Method and apparatus for unidirectional transmission of quantum communication

Abstract

The application provides a one-way transmission quantum communication method and device, a key is shared between user terminals in advance; a single photon is prepared according to the key, and information to be transmitted is encoded on the single photon quantum state, and then the encoded single photon is transmitted to an information receiving terminal through a quantum channel; after receiving the encoded single photon, the information receiving terminal performs eavesdropping detection on the quantum channel by using the single photon to be transmitted, confirms the security of the channel, and then reads the single photon information by using the shared key, and the information transmission is completed. The quantum state of the quantum direct communication method provided by the application needs to be transmitted only once in the channel, the loss is smaller, the transmission distance is longer, the block transmission technology is not needed, the dependence of the two-way protocol on the quantum storage technology is eliminated, and the practicability is better.

Description

Technical Field

[0001] This invention relates to the field of quantum communication technology, and in particular to a one-way quantum communication method and apparatus. Background Technology

[0002] Unlike traditional communication, the unconditional security of quantum communication is guaranteed by physical principles, and its high security has attracted widespread international attention. Currently, quantum communication includes several mainstream research directions: quantum secure direct communication (QSDC) and quantum key distribution (QKD). QKD first securely distributes keys through a quantum channel, then transmits encrypted information using a classical channel; the generated secure key can be combined with the one-time pad of classical cryptography, which has been proven to be unconditionally secure. However, when the same key is reused, its security is compromised, thus requiring a large number of keys for transmission, hindering its subsequent promotion and use. Quantum secure direct communication, on the other hand, is a highly secure and reliable communication method that directly transmits the quantum state of loaded information between two parties over a long distance using a quantum channel, achieving secure direct transmission of information. To ensure secure information transmission, quantum secure direct communication has proposed various secure bidirectional transmission protocols, including two-step protocols and the DL04 protocol. These bidirectional protocols employ a method where Bob at the user end prepares a batch of quantum states and transmits them to Alice at the user end using block transmission technology. Both parties then perform eavesdropping detection on the quantum channel. After confirming channel security, Alice transmits the quantum states back to Bob. While this process effectively ensures information security, the quantum states need to be transmitted twice within the quantum channel, resulting in significant losses and short transmission distances. Furthermore, block transmission technology requires quantum storage, but current quantum storage technology remains immature and difficult to implement practically. Summary of the Invention

[0003] This invention provides a one-way quantum communication method and apparatus to overcome the shortcomings of existing technologies, such as high loss, short transmission distance, and low practicality, and to achieve communication with lower loss, longer transmission distance, and better practicality.

[0004] This invention provides a one-way quantum communication method for an information transmitting end, comprising:

[0005] The information to be transmitted is acquired and pre-encoded to generate a digital string to be transmitted; the digital string to be transmitted includes an information part and a detection part.

[0006] A first key and a second key of the same length as the data string to be transmitted are extracted from two sets of random numbers, wherein the two sets of random numbers are shared in advance by the information sending end and the information receiving end;

[0007] Based on preset rules, a single photon is prepared using the first key and the second key;

[0008] The single photon is encoded according to the digital string to be transmitted to obtain the single photon to be transmitted, and the single photon to be transmitted is sent to the information receiving end one by one; the single photon to be transmitted carries the current transmission ciphertext.

[0009] According to a one-way quantum communication method provided by the present invention, the method involves acquiring information to be transmitted and pre-encoding the information to be transmitted to generate a digital string to be transmitted, specifically including:

[0010] Obtain the information to be transmitted and convert it into a binary number string;

[0011] The binary digit string is pre-encoded using an error correction encoder to obtain an encoded digit string;

[0012] A set of random numbers is randomly generated and randomly inserted into the encoded number string to obtain the number string to be transmitted.

[0013] According to a one-way quantum communication method provided by the present invention, the preset rules include:

[0014] The first key is used for selecting the basis vectors between the information sending end and the information receiving end for synchronization;

[0015] The second key is used to select the quantum state of a single photon.

[0016] According to a one-way quantum communication method provided by the present invention, a single photon is encoded according to the digital string to be transmitted to obtain the single photon to be transmitted, specifically including:

[0017] If the value in the string of numbers to be transmitted is 0, then a quantum gate operation U0 = I is performed on the single photon;

[0018] If the value in the transmitted digital string is 1, then U1 = iσ is applied to the single photon. y Quantum gate operations, where σ y It is the Pauli-y matrix.

[0019] According to the present invention, a one-way quantum communication method is provided, wherein the transmitted ciphertext specifically includes:

[0020] The information portion of the digital string to be transmitted is modulo 2 sum of the second key value.

[0021] This invention also provides a one-way quantum communication method for an information receiving end, comprising:

[0022] Acquire the single photon to be transmitted from the information sending end;

[0023] The first key distributed by the information sending end is used to select the measurement basis vector to measure the received single photon to be transmitted, and the second key distributed by the information sending end is used to extract the measurement result, which includes information bit value and detection bit value.

[0024] Obtain the position and value of the single photon used for detection from the information transmitting end;

[0025] The position and value of the single photon used for detection are compared with the measurement results to calculate the bit error rate of the current transmission.

[0026] If the bit error rate of the quantum bit is lower than a preset threshold, transmission continues, and the measurement result is decoded to obtain the information to be transmitted.

[0027] According to a one-way quantum communication method provided by the present invention, the measurement result is decoded to obtain the information to be transmitted, specifically including:

[0028] The detection portion is removed from the measurement results to obtain the information measurement results;

[0029] The information measurement results are decoded using an error correction decoder to obtain the information to be transmitted;

[0030] The detection section includes the position and value of the single photon obtained from the information transmitting end for detection.

[0031] According to a one-way quantum communication method provided by the present invention, the position and value of a single photon used for detection are compared with the measurement result to determine the bit error rate of the current transmission, and the method further includes:

[0032] If the bit error rate of the quantum bit is equal to or higher than a preset threshold, then the transmission is terminated and the random number is reset; and / or,

[0033] Two new keys are extracted from the transmitted ciphertext after removing the detection bits and stored in a shared key pool.

[0034] According to the present invention, a one-way quantum communication method is provided, wherein the transmitted ciphertext specifically includes:

[0035] After obtaining the position and value of the single photon used for detection from the information sending end, the numerical string obtained by discarding the corresponding values ​​of the measurement result.

[0036] This invention provides a one-way quantum communication device for information transmission, comprising:

[0037] An information precoding unit is used to acquire information to be transmitted and precode the information to be transmitted to generate a digital string to be transmitted; the digital string to be transmitted includes an information part and a detection part.

[0038] A key extraction unit is used to extract a first key and a second key of the same length as the data string to be transmitted from two sets of random numbers, wherein the two sets of random numbers are shared in advance by the information sending end and the information receiving end;

[0039] A single-photon preparation unit is used to prepare single photons based on preset rules using the first key and the second key.

[0040] A single-photon encoding and transmitting unit is used to encode the single photon according to the digital string to be transmitted to obtain the single photon to be transmitted, and to send the single photon to be transmitted one by one to the information receiving end; the single photon to be transmitted carries the current transmission ciphertext.

[0041] The present invention also provides a one-way quantum communication device for an information receiving end, comprising:

[0042] A single-photon receiving unit is used to acquire the single photon to be transmitted by the information sending end.

[0043] A single-photon measurement unit is used to select a measurement basis vector using a first key distributed by the information transmitter to measure the received single photon to be transmitted, and to extract the measurement result using a second key distributed by the information transmitter to obtain the measurement result, which includes information bit value and detection bit value.

[0044] A single-photon detection acquisition unit is used to acquire the position and value of the single photon to be detected obtained from the information transmitting end;

[0045] The security verification unit is used to compare and calculate the position and value of the single photon used for detection with the measurement result to determine the bit error rate of the current transmission.

[0046] The decoding unit is used to continue transmission if the bit error rate of the qubit is lower than a preset threshold, and to decode the measurement result to obtain the information to be transmitted.

[0047] The present invention also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the one-way quantum communication method as described above.

[0048] The present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the one-way quantum communication method as described above.

[0049] This invention provides a one-way quantum communication method and apparatus. The method for an information transmitter includes: acquiring information to be transmitted and pre-encoding the information to generate a digital string to be transmitted; the digital string to be transmitted includes an information portion and a detection portion; extracting a first key and a second key of equal length to the digital string to be transmitted from two sets of random numbers, wherein the two sets of random numbers are pre-shared by the information transmitter and the information receiver; preparing single photons based on preset rules using the first key and the second key; encoding the single photons according to the digital string to be transmitted to obtain single photons to be transmitted, and transmitting the single photons to be transmitted one by one to the information receiver; the single photons to be transmitted carry the currently transmitted ciphertext. The method for an information receiving end includes: acquiring a single photon to be transmitted from an information sending end; selecting a measurement basis vector using a first key distributed by the information sending end to measure the received single photon to be transmitted, and extracting the measurement result using a second key distributed by the information sending end to obtain a measurement result, the measurement result including an information bit value and a detection bit value; acquiring the position and value of a single photon to be detected obtained by the information sending end; comparing and calculating the position and value of the single photon to be detected with the measurement result to determine the qubit error rate of this transmission; if the qubit error rate is lower than a preset threshold, continuing transmission, and decoding the measurement result to obtain the information to be transmitted. The information sending end of this invention acquires the information to be transmitted, pre-encodes the information into a digital string to be transmitted, prepares a single photon based on a first key and a second key extracted from a random number shared with the information receiving end in advance, encodes the single photon according to the digital string to be transmitted, and sends the encoded single photon to be transmitted to the information receiving end. The information transmitting end of this invention generates and transmits single-photon qubits based on a key shared in advance with the information receiving end and the information to be transmitted, avoiding the use of block transmission technology, eliminating the dependence of bidirectional protocols on quantum storage technology, and increasing practicality.

[0050] The information receiving end of this invention uses a first key and a second key to measure the received single photon to be transmitted, and compares the measurement result with the position and value of the single photon to be detected disclosed by the information sending end. The calculated result is then compared with a preset threshold for security judgment. After security is confirmed, the test result is decoded to obtain the information to be transmitted. The information receiving end of this invention receives and measures single photon qubits according to a key shared with the information sending end in advance, and directly uses the single photon to be transmitted for quantum channel eavesdropping detection. The quantum state only needs to be transmitted once in the channel, resulting in less loss and a longer transmission distance.

[0051] This invention first pre-shares a key between user terminals. The sending end prepares a single photon based on this key and encodes the information to be transmitted onto the single photon's quantum state. Then, it sends the encoded single photon to the receiving end through a quantum channel. Upon receiving the encoded single photon, the receiving end uses the transmitted single photon to perform eavesdropping detection on the quantum channel to confirm its security. Finally, it uses the pre-shared key to read the single photon information, completing the information transmission. The quantum direct communication method provided by this invention requires the quantum state to be transmitted only once in the channel, resulting in less loss, longer transmission distance, and eliminating the need for block transmission technology. This also eliminates the dependence of bidirectional protocols on quantum storage technology, making it more practical. Attached Figure Description

[0052] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0053] Figure 1 One of the flowcharts of a one-way quantum communication method for information transmission provided by the present invention;

[0054] Figure 2 Flowchart 2 of a one-way quantum communication method for information receiving end;

[0055] Figure 3 This is the third flowchart illustrating the one-way quantum communication method provided by the present invention;

[0056] Figure 4 This is the fourth flowchart of the one-way quantum communication method provided by the present invention;

[0057] Figure 5 This is the fifth flowchart illustrating the one-way quantum communication method provided by the present invention;

[0058] Figure 6 This is one of the structural schematic diagrams of the unidirectional quantum communication device provided by the present invention;

[0059] Figure 7 This is the second schematic diagram of the unidirectional quantum communication device provided by the present invention;

[0060] Figure 8 This is a schematic diagram of the structure of the electronic device provided by the present invention.

[0061] Figure label:

[0062] 610: Information precoding unit; 620: Key extraction unit; 630: Single-photon preparation unit; 640: Single-photon encoding and emission unit;

[0063] 710: Single-photon receiving unit; 720: Single-photon measurement unit; 730: Single-photon detection and acquisition unit; 740: Security confirmation unit; 750: Decoding unit;

[0064] 810: Processor; 820: Communication interface; 830: Memory; 840: Communication bus. Detailed Implementation

[0065] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0066] The following is combined with Figures 1-5 The present invention describes a one-way quantum communication method. Figures 1-5 This is a flowchart illustrating the one-way quantum communication method provided by the present invention, as shown below. Figure 1 As shown, the method used for the information sending end includes the following steps:

[0067] Step 110: Obtain the information to be transmitted and pre-encode it to generate a digital string to be transmitted; the digital string includes an information part and a detection part. The information sending end, Alice, obtains the information to be transmitted and processes it. Specifically, as follows... Figure 5 As shown, Alice, the information sender, uses an error-correcting encoder to pre-encode the information to be transmitted, generating a set of binary codewords. She also prepares another set of binary random numbers for eavesdropping detection. Alice randomly inserts these random numbers into the encoded information to be transmitted, and the two together form the transmitted digital string. This transmitted digital string can also be called the "information codeword-detection" digital string. In other words, the transmitted digital string includes both an information part and a detection part.

[0068] Step 120: Extract a first key and a second key of equal length to the string of numbers to be transmitted from two sets of random numbers, wherein the two sets of random numbers are pre-shared by the information sending end and the information receiving end. Figure 4 As shown, this invention relates to user terminal Alice and user terminal Bob, wherein user terminal Alice is an information transmitter used to generate and transmit single-photon qubits. User terminal Bob is an information receiver used to receive and measure single-photon qubits.

[0069] In practice, Alice, the information sender, and Bob, the information receiver, share two sets of random numbers in advance. These random numbers serve as the source of the key and are used for subsequent quantum state preparation and measurement. Specifically, Alice and Bob can distribute the random numbers using the BB84 protocol in quantum key distribution, or they can share the random numbers in advance while maintaining communication.

[0070] Next, from the two pre-shared sets of random numbers, the sending end Alice extracts two keys of the same length as the string to be transmitted, naming them the first key and the second key. It's important to note that after sharing the random numbers, the sending end Alice extracts a key of equal length from the random numbers based on the length of the string to be transmitted. The sending end Alice and the receiving end Bob only need to determine the starting position beforehand. For example, in one embodiment, the sending end Alice and the receiving end Bob determine the starting position in advance, defaulting to starting from the first position.

[0071] Step 130: Based on preset rules, single photons are prepared using the first key and the second key. Using the first key and the second key, the information transmitter Alice prepares a set of single photons, which are the quantum carriers used to encode information in this invention.

[0072] Specifically, Alice, the information sender, uses two sets of keys to prepare single photons, based on the following preset rules: the first key B is used to synchronize Alice and Bob's basis vector selection; if a bit in the first key B is 0, then they should select a basis vector.

[0073] {|H>=|0>,|V>=|1>},

[0074] Where |0> represents the horizontal state and |1> represents the vertical state; if a bit in the first key is 1, then they should choose a basis vector.

[0075]

[0076] Where |0> represents the horizontal state and |1> represents the vertical state.

[0077] The second key K is used to select the quantum state of a single photon. For example, if the i-th number in the second key K is 0, then when B... i When = 0, the quantum state of the photon is |0>, B i When =1, the quantum state of the photon is |+>.

[0078] Step 140: Encode the single photon according to the digital string to be transmitted to obtain the single photon to be transmitted, and send the single photon to be transmitted one by one to the information receiving end; the single photon to be transmitted carries the current transmission ciphertext.

[0079] The information transmitter, Alice, uses quantum unitary gates to manipulate a single photon, encoding the digital string to be transmitted onto the single photon, thus obtaining the single photon to be transmitted. Based on the prepared digital string, Alice encodes the single photon. The encoding method used here is to implement U0 = I and U1 = iσ. y Quantum gate operations correspond to the values ​​0 and 1 in a number string, respectively. Where σ... y It is the Pauli-y matrix.

[0080] The advantage of the U1 gate operation is that it only flips the quantum state within the basis vectors, that is...

[0081] U1|H>=-|V>U1|V>=|H>

[0082] U1|+>=|->U1|->=-|+>.

[0083] At this point, the encoding of the single photon is complete. Clearly, the second key K is equivalent to the key used in bidirectional quantum direct communication to encrypt information into ciphertext. It is used to encrypt the transmitted digital string S, thus obtaining the ciphertext. Ciphertext C consists of two parts: the information part, the ciphertext C of the number string M. M And detect the ciphertext C of the partial digital string R. R The currently transmitted ciphertext refers to the ciphertext C of the information string M. M .

[0084] After single-photon encoding is completed, the information sender Alice sends the single photons to be transmitted to the information receiver Bob one by one. Block transmission technology is not required during the transmission process, which means that the present invention does not require quantum storage technology.

[0085] The information transmitter of this invention acquires the information to be transmitted, pre-encodes it into a digital string, and prepares single photons based on a first key and a second key extracted from random numbers shared with the information receiver beforehand. The single photons are then encoded according to the digital string and sent to the information receiver. This invention generates and transmits single-photon qubits based on the shared keys and the information to be transmitted, avoiding the use of block transmission technology, eliminating the dependence of bidirectional protocols on quantum storage technology, and increasing practicality.

[0086] like Figure 2 As shown, the method for the information receiving end includes the following steps:

[0087] Step 210: Obtain the single photons to be transmitted from the information sender. Bob, the information receiver, receives the single photons to be transmitted one by one from Alice, the information sender.

[0088] Step 220: Using the first key distributed by the information sender, a measurement basis vector is selected to measure the received single photon to be transmitted. The measurement result is then extracted using the second key distributed by the information sender. The measurement result includes information bit values ​​and detection bit values. After receiving the single photon to be transmitted from the information sender Alice, the information receiver Bob uses the pre-shared first key to select a suitable measurement basis vector to perform the measurement operation on the photon to be transmitted, and then uses the second key to extract the measurement result. Specifically, the second key K is extracted. i The value is used to obtain the information bit value M. i and detection bit value R i .

[0089] Step 230: Obtain the position and value of the single photon used for detection from the information sending end. At this point, perform a security check on this transmission. Figure 4 As shown, the information transmitter Alice publishes the bit position and value of the detected single photon, and the information receiver obtains the position and value of the detected single photon. In one embodiment of the present invention, the information transmitter Alice publicly discloses the position and value C of the detected single photon through a classical channel. R(i)

[0090] Step 240: Compare and calculate the position and value of the single photon used for detection with the measurement results to determine the bit error rate of the current transmission.

[0091] After Bob, the information receiver, obtains the position and value of the single photon used for detection, he calculates and determines the quantum bit error rate (QBER) of this transmission by comparing the measurement results.

[0092] Step 250: If the bit error rate of the quantum bit is lower than a preset threshold, transmission continues, and the measurement result is decoded to obtain the information to be transmitted.

[0093] If the bit error rate is below a preset threshold, it indicates that the transmission channel is secure, and the sender Alice and receiver Bob can determine that no eavesdropper exists and continue the protocol; otherwise, the transmission will be discarded and restarted, a new random number will be generated and shared. In one embodiment, the preset threshold can be 11%.

[0094] The information receiving end of this invention uses a first key and a second key to measure the received single photon to be transmitted, and compares the measurement result with the position and value of the single photon to be detected disclosed by the information sending end. The calculated result is then compared with a preset threshold for security judgment. After security is confirmed, the test result is decoded to obtain the information to be transmitted. The information receiving end of this invention receives and measures single photon qubits according to a key shared with the information sending end in advance, and directly uses the single photon to be transmitted for quantum channel eavesdropping detection. The quantum state only needs to be transmitted once in the channel, resulting in less loss and a longer transmission distance.

[0095] like Figure 3 As shown, the interaction between the information sender and the information receiver includes the following steps:

[0096] Step 301: The information sending end and the information receiving end share two sets of random numbers in advance.

[0097] like Figure 4 As shown, this invention relates to user terminal Alice and user terminal Bob, wherein user terminal Alice is an information transmitter used to generate and transmit single-photon qubits. User terminal Bob is an information receiver used to receive and measure single-photon qubits.

[0098] In practice, Alice, the information sender, and Bob, the information receiver, share two sets of random numbers in advance. These random numbers serve as the source of the key and are used for subsequent quantum state preparation and measurement. Specifically, Alice and Bob can distribute the random numbers using the BB84 protocol in quantum key distribution, or they can share the random numbers in advance while maintaining communication.

[0099] Step 302: The information sending end obtains the information to be transmitted and pre-encodes the information to be transmitted to generate a digital string to be transmitted; the digital string to be transmitted includes an information part and a detection part.

[0100] The sending end, Alice, obtains the message to be transmitted and processes it. Specifically, for example... Figure 5 As shown, Alice, the information sender, uses an error-correcting encoder to pre-encode the information to be transmitted, generating a set of binary codewords. She also prepares another set of binary random numbers for eavesdropping detection. Alice randomly inserts these random numbers into the encoded information to be transmitted, and the two together form the transmitted digital string. This transmitted digital string can also be called the "information codeword-detection" digital string. In other words, the transmitted digital string includes both an information part and a detection part.

[0101] In practice, the sending end Alice converts the information to be transmitted into binary numbers {0,1}. n Then, the pre-coded information from the error correction encoder is used. Then, the information sender, Alice, randomly generates a set of length n. r A random number R is generated from -bits, and this random number is randomly inserted into the encoded codeword M to obtain a set of n. m +n r A string of numbers S of length 1 to be transmitted. This operation is for subsequent channel eavesdropping detection. For example, the information sender Alice generates a string of numbers to be transmitted, 10001100101, where the 1001011 without underscores is the preprocessed information to be transmitted, and the 1001011 with underscores is the preprocessed information to be transmitted. 0100 It is a random number used to detect the presence of an eavesdropper.

[0102] It should be noted that the length and value of the random numbers generated by Alice at the information sending end are random, but it is necessary to ensure that their quantity is sufficient to predict the bit error rate of the qubits. This invention does not impose any limitations on this.

[0103] Step 303: The information sending end extracts a first key and a second key of the same length as the number string to be transmitted from two pre-shared sets of random numbers.

[0104] From the two pre-shared sets of random numbers, Alice, the sending end, extracts two keys of the same length as the string to be transmitted, naming them the first key and the second key. It's important to note that after sharing the random numbers, Alice extracts a key of equal length from the random numbers based on the length of the string to be transmitted. Alice and Bob, the receiving end, only need to determine the starting position beforehand. For example, in one embodiment, Alice and Bob pre-determine the starting position, defaulting to the first position.

[0105] In practical operation, for example, the length of the number string S to be transmitted is n bits. m +n r Alice, the information sender, selects two sets of length n from the random numbers pre-shared in step 301. m +n r The bits of the key are named Key B (first key) and Key K (second key).

[0106] Step 304: Based on preset rules, the information sending end uses the first key and the second key to prepare a single photon.

[0107] Using the first key and the second key, the information transmitter Alice prepares a set of single photons, which is the quantum carrier used to encode information in this invention.

[0108] Specifically, Alice, the information sender, uses two sets of keys to prepare single photons, based on the following preset rules: the first key B is used to synchronize Alice and Bob's basis vector selection; if a bit in the first key B is 0, then they should select a basis vector.

[0109] {|H>=|0>,|V>=|1>},

[0110] Where |0> represents the horizontal state and |1> represents the vertical state; if a bit in the first key is 1, then they should choose a basis vector.

[0111]

[0112] Where |0> represents the horizontal state and |1> represents the vertical state.

[0113] The second key K is used to select the quantum state of a single photon. For example, if the i-th number in the second key K is 0, then when B... i When = 0, the quantum state of the photon is |0>, B i When =1, the quantum state of the photon is |+>.

[0114] Step 305: The information sending end encodes the single photon according to the digital string to be transmitted to obtain the single photon to be transmitted; the single photon to be transmitted carries the current transmission ciphertext.

[0115] The information transmitter, Alice, uses quantum unitary gates to manipulate a single photon, encoding the digital string to be transmitted onto the single photon, thus obtaining the single photon to be transmitted. Based on the prepared digital string, Alice encodes the single photon. The encoding method used here is to implement U0 = I and U1 = iσ. y Quantum gate operations correspond to the values ​​0 and 1 in a number string, respectively. Where σ... y It is the Pauli-y matrix.

[0116] The advantage of the U1 gate operation is that it only flips the quantum state within the basis vectors, that is...

[0117] U1|H>=-|V>U1|V>=|H>

[0118] U1|+>=|->U1|->=-|+>.

[0119] At this point, the encoding of the single photon is complete. Clearly, the second key K is equivalent to the key used in bidirectional quantum direct communication to encrypt information into ciphertext. It is used to encrypt the transmitted digital string S, thus obtaining the ciphertext. Ciphertext C consists of two parts: the information part, the ciphertext C of the number string M. M And detect the ciphertext C of the partial digital string R. RThe currently transmitted ciphertext refers to the ciphertext C of the information string M. M .

[0120] Step 306: The information sending end sends the single photons to be transmitted one by one to the information receiving end. After the single photon encoding is completed, the information sending end Alice sends the single photons to be transmitted one by one to the information receiving end Bob. Block transmission technology is not required during the transmission process, which means that the present invention does not require quantum storage technology.

[0121] Step 307: The information receiving end uses the first key to select the measurement basis vector to measure the received single photon to be transmitted, and uses the second key to extract the measurement result, which includes information bit value and detection bit value.

[0122] After receiving the single photon to be transmitted from the sending end Alice, Bob, the receiving end, uses the pre-shared first key to select an appropriate measurement basis vector to perform measurement operations on the photon, and then uses the second key to extract the measurement results. Specifically, the second key K is extracted. i The value is used to obtain the information bit value M. i and detection bit value R i .

[0123] Step 308: The information transmitter discloses the position and value of the single photon used for detection through a classical channel.

[0124] At this point, a security check is performed on the transmission. For example... Figure 4 As shown, the information transmitter Alice publishes the bit position and value of the detected single photon. In one embodiment of the present invention, the information transmitter Alice publicly discloses the detected single photon position and value C through a classical channel. R(i)

[0125]

[0126] Step 309: The information receiving end compares and calculates the position and value of the single photon used for detection with the measurement result to determine the bit error rate of the current transmission; if the bit error rate of the quantum bit is lower than a preset threshold, it is confirmed to be safe and the transmission continues; if the bit error rate of the quantum bit is equal to or higher than the preset threshold, the transmission is terminated and the process returns to step 301.

[0127] After Bob, the information receiver, acquires the position and value of the single photon used for detection, he calculates and determines the quantum bit error rate (QBER) of this transmission by comparing the measurement results. If the QBER is lower than a preset threshold, it indicates that the transmission channel is secure, and Alice, the information sender, and Bob, the information receiver, can determine that no eavesdropper exists and continue the protocol, jumping to step 310; otherwise, the transmission is abandoned and restarted, jumping to step 301. In one embodiment, the preset threshold can be 11%.

[0128] Step 310: After confirming security, the information receiving end decodes the measurement results to obtain the information to be transmitted. After confirming channel security, Bob at the information receiving end removes the digital string of the detection portion from the measurement results to obtain the digital string of the information portion. Then, a corresponding error correction decoder is used to decode the digital string of the information portion to obtain the information to be transmitted.

[0129] Specifically, once Alice, the information sender, publishes the location of the single photon to be detected, and Bob, the information receiver, obtains the location and value of the single photon to be detected, then Bob, the information receiver, can obtain the transmitted information bits M. i Then, Bob, at the receiving end, uses a corresponding error-correcting decoder to decode the digital string in the information part to obtain the information to be transmitted.

[0130] Step 311: The information sender and the information receiver extract two new keys from the transmitted ciphertext after removing the detection bits and put them into a shared key pool.

[0131] After receiving the information to be transmitted, Bob, the information receiver, confirms the security of the channel. Alice, the information sender, and Bob, the information receiver, extract the key from the transmitted ciphertext after removing the detection bits. They extract two new keys and put them into the "key pool" shared by Alice and Bob as new keys for the next transmission.

[0132] In other words, the ciphertext transmitted by both parties not only represents the information currently being transmitted, but can also be used to extract the key for the next round of transmission, thus ensuring the real-time nature of the key pool. For the information sender Alice, the transmitted ciphertext represents the modulo-2 sum of the information portion of the digital string to be transmitted (denoted by M) and the value of the second key (denoted by K): For Bob, the transmitted ciphertext represents the string of numbers obtained after Bob discards the corresponding values ​​from the previous single-photon measurement results, following Alice's announcement of the detection bits and the acquisition of the position and value of the detected single photon at the receiving end. It is worth noting that Alice, the sending end, publicly discloses the position and value C of the detected single photon through a classical channel. R(i) This part of the information is no longer secure, so these bits need to be discarded when extracting the key from the ciphertext. In other words, for the ciphertext... Ciphertext C consists of two parts: the information part, the ciphertext C of the number string M. M And detect the ciphertext C of the partial digital string R. R The currently transmitted ciphertext refers to the ciphertext C of the information string M. M Ciphertext extraction is only performed on the transmitted ciphertext C. M Excluding C R The privacy amplification step in subsequent processing introduces key loss, which means that the extracted key cannot be the same length as the key transmitted in this process. As long as the newly extracted key is longer than the consumed key, the real-time performance and effectiveness of the key pool can be guaranteed.

[0133] This invention successfully reduces channel loss and effectively increases transmission distance by pre-sharing keys between user terminals, and can also reduce key loss caused by one-time pad schemes, eliminating the need for quantum storage.

[0134] To address the drawbacks of bidirectional protocols, this invention provides a unidirectional quantum communication method that achieves unidirectional transmission of quantum states between users through pre-shared keys, reducing channel loss during transmission. Addressing the issue of excessive key consumption in one-time pad schemes, this invention successfully reuses keys while maintaining unconditional security. Keys that remain secure after transmission are extracted and placed in a key pool for reuse in subsequent transmissions. This invention overcomes the limitations imposed by Shannon's theorem on keys, leveraging the unique characteristics of quantum communication to significantly improve key utilization efficiency. Furthermore, this invention avoids the use of block transmission techniques during transmission, eliminating the dependence of bidirectional protocols on quantum storage technology and providing a more practical solution for direct quantum communication.

[0135] Based on the above embodiments, the method of acquiring the information to be transmitted and pre-encoding the information to be transmitted to generate a string of numbers to be transmitted specifically includes:

[0136] Obtain the information to be transmitted and convert it into a binary number string;

[0137] The binary digit string is pre-encoded using an error correction encoder to obtain an encoded digit string;

[0138] A set of random numbers is randomly generated and randomly inserted into the encoded number string to obtain the number string to be transmitted.

[0139] Specifically, Alice, the information sender, acquires the message to be transmitted and processes it. Specifically, Alice pre-encodes the message using an error-correcting encoder to generate a set of binary codewords; she also prepares another set of binary random numbers for eavesdropping detection. Alice randomly inserts these random numbers into the encoded message, and the two together form the transmitted digital string. This transmitted digital string can also be called the "information codeword-detection" digital string. In other words, the transmitted digital string includes both an information part and a detection part.

[0140] In practice, the sending end Alice converts the information to be transmitted into binary numbers {0,1}. n Then, the pre-coded information from the error correction encoder is used. Then, the information sender, Alice, randomly generates a set of length n. r A random number R is generated from -bits, and this random number is randomly inserted into the encoded codeword M to obtain a set of n. m +n r A string of numbers S of length to be transmitted. This operation is for subsequent channel eavesdropping detection. For example, the information sender Alice generates a string of numbers 10 to be transmitted. 0 0 1 10 0 1 0 1. The 1001011 without underscores represents the pre-processed information to be transmitted; the 1001011 with underscores represents the information to be transmitted. 0100 It is a random number used to detect the presence of an eavesdropper.

[0141] It should be noted that the length and value of the random numbers generated by Alice at the information sending end are random, but it is necessary to ensure that their quantity is sufficient to predict the bit error rate of the qubits. This invention does not impose any limitations on this.

[0142] Based on the above embodiments, the preset rules in this method include:

[0143] The first key is used for selecting the basis vectors between the information sending end and the information receiving end for synchronization;

[0144] The second key is used to select the quantum state of a single photon.

[0145] Specifically, Alice, the information sender, uses two sets of keys to prepare single photons, based on the following preset rules: the first key B is used to synchronize Alice and Bob's basis vector selection; if a bit in the first key B is 0, then they should select a basis vector.

[0146] {|H>=|0>,|V>=|1>},

[0147] Where |0> represents the horizontal state and |1> represents the vertical state; if a bit in the first key is 1, then they should choose a basis vector.

[0148]

[0149] Where |0> represents the horizontal state and |1> represents the vertical state.

[0150] The second key K is used to select the quantum state of a single photon. For example, if the i-th number in the second key K is 0, then when B... i When = 0, the quantum state of the photon is |0>, B i When =1, the quantum state of the photon is |+>.

[0151] Based on the above embodiments, in this method, encoding the single photon according to the digital string to be transmitted to obtain the single photon to be transmitted specifically includes:

[0152] If the value in the string of numbers to be transmitted is 0, then a quantum gate operation U0 = I is performed on the single photon;

[0153] If the value in the transmitted digital string is 1, then U1 = iσ is applied to the single photon. y Quantum gate operations, where σ y It is the Pauli-y matrix.

[0154] Specifically, the information transmitter Alice uses quantum unitary gate operations on a single photon to encode the digital string to be transmitted onto the single photon, thus obtaining the single photon to be transmitted. Based on the prepared digital string, the information transmitter Alice encodes the single photon. The encoding method here is to implement U0 = I and U1 = iσ. y Quantum gate operations correspond to the values ​​0 and 1 in a number string, respectively. Where σ... y It is the Pauli-y matrix.

[0155] The advantage of the U1 gate operation is that it only flips the quantum state within the basis vectors, that is...

[0156] U1|H>=-|V>U1|V>=|H>

[0157] U1|+>=|->U1|->=-|+>.

[0158] At this point, the encoding of the single photon is complete. Clearly, the second key K is equivalent to the key used in bidirectional quantum direct communication to encrypt information into ciphertext. It is used to encrypt the transmitted digital string S, thus obtaining the ciphertext. Ciphertext C consists of two parts: the information part, the ciphertext C of the number string M.M And detect the ciphertext C of the partial digital string R. R The currently transmitted ciphertext refers to the ciphertext C of the information string M. M .

[0159] Based on the above embodiments, the method specifically includes the transmission of ciphertext as follows:

[0160] The information portion of the digital string to be transmitted is modulo 2 sum of the second key value.

[0161] Specifically, after Bob, the information receiver, receives the information to be transmitted, the security of the channel is confirmed. Alice, the information sender, and Bob, the information receiver, extract the key from the transmitted ciphertext after removing the detection bits, extract two new keys, and put them into the "key pool" jointly owned by Alice and Bob as new keys for the next transmission.

[0162] In other words, the ciphertext transmitted by both parties not only represents the information currently being transmitted, but can also be used to extract the key for the next round of transmission, thus ensuring the real-time nature of the key pool. For the information sender Alice, the transmitted ciphertext represents the modulo-2 sum of the information portion of the digital string to be transmitted (denoted by M) and the value of the second key (denoted by K): It is worth noting that, because the information transmitter Alice publicly disclosed the location and numerical value C of the detected single photon through a classical channel... R(i) This part of the information is no longer secure, so these bits need to be discarded when extracting the key from the ciphertext. In other words, for the ciphertext... Ciphertext C consists of two parts: the information part, the ciphertext C of the number string M. M And detect the ciphertext C of the partial digital string R. R The currently transmitted ciphertext refers to the ciphertext C of the information string M. M Ciphertext extraction is only performed on the transmitted ciphertext C. M Excluding C R The privacy amplification step in subsequent processing introduces key loss, which means that the extracted key cannot be the same length as the key transmitted in this process. As long as the newly extracted key is longer than the consumed key, the real-time performance and effectiveness of the key pool can be guaranteed.

[0163] Based on the above embodiments, in this method, decoding the measurement results to obtain the information to be transmitted specifically includes:

[0164] The detection portion is removed from the measurement results to obtain the information measurement results;

[0165] The information measurement results are decoded using an error correction decoder to obtain the information to be transmitted;

[0166] The detection section includes the position and value of the single photon obtained from the information transmitting end for detection.

[0167] Specifically, after confirming channel security, Bob at the information receiving end removes the digital string from the detection portion of the measurement result to obtain the digital string for the information portion. Then, a corresponding error-correcting decoder decodes the digital string for the information portion to obtain the information to be transmitted.

[0168] Specifically, once Alice, the information sender, publishes the location of the single photon to be detected, and Bob, the information receiver, obtains the location and value of the single photon to be detected, then Bob, the information receiver, can obtain the transmitted information bits M. i Then, Bob, at the receiving end, uses a corresponding error-correcting decoder to decode the digital string in the information part to obtain the information to be transmitted.

[0169] Based on the above embodiments, in this method, the position and value of the single photon used for detection are compared and calculated with the measurement result to determine the bit error rate of the current transmission, and then the method further includes:

[0170] If the bit error rate of the quantum bit is equal to or higher than a preset threshold, then the transmission is terminated and the random number is reset; and / or,

[0171] Two new keys are extracted from the transmitted ciphertext after removing the detection bits and stored in a shared key pool.

[0172] Specifically, after Bob, the information receiver, acquires the position and value of the single photon used for detection, he calculates and determines the quantum bit error rate (QBER) of this transmission by comparing the measurement results. If the QBER is lower than a preset threshold, it indicates that the transmission channel is secure, and Alice, the information sender, and Bob, the information receiver, can determine that no eavesdropper exists and continue the protocol; otherwise, the transmission will be discarded and restarted, with new random numbers generated and shared. In one embodiment, the preset threshold can be 11%.

[0173] After receiving the information to be transmitted, Bob, the information receiver, confirms the security of the channel. Alice, the information sender, and Bob, the information receiver, extract the key from the transmitted ciphertext after removing the detection bits. They extract two new keys and put them into the "key pool" shared by Alice and Bob as new keys for the next transmission.

[0174] In other words, the ciphertext transmitted by both parties not only represents the information currently being transmitted, but can also be used to extract the key for the next round of transmission, thus ensuring the real-time nature of the key pool. For the information sender Alice, the transmitted ciphertext represents the modulo-2 sum of the information portion of the digital string to be transmitted (denoted by M) and the value of the second key (denoted by K): For Bob, the transmitted ciphertext represents the string of numbers obtained after Bob discards the corresponding values ​​from the previous single-photon measurement results, following Alice's announcement of the detection bits and the acquisition of the position and value of the detected single photon at the receiving end. It is worth noting that Alice, the sending end, publicly discloses the position and value C of the detected single photon through a classical channel. R(i) This part of the information is no longer secure, so these bits need to be discarded when extracting the key from the ciphertext. In other words, for the ciphertext... Ciphertext C consists of two parts: the information part, the ciphertext C of the number string M. M And detect the ciphertext C of the partial digital string R. R The currently transmitted ciphertext refers to the ciphertext C of the information string M. M Ciphertext extraction is only performed on the transmitted ciphertext C. M Excluding C R The privacy amplification step in subsequent processing introduces key loss, which means that the extracted key cannot be the same length as the key transmitted in this process. As long as the newly extracted key is longer than the consumed key, the real-time performance and effectiveness of the key pool can be guaranteed.

[0175] Based on the above embodiments, the method specifically includes the transmission of ciphertext as follows:

[0176] After obtaining the position and value of the single photon used for detection from the information sending end, the numerical string obtained by discarding the corresponding values ​​of the measurement result.

[0177] Specifically, after Bob, the information receiver, receives the information to be transmitted, the security of the channel is confirmed. Alice, the information sender, and Bob, the information receiver, extract the key from the transmitted ciphertext after removing the detection bits, extract two new keys, and put them into the "key pool" jointly owned by Alice and Bob as new keys for the next transmission.

[0178] In other words, the ciphertext transmitted by both parties not only represents the information currently being transmitted, but can also be used to extract the key for the next round of transmission, thus ensuring the real-time nature of the key pool. For Bob, the transmitted ciphertext represents the string of numbers obtained in step 230 after Bob discards the corresponding values ​​from the single-photon measurement results of the previous step, after acquiring the position and value of the single photon used for detection at the information receiving end. It is worth noting that since Alice, the information sending end, publicly discloses the position and value C of the detected single photon through a classical channel... R(i) This part of the information is no longer secure, so these bits need to be discarded when extracting the key from the ciphertext. In other words, for the ciphertext... Ciphertext C consists of two parts: the information part, the ciphertext C of the number string M. M And detect the ciphertext C of the partial digital string R. R The currently transmitted ciphertext refers to the ciphertext C of the information string M. M Ciphertext extraction is only performed on the transmitted ciphertext C. M Excluding C R The privacy amplification step in subsequent processing introduces key loss, which means that the extracted key cannot be the same length as the key transmitted in this process. As long as the newly extracted key is longer than the consumed key, the real-time performance and effectiveness of the key pool can be guaranteed.

[0179] This invention provides a one-way quantum communication method. The method for an information transmitter includes: acquiring information to be transmitted and pre-encoding the information to generate a digital string to be transmitted; the digital string to be transmitted includes an information portion and a detection portion; extracting a first key and a second key of equal length to the digital string to be transmitted from two sets of random numbers, wherein the two sets of random numbers are pre-shared by the information transmitter and the information receiver; preparing single photons based on preset rules using the first key and the second key; encoding the single photons according to the digital string to be transmitted to obtain single photons to be transmitted, and transmitting the single photons to be transmitted one by one to the information receiver; the single photons to be transmitted carry the currently transmitted ciphertext. The method for an information receiving end includes: acquiring a single photon to be transmitted from an information sending end; selecting a measurement basis vector using a first key distributed by the information sending end to measure the received single photon to be transmitted, and extracting the measurement result using a second key distributed by the information sending end to obtain a measurement result, the measurement result including an information bit value and a detection bit value; acquiring the position and value of a single photon to be detected obtained by the information sending end; comparing and calculating the position and value of the single photon to be detected with the measurement result to determine the qubit error rate of this transmission; if the qubit error rate is lower than a preset threshold, continuing transmission, and decoding the measurement result to obtain the information to be transmitted. The information sending end of this invention acquires the information to be transmitted, pre-encodes the information into a digital string to be transmitted, prepares a single photon based on a first key and a second key extracted from a random number shared with the information receiving end in advance, encodes the single photon according to the digital string to be transmitted, and sends the encoded single photon to be transmitted to the information receiving end. The information transmitting end of this invention generates and transmits single-photon qubits based on a key shared in advance with the information receiving end and the information to be transmitted, avoiding the use of block transmission technology, eliminating the dependence of bidirectional protocols on quantum storage technology, and increasing practicality.

[0180] The information receiving end of this invention uses a first key and a second key to measure the received single photon to be transmitted, and compares the measurement result with the position and value of the single photon to be detected disclosed by the information sending end. The calculated result is then compared with a preset threshold for security judgment. After security is confirmed, the test result is decoded to obtain the information to be transmitted. The information receiving end of this invention receives and measures single photon qubits according to a key shared with the information sending end in advance, and directly uses the single photon to be transmitted for quantum channel eavesdropping detection. The quantum state only needs to be transmitted once in the channel, resulting in less loss and a longer transmission distance.

[0181] This invention first pre-shares a key between user terminals. The sending end prepares a single photon based on this key and encodes the information to be transmitted onto the single photon's quantum state. Then, it sends the encoded single photon to the receiving end through a quantum channel. Upon receiving the encoded single photon, the receiving end uses the transmitted single photon to perform eavesdropping detection on the quantum channel to confirm its security. Finally, it uses the pre-shared key to read the single photon information, completing the information transmission. The quantum direct communication method provided by this invention requires the quantum state to be transmitted only once in the channel, resulting in less loss, longer transmission distance, and eliminating the need for block transmission technology. This also eliminates the dependence of bidirectional protocols on quantum storage technology, making it more practical.

[0182] The following describes the one-way quantum communication method and apparatus provided by the present invention. The one-way quantum communication method and apparatus described below can be referred to in correspondence with the one-way quantum communication method described above.

[0183] Figure 6 This is one of the structural schematic diagrams of the unidirectional quantum communication device provided by the present invention, such as... Figure 6 As shown, the information transmitting end includes an information precoding unit 610, a key interception unit 620, a single-photon preparation unit 630, and a single-photon encoding and transmission unit 640.

[0184] in,

[0185] The information precoding unit 610 is used to acquire information to be transmitted and precode the information to be transmitted to generate a digital string to be transmitted; the digital string to be transmitted includes an information part and a detection part.

[0186] The key extraction unit 620 is used to extract a first key and a second key of the same length as the digital string to be transmitted from two sets of random numbers, wherein the two sets of random numbers are shared in advance by the information sending end and the information receiving end;

[0187] The single-photon preparation unit 630 is used to prepare a single photon based on a preset rule using the first key and the second key.

[0188] The single-photon encoding and transmitting unit 640 is used to encode the single photon according to the digital string to be transmitted to obtain the single photon to be transmitted, and to send the single photon to be transmitted one by one to the information receiving end; the single photon to be transmitted carries the current transmission ciphertext.

[0189] Based on the above embodiments, in this device, acquiring the information to be transmitted and pre-encoding the information to be transmitted to generate a string of numbers to be transmitted specifically includes:

[0190] Obtain the information to be transmitted and convert it into a binary number string;

[0191] The binary digit string is pre-encoded using an error correction encoder to obtain an encoded digit string;

[0192] A set of random numbers is randomly generated and randomly inserted into the encoded number string to obtain the number string to be transmitted.

[0193] Based on the above embodiments, the preset rules in this device include:

[0194] The first key is used for selecting the basis vectors between the information sending end and the information receiving end for synchronization;

[0195] The second key is used to select the quantum state of a single photon.

[0196] Based on the above embodiments, in this device, encoding the single photon according to the digital string to be transmitted to obtain the single photon to be transmitted specifically includes:

[0197] If the value in the string of numbers to be transmitted is 0, then a quantum gate operation U0 = I is performed on the single photon;

[0198] If the value in the transmitted digital string is 1, then U1 = iσ is applied to the single photon. y Quantum gate operations, where σ y It is the Pauli-y matrix.

[0199] Based on the above embodiments, in this device, the transmitted encrypted text specifically includes:

[0200] The information portion of the digital string to be transmitted is modulo 2 sum of the second key value.

[0201] The following describes the one-way quantum communication method and apparatus provided by the present invention. The one-way quantum communication method and apparatus described below can be referred to in correspondence with the one-way quantum communication method described above.

[0202] Figure 7 This is a second schematic diagram of the unidirectional quantum communication device provided by the present invention, as shown below. Figure 7 As shown, the information receiving end includes a single-photon receiving unit 710, a single-photon measurement unit 720, a single-photon detection and acquisition unit 730, a security confirmation unit 740, and a decoding unit 750.

[0203] in,

[0204] The single-photon receiving unit 710 is used to acquire the single photon to be transmitted by the information sending end;

[0205] The single-photon measurement unit 720 is used to select a measurement basis vector using a first key distributed by the information transmitter to measure the received single photon to be transmitted, and to extract the measurement result using a second key distributed by the information transmitter to obtain the measurement result, which includes information bit value and detection bit value.

[0206] The single-photon detection acquisition unit 730 is used to acquire the position and value of the single photon to be detected obtained by the information transmitting end;

[0207] The security verification unit 740 is used to compare and calculate the position and value of the detected single photon with the measurement result to determine the bit error rate of the current transmission of qubits;

[0208] The decoding unit 750 is used to continue transmission if the bit error rate of the qubit is lower than a preset threshold, and to decode the measurement result to obtain the information to be transmitted.

[0209] Based on the above embodiments, in this device, the measurement results are decoded to obtain the information to be transmitted, specifically including:

[0210] The detection portion is removed from the measurement results to obtain the information measurement results;

[0211] The information measurement results are decoded using an error correction decoder to obtain the information to be transmitted;

[0212] The detection section includes the position and value of the single photon obtained from the information transmitting end for detection.

[0213] Based on the above embodiments, in this device, the position and value of the single photon used for detection are compared and calculated with the measurement result to determine the bit error rate of the current transmission, and then the device further includes:

[0214] If the bit error rate of the quantum bit is equal to or higher than a preset threshold, then the transmission is terminated and the random number is reset; and / or,

[0215] Two new keys are extracted from the transmitted ciphertext after removing the detection bits and stored in a shared key pool.

[0216] Based on the above embodiments, in this device, the transmitted encrypted text specifically includes:

[0217] After obtaining the position and value of the single photon used for detection from the information sending end, the numerical string obtained by discarding the corresponding values ​​of the measurement result.

[0218] This invention provides a one-way quantum communication device. The device for the information sending end includes: an information precoding unit for acquiring information to be transmitted and precoding the information to generate a digital string to be transmitted; the digital string to be transmitted includes an information portion and a detection portion; a key extraction unit for extracting a first key and a second key of equal length to the digital string to be transmitted from two sets of random numbers, wherein the two sets of random numbers are pre-shared by the information sending end and the information receiving end; a single-photon preparation unit for preparing single photons based on preset rules using the first key and the second key; and a single-photon encoding and transmission unit for encoding the single photons according to the digital string to be transmitted to obtain single photons to be transmitted, and transmitting the single photons to be transmitted one by one to the information receiving end; the single photons to be transmitted carry the currently transmitted ciphertext. The apparatus for the information receiving end includes: a single-photon receiving unit for acquiring a single photon to be transmitted from the information sending end; a single-photon measurement unit for selecting a measurement basis vector using a first key distributed by the information sending end to measure the received single photon to be transmitted, and extracting the measurement result using a second key distributed by the information sending end, the measurement result including an information bit value and a detection bit value; a single-photon detection acquisition unit for acquiring the position and value of the single photon to be detected obtained by the information sending end; a security confirmation unit for comparing and calculating the position and value of the single photon to be detected with the measurement result to determine the qubit error rate of this transmission; and a decoding unit for continuing transmission if the qubit error rate is lower than a preset threshold, and decoding the measurement result to obtain the information to be transmitted. The information transmitter of this invention acquires the information to be transmitted, pre-encodes it into a digital string, and prepares single photons based on a first key and a second key extracted from random numbers shared with the information receiver beforehand. The single photons are then encoded according to the digital string and sent to the information receiver. This invention generates and transmits single-photon qubits based on the shared keys and the information to be transmitted, avoiding the use of block transmission technology, eliminating the dependence of bidirectional protocols on quantum storage technology, and increasing practicality.

[0219] The information receiving end of this invention uses a first key and a second key to measure the received single photon to be transmitted, and compares the measurement result with the position and value of the single photon to be detected disclosed by the information sending end. The calculated result is then compared with a preset threshold for security judgment. After security is confirmed, the test result is decoded to obtain the information to be transmitted. The information receiving end of this invention receives and measures single photon qubits according to a key shared with the information sending end in advance, and directly uses the single photon to be transmitted for quantum channel eavesdropping detection. The quantum state only needs to be transmitted once in the channel, resulting in less loss and a longer transmission distance.

[0220] This invention first pre-shares a key between user terminals. The sending end prepares a single photon based on this key and encodes the information to be transmitted onto the single photon's quantum state. Then, it sends the encoded single photon to the receiving end through a quantum channel. Upon receiving the encoded single photon, the receiving end uses the transmitted single photon to perform eavesdropping detection on the quantum channel to confirm its security. Finally, it uses the pre-shared key to read the single photon information, completing the information transmission. The quantum direct communication method provided by this invention requires the quantum state to be transmitted only once in the channel, resulting in less loss, longer transmission distance, and eliminating the need for block transmission technology. This also eliminates the dependence of bidirectional protocols on quantum storage technology, making it more practical.

[0221] Figure 8 An example is a schematic diagram of the physical structure of an electronic device, such as... Figure 8 As shown, the electronic device may include: a processor 810, a communication interface 820, a memory 830, and a communication bus 840, wherein the processor 810, the communication interface 820, and the memory 830 communicate with each other through the communication bus 840. The processor 810 can call logic instructions in the memory 830 to execute a one-way quantum communication method. This method includes: a method for the information sender including: acquiring information to be transmitted and pre-encoding the information to generate a digital string to be transmitted; the digital string to be transmitted includes an information portion and a detection portion; extracting a first key and a second key of equal length to the digital string to be transmitted from two sets of random numbers, wherein the two sets of random numbers are pre-shared by the information sender and the information receiver; preparing a single photon based on a preset rule using the first key and the second key; encoding the single photon according to the digital string to be transmitted to obtain a single photon to be transmitted, and sending the single photon to be transmitted one by one to the information receiver; the single photon to be transmitted carries the currently transmitted ciphertext. The method for an information receiving end includes: acquiring a single photon to be transmitted from an information sending end; selecting a measurement basis vector using a first key distributed by the information sending end to measure the received single photon to be transmitted, and extracting the measurement result using a second key distributed by the information sending end to obtain a measurement result, the measurement result including an information bit value and a detection bit value; acquiring the position and value of a single photon to be detected obtained by the information sending end; comparing and calculating the position and value of the single photon to be detected with the measurement result to determine the qubit error rate of this transmission; if the qubit error rate is lower than a preset threshold, continuing transmission, and decoding the measurement result to obtain the information to be transmitted.

[0222] Furthermore, the logical instructions in the aforementioned memory 830 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, essentially, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0223] In another aspect, the present invention also provides a non-transitory computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the unidirectional transmission quantum communication method provided by the above methods. The method includes: a method for an information transmitter comprising: acquiring information to be transmitted and pre-encoding the information to be transmitted to generate a digital string to be transmitted; the digital string to be transmitted includes an information portion and a detection portion; extracting a first key and a second key of equal length to the digital string to be transmitted from two sets of random numbers, wherein the two sets of random numbers are pre-shared by the information transmitter and the information receiver; preparing a single photon based on a preset rule using the first key and the second key; encoding the single photon according to the digital string to be transmitted to obtain a single photon to be transmitted, and transmitting the single photon to be transmitted one by one to the information receiver; the single photon to be transmitted carries the currently transmitted ciphertext. The method for an information receiving end includes: acquiring a single photon to be transmitted from an information sending end; selecting a measurement basis vector using a first key distributed by the information sending end to measure the received single photon to be transmitted, and extracting the measurement result using a second key distributed by the information sending end to obtain a measurement result, the measurement result including an information bit value and a detection bit value; acquiring the position and value of a single photon to be detected obtained by the information sending end; comparing and calculating the position and value of the single photon to be detected with the measurement result to determine the qubit error rate of this transmission; if the qubit error rate is lower than a preset threshold, continuing transmission, and decoding the measurement result to obtain the information to be transmitted.

[0224] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0225] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0226] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A one-way quantum communication method for use at the information transmitting end, characterized in that, include: Obtain the information to be transmitted and pre-encode the information to be transmitted to generate a string of numbers to be transmitted; The digital string to be transmitted includes an information part and a detection part; A first key and a second key of the same length as the data string to be transmitted are extracted from two sets of random numbers, wherein the two sets of random numbers are shared in advance by the information sending end and the information receiving end; Based on preset rules, a single photon is prepared using the first key and the second key; the preset rules include: the first key is used for the basis vector selection of the information sending end and the information receiving end for synchronization; the second key is used for selecting the quantum state of the single photon; The single photon is encoded according to the digital string to be transmitted to obtain the single photon to be transmitted, and the single photon to be transmitted is sent to the information receiving end one by one; the single photon to be transmitted carries the current transmission ciphertext.

2. The unidirectional quantum communication method according to claim 1, characterized in that, Obtain the information to be transmitted and pre-encode the information to be transmitted to generate a string of numbers to be transmitted, specifically including: Obtain the information to be transmitted and convert it into a binary number string; The binary digit string is pre-encoded using an error correction encoder to obtain an encoded digit string; A set of random numbers is randomly generated and randomly inserted into the encoded number string to obtain the number string to be transmitted.

3. The unidirectional quantum communication method according to claim 1, characterized in that, The single photon is encoded according to the digital string to be transmitted to obtain the single photon to be transmitted, specifically including: If the value in the string of numbers to be transmitted is 0, then the single photon is subjected to... Quantum gate operations; If the value in the transmitted digital string is 1, then the single photon is subjected to... Quantum gate operations, in which, It is the Pauli-y matrix.

4. The unidirectional quantum communication method according to claim 1, characterized in that, The transmitted ciphertext specifically includes: The information portion of the digital string to be transmitted is modulo 2 sum of the second key value.

5. A one-way quantum communication method for use at an information receiving end, characterized in that, include: Acquire the single photon to be transmitted transmitted by the information sending end; the single photon to be transmitted carries the currently transmitted ciphertext; The first key distributed by the information sending end is used to select the measurement basis vector to measure the received single photon to be transmitted, and the second key distributed by the information sending end is used to extract the measurement result, which includes information bit value and detection bit value. Obtain the position and value of the single photon used for detection from the information transmitting end; The position and value of the single photon used for detection are compared with the measurement results to calculate the bit error rate of the current transmission. If the bit error rate of the quantum bit is lower than a preset threshold, transmission continues, and the measurement result is decoded to obtain the information to be transmitted.

6. The one-way quantum communication method according to claim 5, characterized in that, The measurement results are decoded to obtain the information to be transmitted, specifically including: The detection portion is removed from the measurement results to obtain the information measurement results; The information measurement results are decoded using an error correction decoder to obtain the information to be transmitted; The detection section includes the position and value of the single photon obtained from the information transmitting end for detection.

7. The one-way quantum communication method according to claim 5, characterized in that, The position and value of the single photon used for detection are compared with the measurement results to calculate the bit error rate of the current transmission, which then includes: If the bit error rate of the quantum bit is equal to or higher than a preset threshold, then the transmission is terminated and the random number is reset; and / or, Two new keys are extracted from the transmitted ciphertext after removing the detection bits and stored in a shared key pool.

8. The one-way quantum communication method according to claim 5, characterized in that, The transmitted ciphertext specifically includes: After obtaining the position and value of the single photon used for detection from the information sending end, the numerical string obtained by discarding the corresponding values ​​of the measurement result.

9. A one-way quantum communication device for use as an information transmitting end, characterized in that, include: An information precoding unit is used to acquire information to be transmitted and precode the information to be transmitted to generate a digital string to be transmitted. The digital string to be transmitted includes an information part and a detection part; A key extraction unit is used to extract a first key and a second key of the same length as the data string to be transmitted from two sets of random numbers, wherein the two sets of random numbers are shared in advance by the information sending end and the information receiving end; A single-photon preparation unit is used to prepare a single photon based on a preset rule using a first key and a second key; the preset rule includes: the first key is used to select the basis vectors of the information sending end and the information receiving end for synchronization; the second key is used to select the quantum state of the single photon; A single-photon encoding and transmitting unit is used to encode the single photon according to the digital string to be transmitted to obtain the single photon to be transmitted, and to send the single photon to be transmitted one by one to the information receiving end; the single photon to be transmitted carries the current transmission ciphertext.

10. A one-way quantum communication device for use as an information receiving end, characterized in that, include: A single-photon receiving unit is used to acquire a single photon to be transmitted from an information sending end; the single photon to be transmitted carries the currently transmitted ciphertext. A single-photon measurement unit is used to select a measurement basis vector using a first key distributed by the information transmitter to measure the received single photon to be transmitted, and to extract the measurement result using a second key distributed by the information transmitter to obtain the measurement result, which includes information bit value and detection bit value. A single-photon detection acquisition unit is used to acquire the position and value of the single photon to be detected obtained from the information transmitting end; The security verification unit is used to compare and calculate the position and value of the single photon used for detection with the measurement result to determine the bit error rate of the current transmission. The decoding unit is used to continue transmission if the bit error rate of the qubit is lower than a preset threshold, and to decode the measurement result to obtain the information to be transmitted.

11. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the one-way quantum communication method as described in any one of claims 1 to 8.

12. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the one-way quantum communication method as described in any one of claims 1 to 8.

Images