput. Mater. Contin. , 63 (2020) 1297). In this work, we show that the above QSDC protocol is secure neither against intercept-and-resend attack, nor against impersonation attack. With any of these two types of attacks, an eavesdropper can recover the full secret message. We also propose a suitable modification of this protocol, which not only defeats the above attacks, but also resists all other common attacks. Thus, our modified protocol provides an improvement over the existing one in terms of security.
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.
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.