Quantum direct communication method, device, electronic device and storage medium

Abstract

The present invention provides a quantum direct communication method, device, electronic device, and storage medium, relating to the field of quantum communication technology. The method comprises: during target communication with a second communication terminal, sending a first photon sequence to a third-party device, the first photon sequence comprising multiple first optical pulse signals, each of which comprises multiple coherent states having random light intensities and random phases; obtaining a signal measurement result sent by the third-party device; and obtaining channel parameters based on the signal measurement result, a first signal parameter corresponding to the first photon sequence, and a second signal parameter number corresponding to the second photon sequence. By using the photon sequence sent by the communicating party containing coherent states of multiple intensities and random phases, the channel parameters can be obtained, thereby monitoring the channel conditions of the target communication, further avoiding photon number splitting attacks and reducing the attenuation of optical signals in the communication link.

Description

Technical Field

[0001] The present invention relates to the field of quantum communication technology, and in particular to a quantum direct communication method, device, electronic equipment and storage medium. Background Art

[0002] Quantum secure communication boasts high security guaranteed by the principles of quantum mechanics and primarily encompasses technologies such as quantum key distribution (QKD), quantum direct communication (QSDC), and quantum secret sharing (QSS). Quantum direct communication directly transmits secret information over a quantum channel, eliminating the need for pre-distribution of keys between legitimate communicating parties. This simplifies communication architecture and management costs, and offers compatibility with existing optical communication networks. It represents a new paradigm for quantum secure communication. Because flaws in actual measurement equipment can lead to security vulnerabilities, device-independent quantum direct communication protocols have been proposed. By sending quantum states to an untrusted third party for measurement and publishing the results, legitimate communicating parties mitigate vulnerabilities in their own measurement equipment.

[0003] However, in measurement-device-independent quantum direct communication, the photon number splitting attack makes the multi-photon components in the optical pulse no longer safe and increases the channel attenuation of quantum direct communication. Summary of the Invention

[0004] The present invention provides a quantum direct communication method, device, electronic device and storage medium to address the defect in the prior art that photon number splitting attacks lead to a reduction in secure channel capacity. By using the coherent state of multiple random intensities in the photon sequence sent by the communicating party, channel parameters can be obtained, thereby monitoring the channel status of the target communication, further avoiding photon number splitting attacks and reducing the attenuation of optical signals in the communication link.

[0005] The present invention provides a quantum direct communication method, comprising the following steps:

[0006] During target communication with the second communication terminal, a first photon sequence is sent to a third-party device, where the first photon sequence includes a plurality of first optical pulse signals, each of the first optical pulse signals includes a plurality of coherent states having random light intensities and random phases, and the target communication is used to indicate measurement device-independent quantum direct communication;

[0007] Obtaining a signal measurement result sent by the third-party device, the signal measurement result including a measurement result of the first photon sequence and a second photon sequence, where the second photon sequence is sent by the second communication terminal to the third-party device, the second photon sequence including a plurality of second optical pulse signals, the plurality of second optical pulse signals corresponding to transmission times of the plurality of first optical pulse signals, and each second optical pulse signal including a plurality of coherent states having random light intensities and random phases;

[0008] Channel parameters are obtained based on the signal measurement results, the first signal parameters corresponding to the first photon sequence, and the second signal parameter number corresponding to the second photon sequence. The channel parameters are used to characterize the channel conditions of the target communication. The first signal parameters and the second signal parameters both include corresponding random light intensity parameters and random phase parameters. The second signal parameters are sent by the second communication terminal to the first communication terminal.

[0009] According to a quantum direct communication method provided by the present invention, the first photon sequence further includes a plurality of third optical pulse signals, and the plurality of third optical pulse signals are used for performing the target communication. During the target communication with the second communication terminal, sending the first photon sequence to the third-party device includes:

[0010] In the process of sending the first photon sequence to the third-party device, determining, according to a preset selection probability, whether the coding mode corresponding to each optical pulse signal in the first photon sequence is the first mode or the second mode;

[0011] When determining that the encoding mode is the first mode, sending the third optical pulse signal to the third-party device;

[0012] When it is determined that the encoding mode is the second mode, the first optical pulse signal is sent to the third-party device.

[0013] According to a quantum direct communication method provided by the present invention, the first communication terminal is an information sending end of the target communication. In the process of sending the first photon sequence to the third-party device, before determining, according to a preset selection probability, whether the coding mode corresponding to each optical pulse signal in the first photon sequence is the first mode or the second mode, the method further includes:

[0014] Encode and encrypt the plaintext to be transmitted to obtain the ciphertext to be transmitted;

[0015] Performing encoding and masking capacity-increasing processing on a portion of the ciphertext to be transmitted to obtain a target ciphertext, wherein the portion of the ciphertext is a frame of ciphertext in the ciphertext to be transmitted;

[0016] The sending the third optical pulse signal to the third-party device includes:

[0017] Obtaining a target number of coherent states having the same basis vector according to the logical bits of the target ciphertext, wherein the target number of coherent states having the same basis vector is the third optical pulse signal;

[0018] The target number of coherent states having the same basis vector is sent to the third-party device.

[0019] According to a quantum direct communication method provided by the present invention, the first communication terminal is an information receiving end of the target communication, and the sending of the third optical pulse signal to the third-party device includes:

[0020] Get random bits;

[0021] Obtaining a target number of coherent states with different basis vectors according to the random bits, wherein the target number of coherent states with different basis vectors is the third optical pulse signal;

[0022] The target number of coherent states with different basis vectors is sent to the third-party device.

[0023] According to a quantum direct communication method provided by the present invention, sending the first optical pulse signal to the third-party device includes:

[0024] Acquire a random light intensity and a random phase, wherein the random light intensity falls within a preset light intensity range, and the random phase falls within a preset phase range;

[0025] Obtaining a target number of coherent states with random light intensity and random phase according to the random light intensity and the random phase, wherein the target number of coherent states with random light intensity and random phase are the first optical pulse signals;

[0026] The target number of coherent states with random light intensity and random phase are sent to the third-party device.

[0027] According to a quantum direct communication method provided by the present invention, the second photon sequence includes a plurality of fourth optical pulse signals, the plurality of fourth optical pulse signals corresponding to the plurality of third optical pulse signals, and used for the target communication. Obtaining the channel parameter based on the signal measurement result, a first signal parameter corresponding to the first photon sequence, and a second signal parameter corresponding to the second photon sequence includes:

[0028] screening the plurality of first optical pulse signals, the plurality of second optical pulse signals, the plurality of third optical pulse signals, and the plurality of fourth optical pulse signals according to the signal measurement result to obtain a plurality of roughly screened signal pairs, wherein a measurement result corresponding to each of the roughly screened signal pairs is that only one detector of the third-party device responds;

[0029] The main channel capacity and the patching channel capacity of the target communication are determined according to the multiple coarse-screened signal pairs, and the main channel capacity and the patching channel capacity are the channel parameters.

[0030] According to a quantum direct communication method provided by the present invention, the second signal parameter further includes coding patterns corresponding to the plurality of second optical pulse signals, and coding patterns and basis vector information corresponding to the plurality of fourth optical pulse signals. Determining the main channel capacity and the bridge channel capacity of the target communication based on the plurality of coarsely screened signal pairs includes:

[0031] The multiple coarse-screened signal pairs are screened according to the first signal parameter and the second signal parameter to obtain multiple fine-screened signal pairs, wherein the two optical pulse signals of the first signal pair in the multiple fine-screened signal pairs have the same coding mode, the same random optical intensity parameter, and a phase difference of the random phase parameter is 0 or π, and the two optical pulse signals of the second signal pair in the fine-screened signal pairs have the same coding mode and basis vector information, the first signal parameter includes the coding mode, random optical intensity parameter, and random phase parameter corresponding to the multiple first optical pulse signals, and the coding mode and basis vector information corresponding to the multiple third optical pulse signals, the first signal pair is an optical pulse signal pair whose coding mode is the second mode, and the second signal pair is an optical pulse signal pair whose coding mode is the first mode;

[0032] determining a bonding channel capacity for the target communication based on a plurality of first signal pairs among the finely screened signal pairs;

[0033] The main channel capacity of the target communication is determined according to a plurality of second signal pairs in the finely screened signal pairs.

[0034] According to a quantum direct communication method provided by the present invention, the channel parameters include the wiring channel capacity and the main channel capacity, and the encoding and encryption processing of the plaintext to be transmitted to obtain the ciphertext to be transmitted includes:

[0035] Encrypting the plaintext to be transmitted using a first key to obtain a first intermediate ciphertext, where the first key is a key obtained from a shared key pool;

[0036] Encoding the first intermediate ciphertext using a first encoder to obtain the ciphertext to be transmitted, wherein the ciphertext to be transmitted is stored in a first cache, and the first encoder is an error correction code encoder;

[0037] The encoding and masking of part of the ciphertext to be transmitted to obtain target ciphertext includes:

[0038] Retrieving a ciphertext sequence of a target length from the first buffer to obtain the partial ciphertext;

[0039] Encoding the partial ciphertext using a second encoder to obtain a third intermediate ciphertext, wherein the security coding rate of the second encoder is a target value, and the length of the third intermediate ciphertext is a reference length;

[0040] performing masked multiplication on the third intermediate ciphertext and a first random sequence to obtain the target ciphertext, where the first random sequence is obtained through a random number generator;

[0041] The target value and the target length are determined based on the main channel capacity of the previous frame, the wiring channel capacity of the previous frame, and safety communication limitation conditions obtained during the transmission of the previous frame optical pulse signal. The safety communication limitation conditions include that the first value is less than or equal to the second value, and the target value is less than the main channel capacity of the previous frame. The first value is the quotient of the target length and the reference length, and the second value is the difference between the target value and the wiring channel capacity of the previous frame.

[0042] According to a quantum direct communication method provided by the present invention, the method further includes:

[0043] When the capacity of the main channel and the capacity of the bonding channel meet the secure communication restriction condition, extracting the target shared key from the shared key pool for encoding the next frame of optical pulses;

[0044] The first random sequence is sent to the second communication terminal.

[0045] According to a quantum direct communication method provided by the present invention, the first communication terminal is an information receiving end of the target communication, and the method further includes:

[0046] Obtaining a second random sequence sent by the second communication terminal;

[0047] Perform reverse masking and capacitation on the second random sequence and the logical bits of the target ciphertext obtained from the second signal pair to obtain a third intermediate ciphertext;

[0048] Decoding the third intermediate ciphertext using a second decoder to obtain a second intermediate ciphertext, wherein the second decoder corresponds to the second encoder;

[0049] decoding the second intermediate ciphertext using a first decoder to obtain a first intermediate ciphertext, where the first decoder corresponds to the first encoder;

[0050] The first intermediate ciphertext is decrypted using a second key to obtain plaintext information to be transmitted, where the second key is a key obtained from a shared key pool.

[0051] According to a quantum direct communication method provided by the present invention, the signal measurement result is obtained by the third-party device using single-photon interferometry measurement.

[0052] The present invention also provides a quantum direct communication device, comprising the following modules:

[0053] a signal sending module, configured to send a first photon sequence to a third-party device during target communication with a second communication terminal, wherein the first photon sequence includes a plurality of first optical pulse signals, each of the first optical pulse signals includes a plurality of coherent states having random light intensities and random phases, and the target communication is used to indicate measurement device-independent quantum direct communication;

[0054] a signal receiving module, configured to obtain a signal measurement result sent by the third-party device, the signal measurement result including a measurement result of the first photon sequence and a second photon sequence, the second photon sequence being sent by the second communication terminal to the third-party device, the second photon sequence including a plurality of second optical pulse signals, the plurality of second optical pulse signals corresponding to a sending time of the plurality of first optical pulse signals, each second optical pulse signal including a plurality of coherent states having random light intensities and random phases;

[0055] A parameter determination module is used to obtain channel parameters based on the signal measurement results, the first signal parameters corresponding to the first photon sequence, and the second signal parameter number corresponding to the second photon sequence, where the channel parameters are used to characterize the channel conditions of the target communication. The first signal parameters and the second signal parameters both include corresponding random light intensity parameters and random phase parameters. The second signal parameters are sent by the second communication terminal to the first communication terminal.

[0056] The present invention also provides an electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the quantum direct communication method described above is implemented.

[0057] 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 any of the above-described quantum direct communication methods.

[0058] The present invention also provides a computer program product, comprising a computer program, which, when executed by a processor, implements any of the above-described quantum direct communication methods.

[0059] The quantum direct communication method, device, electronic device and storage medium provided by the present invention can obtain channel parameters by using the coherent state of multi-intensity random phases contained in the photon sequence sent by the communicating party, thereby monitoring the channel status of the target communication, so as to further avoid photon number splitting attacks and reduce the attenuation of optical signals in the communication link. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] In order to more clearly illustrate the technical solutions in the present invention or the prior art, a brief introduction is given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0061] Figure 1 It is a flow chart of the quantum direct communication method provided by the present invention.

[0062] Figure 2 It is a schematic diagram of the process of sending an optical pulse signal by a communication terminal provided by the present invention.

[0063] Figure 3 It is a schematic diagram of the process of sending optical pulse signals in different coding modes provided by the present invention.

[0064] Figure 4 It is a schematic diagram of the communication terminal encoding and decoding process provided by the present invention.

[0065] Figure 5 It is a schematic diagram of the overall process of the information sending side provided by the present invention.

[0066] Figure 6 It is a schematic diagram of the overall flow of the information receiving side provided by the present invention.

[0067] Figure 7 It is a schematic structural diagram of the quantum direct communication device provided by the present invention.

[0068] Figure 8 It is a schematic diagram of the physical structure of the communication terminal provided by the present invention. DETAILED DESCRIPTION

[0069] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0070] Quantum secure communication boasts high security guaranteed by the principles of quantum mechanics and primarily encompasses technologies such as quantum key distribution (QKD), quantum direct communication (QSDC), and quantum secret sharing (QSS). Quantum direct communication directly transmits secret information over a quantum channel, eliminating the need for pre-distribution of keys between legitimate communicating parties. This simplifies communication architecture and management costs, and offers compatibility with existing optical communication networks. It represents a new paradigm for quantum secure communication. Because flaws in actual measurement equipment can lead to security vulnerabilities, device-independent quantum direct communication protocols have been proposed. By sending quantum states to an untrusted third party for measurement and publishing the results, legitimate communicating parties mitigate vulnerabilities in their own measurement equipment.

[0071] However, in measurement-device-independent quantum direct communication, the photon number splitting attack makes the multi-photon components in the optical pulse no longer safe and increases the channel attenuation of quantum direct communication.

[0072] In view of this, an embodiment of the present invention provides a quantum direct communication method. The method includes sending a first photon sequence to a third-party device during target communication with a second communication terminal. The first photon sequence includes multiple first optical pulse signals, each of which includes multiple coherent states with random light intensity and random phase. The method also includes obtaining a signal measurement result sent by the third-party device. Channel parameters are obtained based on the signal measurement results, a first signal parameter corresponding to the first photon sequence, and a second signal parameter corresponding to the second photon sequence. The channel parameters are used to characterize the channel conditions of the target communication. The first and second signal parameters each include a corresponding random light intensity parameter and a random phase parameter. The second signal parameter is sent from the second communication terminal to the first communication terminal. This method can obtain channel parameters, thereby monitoring the channel conditions of the target communication, further avoiding photon number splitting attacks in quantum direct communication, and reducing optical signal attenuation in the communication link.

[0073] The technical solutions in the embodiments of the present invention will be described below with reference to the accompanying drawings in the embodiments of the present invention.

[0074] Figure 1The figure is a flow chart of the quantum direct communication method provided by the present invention. The quantum direct communication method can be applied to a communication terminal, which can be various types of devices with information processing capabilities during implementation. For example, the communication terminal can include a personal computer, a laptop, a palmtop computer, or a server. Figure 1 As shown, the method may include the following steps 101 to 103:

[0075] Step 101: During target communication with a second communication terminal, a first photon sequence is sent to a third-party device, where the first photon sequence includes a plurality of first optical pulse signals, each of the first optical pulse signals includes a plurality of coherent states with random light intensity and random phase, and the target communication is used to indicate measurement device-independent quantum direct communication.

[0076] It should be noted that during the measurement device-independent quantum direct communication between the first communication terminal and the second communication terminal, the first communication terminal can send a first photon sequence to the third-party device. The first photon sequence includes multiple first optical pulse signals, and each of the first optical pulse signals includes multiple coherent states with random light intensity and random phase.

[0077] Step 102: Obtain a signal measurement result sent by the third-party device, where the signal measurement result includes a measurement result of the first photon sequence and a second photon sequence, where the second photon sequence is sent by the second communication terminal to the third-party device, and the second photon sequence includes a plurality of second optical pulse signals, where the plurality of second optical pulse signals correspond to transmission times of the plurality of first optical pulse signals, and each second optical pulse signal includes a plurality of coherent states having random light intensities and random phases.

[0078] It should be noted that the second communication terminal also sends a second photon sequence to the third-party device. The second photon sequence includes multiple second optical pulse signals. The signal measurement result includes the measurement results of the first photon sequence and the second photon sequence. The second photon sequence is sent by the second communication terminal to the third-party device. The second photon sequence includes multiple second optical pulse signals. The multiple second optical pulse signals correspond to the transmission time of the multiple first optical pulse signals. Each second optical pulse signal includes multiple coherent states with random light intensity and random phase. The first and second optical pulse signals can be used to obtain the channel status of the target communication.

[0079] Step 103: Obtain channel parameters based on the signal measurement results, the first signal parameters corresponding to the first photon sequence, and the second signal parameter number corresponding to the second photon sequence. The channel parameters are used to characterize the channel conditions of the target communication. The first signal parameters and the second signal parameters both include corresponding random light intensity parameters and random phase parameters. The second signal parameters are sent by the second communication terminal to the first communication terminal.

[0080] It should be noted that the channel parameters may include parameters such as information leakage. The channel parameters can be obtained based on the signal measurement results, the multiple first optical pulse signals, and the multiple second optical pulse signals. For example, the information leakage amount can be used to calculate the secure channel capacity.

[0081] It can be understood that the present invention adopts multi-intensity technology, that is, the photon sequence sent by the two communicating parties contains coherent states of multi-intensity random phases, which can be used to obtain channel parameters, that is, to obtain the channel conditions of the target communication, so that quantum direct communication can monitor and resist photon number splitting attacks, and reduce the attenuation of optical signals in the communication link.

[0082] Figure 2 FIG. 1 is a flow chart of the communication terminal sending an optical pulse signal provided by the present invention. Figure 2 As shown, the first photon sequence further includes a plurality of third optical pulse signals, and the plurality of third optical pulse signals are used for performing the target communication. During the process of performing the target communication with the second communication terminal, sending the first photon sequence to the third-party device may include:

[0083] Step 201: in the process of sending a first photon sequence to the third-party device, determining whether the coding mode corresponding to each optical pulse signal in the first photon sequence is the first mode or the second mode according to a preset selection probability.

[0084] Step 202: When it is determined that the encoding mode is the first mode, send the third optical pulse signal to the third-party device.

[0085] Step 203: When it is determined that the encoding mode is the second mode, the first optical pulse signal is sent to the third-party device.

[0086] It should be noted that the communication ends (information sender Alice and information receiver Bob) can select the coding mode (first mode) with a probability of 1-p and select the multi-intensity mode (second mode) with a probability of p, where p is much smaller than 1.

[0087] If the first mode is selected, both the information transmitter Alice and the information receiver Bob send pulse signals for target communication. If the second mode is selected, both the information transmitter Alice and the information receiver Bob send optical pulse signals containing coherent states of multiple intensity random phases to estimate the channel state of the target communication.

[0088] Furthermore, if the first communication terminal is the information transmitter of the target communication, in the process of sending the first photon sequence to the third-party device, before determining whether the coding mode corresponding to each optical pulse signal in the first photon sequence is the first mode or the second mode according to a preset selection probability, the method may also include: encoding and encrypting the plaintext to be transmitted to obtain the ciphertext to be transmitted; encoding and masking the portion of the ciphertext in the ciphertext to be transmitted to obtain the target ciphertext, wherein the portion of the ciphertext is a frame of ciphertext in the ciphertext to be transmitted. Sending the third optical pulse signal to the third-party device may include: obtaining a target number of coherent states with the same basis vector based on the logical bits of the target ciphertext, the target number of coherent states with the same basis vector being the third optical pulse signal; and sending the target number of coherent states with the same basis vector to the third-party device.

[0089] It should be noted that if the first communication terminal is the information transmitter, a target ciphertext must be generated before sending the optical pulse signal. First, the plaintext to be transmitted is encoded and encrypted to obtain the ciphertext to be transmitted. Then, a portion of the ciphertext to be transmitted is encoded and masked to obtain the target ciphertext. The portion of the ciphertext is a frame of ciphertext within the ciphertext to be transmitted. In other words, the third optical pulse signal is sent in a frame-by-frame manner.

[0090] If the first mode is selected, the first communication terminal as the information sender Alice sends M coherent states with the same basis vector ,in represents the coherent state light intensity, is a natural constant, b A =bM+A∈{0,1,…,2M-1}, b=0 or 1 is the logical bit of the target ciphertext formed by the information to be transmitted, A is the basis vector number, and M is the total number of basis vectors.

[0091] Furthermore, the first communication terminal is the information receiving end of the target communication, and sending the third optical pulse signal to the third-party device may include: obtaining random bits; obtaining a target number of coherent states with different basis vectors based on the random bits, and the target number of coherent states with different basis vectors is the third optical pulse signal; sending the target number of coherent states with different basis vectors to the third-party device.

[0092] It should be noted that if the first mode is selected, the first communication terminal acts as the information receiving terminal Bob, and sends M coherent states with different basis vectors ,in represents the coherent state light intensity, b B =b'M+B∈{0,1,…,2M-1} is a random bit, B represents the basis vector number, and the order of these coherent states is also random.

[0093] Furthermore, sending the first optical pulse signal to the third-party device may include: obtaining random light intensity and random phase, the random light intensity belonging to a preset light intensity range, and the random phase belonging to a preset phase range; obtaining a target number of coherent states with random light intensity and random phase based on the random light intensity and the random phase, and the target number of coherent states with random light intensity and random phase are the first optical pulse signal; and sending the target number of coherent states with random light intensity and random phase to the third-party device.

[0094] It should be noted that if the second mode is selected, the first communication terminal, as Alice or Bob, sends M coherent states with random light intensity and random phase. and , where the random light intensity β a and β b ∈{β0,β1,…}, random phase ϕ a and ϕ b ∈[0,2π), i represents the imaginary unit.

[0095] It can be understood that in the second mode, the photon sequence sent by the communicating parties contains coherent states of multiple intensity random phases, which can obtain channel parameters and thus monitor the channel conditions of the target communication to further avoid photon number splitting attacks and reduce the attenuation of optical signals in the communication link.

[0096] Figure 3 FIG. 1 is a flow chart of sending optical pulse signals in different coding modes provided by the present invention. Figure 3 As shown, BS: 50:50 beam splitter; D0, D1: single-photon detectors; VOA: variable optical attenuator; PM: phase modulator; IM: intensity modulator. From top to bottom, the first dashed box indicates the first encoding mode, and the second dashed box indicates the second multi-intensity mode. In the first mode, Alice's optical pulse contains M identical phase basis vectors, while Bob's contains M different phase basis vectors. In the second mode, Alice and Bob's optical pulses contain M coherent states of different intensities and phases.

[0097] In some embodiments, the attenuation of the target optical signal in the communication link greatly limits the maximum safe capacity and the longest communication distance of quantum direct communication.

[0098] In an embodiment of the present invention, the signal measurement result is obtained by the third-party device using single-photon interferometry measurement.

[0099] It can be understood that by using single-photon interferometry technology through third-party equipment, that is, the intermediate third party uses single-photon interferometry measurement instead of Bell Base measurement to measure the first optical pulse signal and the second optical pulse signal, it is equivalent to only one optical pulse signal being lost in the channel, thereby improving the maximum transmission distance of quantum direct communication.

[0100] In some embodiments, the second photon sequence may further include a fourth optical pulse signal sent based on target communication, wherein the plurality of fourth optical pulse signals correspond to the plurality of third optical pulse signals and are used for performing the target communication.

[0101] In an embodiment of the present invention, obtaining channel parameters based on the signal measurement results, a first signal parameter corresponding to the first photon sequence, and a second signal parameter corresponding to the second photon sequence may include: screening the plurality of first optical pulse signals, the plurality of second optical pulse signals, the plurality of third optical pulse signals, and the plurality of fourth optical pulse signals based on the signal measurement results to obtain a plurality of coarse-screened signal pairs, wherein the measurement result corresponding to each coarse-screened signal pair indicates that only one detector response of the third-party device is present. Determining a main channel capacity and a bonding channel capacity for the target communication based on the plurality of coarse-screened signal pairs, wherein the main channel capacity and the bonding channel capacity serve as the channel parameters.

[0102] It should be noted that a third-party device, Charlie, uses single-photon interferometry to measure the light pulses sent by Alice and Bob and publishes the measurement results. Charlie's measurement equipment includes a first single-photon detector D0 and a second single-photon detector D1. Upon detecting a single photon, these detectors generate identifiable electrical signals, called detector responses. Possible measurement results include: only the first detector responds, only the second detector responds, no detector responds, and both detectors respond. Alice and Bob discard events with no detector response and responses from both detectors, retaining only events with a single detector response. The light pulse pairs corresponding to these discarded events are also discarded and no longer used. The first and second light pulse signals form a pair (second mode), and the third and fourth light pulse signals form a pair (first mode). The multiple pre-screened signal pairs include both the first and second light pulse signals and the third and fourth light pulse signals.

[0103] After obtaining a plurality of coarse-screened signal pairs, further calculations may be performed based on the plurality of coarse-screened signals to determine the main channel capacity and the bonding channel capacity.

[0104] Furthermore, the second signal parameters also include coding modes corresponding to the multiple second optical pulse signals, and coding modes and basis vector information corresponding to the multiple fourth optical pulse signals. Determining the main channel capacity and the tie channel capacity of the target communication based on the multiple coarse-screened signal pairs may include: screening the multiple coarse-screened signal pairs according to the first signal parameters and the second signal parameters to obtain multiple fine-screened signal pairs, wherein the two optical pulse signals of the first signal pair in the multiple fine-screened signal pairs have the same coding mode, the same random optical intensity parameter, and a phase difference of the random phase parameter is 0 or π, and the two optical pulse signals of the second signal pair in the fine-screened signal pairs have the same coding mode and basis vector information. The first signal parameters include the coding mode, random optical intensity parameter, and random phase parameter corresponding to the multiple first optical pulse signals, and the coding mode and basis vector information corresponding to the multiple third optical pulse signals. The first signal pair is an optical pulse signal pair whose coding mode is the second mode, and the second signal pair is an optical pulse signal pair whose coding mode is the first mode. The wiring channel capacity of the target communication is determined based on multiple first signal pairs in the finely screened signal pairs; the logical bits of the target ciphertext are determined based on multiple second signal pairs in the finely screened signal pairs, and the main channel capacity of the target communication is determined.

[0105] It should be noted that after all measurements are completed, Alice and Bob announce the mode used when sending, and only retain the events that choose the same mode. For the first mode, Alice and Bob also announce the basis vector information A and B, and discard the events with different basis vectors. For the second mode, Alice and Bob also announce the light intensity β used. a , β b and phase ϕ a , ϕ b , only events with the same intensity and a phase difference of 0 or π are retained.

[0106] After the initial screening is complete, Alice and Bob randomly select some events from the retained first-mode events and publish the logical bits of the target ciphertext they loaded onto these coherent states. By comparing them, they can determine the quantum bit error rate and, from there, calculate the main channel capacity I(A:B). Alice and Bob use the retained second-mode events to estimate the amount of information leakage and calculate the bridge channel capacity I(A:E). The main channel capacity I(A:B) and the bridge channel capacity I(A:E) are then used to encode the next frame of optical pulses.

[0107] It can be understood that by using the first mode and the second mode encoding methods to encode the pulse signal when sending the optical pulse signal to obtain the channel parameters, and then using the channel parameters in the encoding process of the next frame of optical pulses, the channel state of quantum direct communication can be monitored to avoid photon number splitting attacks, and the encoding of the next frame of optical pulses can be adjusted according to the channel parameters, thereby improving the secure channel capacity and maximum communication distance of quantum direct communication.

[0108] In some embodiments, traditional phase encoding methods only utilize two phase dimensions and fail to maximize coding efficiency. The information transmitter Alice in this application encodes and encrypts the plaintext information to be transmitted to form the target ciphertext, mainly including forward error correction coding, security coding, and mask capacity increase (INCUM) processes, and adopts high-dimensional phase encoding technology to improve coding efficiency.

[0109] In an embodiment of the present invention, the channel parameters include the wiring channel capacity and the main channel capacity, and the encoding and encryption processing of the plaintext to be transmitted to obtain the ciphertext to be transmitted may include: encrypting the plaintext to be transmitted by a first key to obtain a first intermediate ciphertext, wherein the first key is a key obtained from a shared key pool; encoding the first intermediate ciphertext by a first encoder to obtain the ciphertext to be transmitted, and the ciphertext to be transmitted is stored in a first cache, and the first encoder is an error correction code encoder. The encoding and masking of part of the ciphertext to be transmitted to obtain the target ciphertext may include: retrieving a ciphertext sequence of a target length from the first cache to obtain the part of the ciphertext; encoding the part of the ciphertext by a second encoder to obtain a third intermediate ciphertext, wherein the security coding rate of the second encoder is a target value, and the length of the third intermediate ciphertext is a reference length; masking and increasing the third intermediate ciphertext with a first random sequence to obtain the target ciphertext, wherein the first random sequence is obtained by a random number generator; wherein the target value and the target length are determined based on the main channel capacity of the previous frame, the bonding channel capacity of the previous frame, and the safety communication limitation conditions obtained during the transmission of the previous frame of optical pulse signals, wherein the safety communication limitation conditions include the first value being less than or equal to the second value, and the target value being less than the main channel capacity of the previous frame, the first value being the quotient of the target length and the reference length, and the second value being the difference between the target value and the bonding channel capacity of the previous frame.

[0110] It should be noted that in the encoding process of the first mode, the information to be transmitted is divided into frames for transmission. Each frame contains both information bits and the key that can be extracted to encrypt the next frame. The ability of quantum direct communication to monitor eavesdroppers in the channel in real time makes this construction possible. mTo represent the plaintext that Alice wants to transmit to Bob, K∈{0,1} m The first key used to pre-encrypt T is taken from the shared key pool, and the first intermediate ciphertext generated is Y=T⊕K. Then use a code with a length of k and a code rate of r p And meet kr p = m error correction code encoder, such as low-density parity check (LDPC) encoder (first encoder), precodes Y to obtain the second intermediate ciphertext X∈{0,1} k , output to the first cache. Take out the length k from the first cache i (target length) sequence X i ∈{0,1} ki , which is the i-th frame information to be input into the security encoder (second encoder). If the first buffer is empty, V is generated from the random number generator (RNG) i For a secure coding rate of r i The second encoder input is X i Get the length n i The third intermediate ciphertext C i ∈{0,1} ni . The third intermediate ciphertext C i The random sequence L generated by RNG i ∈{0,1} ni Perform an exclusive OR (XOR) operation, which is the process of masked INCUM, to obtain the fourth intermediate ciphertext C i '=C i ⊕L i , which is the target ciphertext to be modulated into the quantum state. The main channel capacity of the i-th frame is expressed as C mi =I i (A:B), the bonding channel capacity is C wi =I i (A:E), then the secure channel capacity R i =C mi -C wi It can be obtained by calculation. Secure communication requires the above parameters to meet the following formula, which is the secure communication limitation condition:

[0111]

[0112] It is understood that the present invention employs high-dimensional phase encoding technology, i.e., encoding the target ciphertext on M phase basis vectors in a coherent state during encoding using the first mode. Selecting an appropriate M based on the experimental equipment and conditions can effectively reduce information leakage and increase the secure channel capacity and maximum transmission distance of quantum direct communication.

[0113] Furthermore, the method may also include: when the main channel capacity and the tie channel capacity meet the security communication limitation conditions, extracting the target shared key from the shared key pool for encoding the next frame of optical pulses; and sending the first random sequence to the second communication terminal.

[0114] It can be understood that compared with the solution without using multi-strength coding, i.e., the second mode, the safety channel capacity and the maximum communication distance are improved. Using the second mode can reduce the wired channel capacity, so the safety channel capacity R can be achieved. i =C mi -C wi Increase, the length that can be extracted is n i ×R i Available shared key S i When the first communication terminal is the information transmitter, the first random sequence is sent to the second communication terminal, and the second communication terminal can use the first random sequence for decoding to obtain plain text information.

[0115] In some embodiments, the information receiving terminal Bob can decode and decrypt the received ciphertext to obtain plaintext information corresponding to the target ciphertext. The first communication terminal is the information receiving terminal for the target communication, and the method may further include: obtaining a second random sequence sent by the second communication terminal; performing reverse masking and upscaling based on the second random sequence and the logical bits of the target ciphertext obtained from the second signal pair to obtain a third intermediate ciphertext; decoding the third intermediate ciphertext using a second decoder to obtain a second intermediate ciphertext, where the second decoder corresponds to the second encoder; decoding the second intermediate ciphertext using a first decoder to obtain a first intermediate ciphertext, where the first decoder corresponds to the first encoder; and decrypting the first intermediate ciphertext using a second key to obtain the plaintext information to be transmitted, where the second key is a key obtained from a shared key pool.

[0116] It should be noted that Alice announces the random bit L corresponding to the information received by Bob i , which is the second random sequence. Bob first reversely executes INCUM to obtain the third intermediate ciphertext C i = C i '⊕L i , where C i ' is obtained from the second signal pair screened out previously, and then decoded using a secure decoder (the decoder corresponding to the second encoder) to obtain the second intermediate ciphertext X, which is then decoded using an LDPC decoder or other error-correcting code decoder with similar functions (the decoder corresponding to the first encoder) to obtain the first intermediate ciphertext Y. Finally, the shared first key K obtained from the shared key pool is used to decrypt the original plaintext information T = Y ⊕ K.

[0117] Figure 4 This is a flow chart of the encoding and decoding process of the communication terminal provided by the present invention. Figure 4 As shown, BS: 50:50 beam splitter; D0, D1: single-photon detectors; RNG: random number generator. Dashed arrows indicate the direction of quantum bit transmission, and solid arrows indicate the direction of classical bit transmission. Dotted arrows are used only when the cache or key pool is exhausted or at the beginning of a new round of communication.

[0118] The following describes an exemplary application of an embodiment of the present invention in a practical application scenario.

[0119] In existing technologies, the attenuation of optical signals in communication links significantly limits the maximum secure capacity and maximum communication distance of quantum direct communication. Therefore, a quantum direct communication protocol is needed that can encode more information in high-dimensional quantum states and reduce channel loss, thereby increasing the secure channel capacity and maximum communication distance of quantum direct communication.

[0120] Figure 5 It is a schematic diagram of the overall process of the information sending side provided by the present invention. Figure 6 This is a schematic diagram of the overall process of the information receiving side provided by the present invention. Figure 5 and Figure 6 As shown, the method includes the following steps:

[0121] When a new round of communication begins, i.e., when i=1, X1 needs to be extracted from RNG. m0 , C w0 , k1 and r1 need to be appropriately selected according to formula (1), i.e., the secure communication constraint condition. m1 and C w1 When formula (1) is also satisfied, the available shared key S1 with a length of n1×R1 can be extracted.

[0122] When i>1 and the first buffer is sufficient, Alice's encoding process and Bob's decoding process are as follows:

[0123] 1. Alice uses the first key K∈{0,1} m Pre-encrypted plaintext message T∈{0,1} m The first intermediate ciphertext Y=T⊕K is formed.

[0124] 2. Alice uses the first encoder to precode Y and obtain the second intermediate ciphertext X∈{0,1} k and stored in the first cache.

[0125] 3. Alice takes the partial sequence X of the second intermediate ciphertext from the first cache i ∈{0,1} kiInput into the second encoder to complete the secure encoding, where each parameter must satisfy formula (1) to obtain the third intermediate ciphertext C i ∈{0,1} ni .

[0126] 4. Alice uses the random sequence L generated by RNG i ∈{0,1} ni Perform the INCUM operation to obtain the fourth intermediate ciphertext C i '=C i ⊕L i , which is also the target ciphertext to be modulated into the quantum state.

[0127] 5. Alice performs the steps of selecting the encoding mode described above. If the first mode is selected, the target ciphertext is modulated onto the quantum bit. If the second mode is selected, multi-intensity random phase quantum bits are prepared.

[0128] 6. Charlie performs the steps for measuring the optical pulse signal as described above.

[0129] 7. Repeat the above steps until the target ciphertext is completely transmitted.

[0130] 8. Alice and Bob perform the optical pulse screening steps of the communication protocol described above and calculate C mi , C wi and R i If formula (1) is satisfied, the shared key S can be extracted. i Used for encryption of subsequent information frames.

[0131] 9. Generate and use the random sequence L i Publish to public channels.

[0132] 10. Repeat the above steps until the first buffer is completely transferred.

[0133] 11. Alice publishes the random bit L corresponding to the information i , Bob receives random bits L i Bob first selects C from the second signal pair selected previously. i 'Reverse INCUM to obtain the third intermediate ciphertext C i = C i '⊕L i , then use the secure decoder (the second decoder, the decoder corresponding to the second encoder) to decode the second intermediate ciphertext X, and then use the LDPC decoder or other error correction code decoder with similar functions (the first decoder, the decoder corresponding to the first encoder) to decode the first intermediate ciphertext Y, and finally use the shared first key K to decrypt the original plaintext information T = Y ⊕ K.

[0134] The quantum direct communication method, apparatus, electronic device, and storage medium provided by the present invention relate to the field of quantum direct communication technology. The information transmission method comprises: a first communication terminal performs encoding using the encoding method to generate a first photon sequence comprising a first mode and a second mode, and transmits the first mode to an intermediate third-party device, wherein the first mode is a high-dimensional phase encoding of a target ciphertext in a coherent state, and the second mode is a coherent state of multiple intensity random phases; a second communication terminal generates a second photon sequence comprising two modes using the encoding method, and transmits the second photon sequence to the intermediate third-party device; the third-party device performs single-photon interferometry on the first and second photon sequences, generates and publishes the measurement results; the first and second communication terminals estimate the quantum bit error rate and information leakage based on the measurement results and pattern matching information in the first and second photon sequences; and the second communication terminal decodes the securely transmitted quantum bits using the decoding method to obtain the plaintext information corresponding to the target ciphertext. The quantum direct communication method, apparatus, electronic device, and storage medium provided by the present invention improve the secure channel capacity and maximum communication distance of quantum direct communication, meeting the requirements for secure and confidential inter-city communication.

[0135] Based on the foregoing embodiments, an embodiment of the present invention provides a quantum direct communication device, wherein each module included in the device and each unit included in each module can be implemented by a processor; of course, they can also be implemented by a specific logic circuit; in the implementation process, the processor can be a central processing unit (CPU), a microprocessor (MPU), a digital signal processor (DSP) or a field programmable gate array (FPGA), etc.

[0136] The quantum direct communication device provided by the present invention is described below. The quantum direct communication device described below and the quantum direct communication method described above can be referenced to each other.

[0137] Figure 7 This is a schematic diagram of the structure of the quantum direct communication device provided by the present invention. Figure 7 As shown, the apparatus 700 includes a signal sending module 701, a signal receiving module 702 and a parameter determination module 703, wherein:

[0138] A signal sending module 701 is configured to send a first photon sequence to a third-party device during target communication with a second communication terminal, where the first photon sequence includes a plurality of first optical pulse signals, each of the first optical pulse signals including a plurality of coherent states having random light intensities and random phases, and the target communication is used to indicate measurement device-independent quantum direct communication.

[0139] a signal receiving module 702, configured to obtain a signal measurement result sent by the third-party device, the signal measurement result including a measurement result of the first photon sequence and a second photon sequence, the second photon sequence being sent by the second communication terminal to the third-party device, the second photon sequence including a plurality of second optical pulse signals, the plurality of second optical pulse signals corresponding to transmission times of the plurality of first optical pulse signals, each second optical pulse signal including a plurality of coherent states having random optical intensities and random phases;

[0140] The parameter determination module 703 is used to obtain channel parameters based on the signal measurement results, the first signal parameters corresponding to the first photon sequence, and the second signal parameter number corresponding to the second photon sequence. The channel parameters are used to characterize the channel conditions of the target communication. The first signal parameters and the second signal parameters both include corresponding random light intensity parameters and random phase parameters. The second signal parameters are sent by the second communication terminal to the first communication terminal.

[0141] In some embodiments, the first photon sequence further includes a plurality of third optical pulse signals, which are used for the target communication. The signal sending module 701 includes a mode determination unit, a first sending unit, and a second sending unit. The mode determination unit is configured to determine, in a process of sending the first photon sequence to the third-party device, whether the coding mode corresponding to each optical pulse signal in the first photon sequence is the first mode or the second mode according to a preset selection probability; the first sending unit is configured to, if the coding mode is determined to be the first mode, send the third optical pulse signal to the third-party device; and the second sending unit is configured to, if the coding mode is determined to be the second mode, send the first optical pulse signal to the third-party device.

[0142] In some embodiments, the first communication terminal is the information transmitter of the target communication, and the apparatus further comprises an information encoding module configured to encode and encrypt plaintext to be transmitted to obtain ciphertext to be transmitted; encode and mask-update a portion of the ciphertext to be transmitted to obtain target ciphertext, wherein the portion of the ciphertext is a frame of ciphertext to be transmitted. The first transmitting unit is further configured to: obtain a target number of coherent states having the same basis vector based on the logical bits of the target ciphertext, wherein the target number of coherent states having the same basis vector is the third optical pulse signal; and transmit the target number of coherent states having the same basis vector to the third-party device.

[0143] In some embodiments, the first communication terminal is an information receiving end of the target communication, and the first sending unit is further used to: obtain random bits; obtain a target number of coherent states with different basis vectors based on the random bits, and the target number of coherent states with different basis vectors are the third optical pulse signal; and send the target number of coherent states with different basis vectors to the third-party device.

[0144] In some embodiments, the second sending unit is specifically used to: obtain random light intensity and random phase, the random light intensity belongs to a preset light intensity range, and the random phase belongs to a preset phase range; according to the random light intensity and the random phase, obtain a target number of coherent states with random light intensity and random phase, and the target number of coherent states with random light intensity and random phase are the first optical pulse signals; and send the target number of coherent states with random light intensity and random phase to the third-party device.

[0145] In some embodiments, the second photon sequence includes a plurality of fourth optical pulse signals, the plurality of fourth optical pulse signals corresponding to the plurality of third optical pulse signals, and used for the target communication. The parameter determination module 703 includes a signal coarse screening unit and a capacity acquisition unit. The signal coarse screening unit is configured to screen the plurality of first optical pulse signals, the plurality of second optical pulse signals, the plurality of third optical pulse signals, and the plurality of fourth optical pulse signals based on the signal measurement results to obtain a plurality of coarse-screened signal pairs, each of the coarse-screened signal pairs corresponding to a measurement result indicating that only one detector response of the third-party device exists. The capacity acquisition unit is configured to determine a main channel capacity and a bonding channel capacity of the target communication based on the plurality of coarse-screened signal pairs, the main channel capacity and the bonding channel capacity being the channel parameters.

[0146] In some embodiments, the second signal parameters further include coding modes corresponding to the multiple second optical pulse signals, and coding modes and basis vector information corresponding to the multiple fourth optical pulse signals. The capacity acquisition unit is specifically configured to: screen the multiple coarse-screened signal pairs according to the first signal parameters and the second signal parameters to obtain multiple fine-screened signal pairs, wherein the two optical pulse signals of a first signal pair in the multiple fine-screened signal pairs have the same coding mode, the same random optical intensity parameter, and a phase difference of a random phase parameter of 0 or π; the two optical pulse signals of a second signal pair in the fine-screened signal pairs have the same coding mode and basis vector information; the first signal parameters include the coding mode, random optical intensity parameter, and random phase parameter corresponding to the multiple first optical pulse signals, and the coding mode and basis vector information corresponding to the multiple third optical pulse signals; the first signal pair is an optical pulse signal pair with the second coding mode, and the second signal pair is an optical pulse signal pair with the first coding mode; determine the bonding channel capacity of the target communication according to the multiple first signal pairs in the fine-screened signal pairs; and determine the main channel capacity of the target communication according to the multiple second signal pairs in the fine-screened signal pairs.

[0147] In some embodiments, the channel parameters include the capacity of the wired channel and the capacity of the main channel, and the information encoding module is specifically used to: encrypt the plaintext to be transmitted by using a first key to obtain a first intermediate ciphertext, and the first key is a key obtained from a shared key pool; use a first encoder to encode the first intermediate ciphertext to obtain the ciphertext to be transmitted, and the ciphertext to be transmitted is stored in a first cache, and the first encoder is an error correction code encoder; take out a ciphertext sequence of a target length from the first cache to obtain the partial ciphertext; encode the partial ciphertext by using a second encoder to obtain a third intermediate ciphertext, and the security coding rate of the second encoder is a target value, and the third The length of the intermediate ciphertext is a reference length; the third intermediate ciphertext and the first random sequence are masked and increased to obtain the target ciphertext, and the first random sequence is obtained through a random number generator; wherein the target value and the target length are determined based on the main channel capacity of the previous frame, the wiring channel capacity of the previous frame, and the safety communication limitation conditions obtained during the transmission of the previous frame optical pulse signal, and the safety communication limitation conditions include that the first value is less than or equal to the second value, and the target value is less than the main channel capacity of the previous frame, the first value is the quotient of the target length and the reference length, and the second value is the difference between the target value and the wiring channel capacity of the previous frame.

[0148] In some embodiments, the information encoding module is also used to extract the target shared key from the shared key pool for encoding the next frame of optical pulses when the main channel capacity and the wired channel capacity meet the security communication limitation conditions; and send the first random sequence to the second communication terminal.

[0149] In some embodiments, the device also includes an information decoding module, which is used to: obtain a second random sequence sent by the second communication terminal; perform reverse masking and upscaling according to the second random sequence and the logical bits of the target ciphertext obtained from the second signal pair to obtain a third intermediate ciphertext; use a second decoder to decode the third intermediate ciphertext to obtain a second intermediate ciphertext, and the second decoder corresponds to the second encoder; decode the second intermediate ciphertext through a first decoder to obtain a first intermediate ciphertext, and the first decoder corresponds to the first encoder; use a second key to decrypt the first intermediate ciphertext to obtain plaintext information to be transmitted, and the second key is a key obtained from a shared key pool.

[0150] In some embodiments, the signal measurement result is obtained by the third-party device using single-photon interferometry.

[0151] In an embodiment of the present invention, the photon sequence sent by the communicating party contains coherent states of multiple intensity random phases, which can obtain channel parameters and thus monitor the channel conditions of the target communication to further avoid photon number splitting attacks and reduce the attenuation of optical signals in the communication link.

[0152] Figure 8 Schematic diagram of the physical structure of the communication terminal provided by the present invention. Figure 8As shown, the communication terminal 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 via the communication bus 840 . The processor 810 may call logic instructions in the memory 830 to execute a quantum direct communication method, the method comprising: during target communication with a second communication terminal, sending a first photon sequence to a third-party device, the first photon sequence comprising a plurality of first optical pulse signals, each of the first optical pulse signals comprising a plurality of coherent states having random light intensities and random phases, the target communication being used to indicate measurement device-independent quantum direct communication; obtaining a signal measurement result sent by the third-party device, the signal measurement result comprising a measurement result of the first photon sequence and a second photon sequence, the second photon sequence being sent by the second communication terminal to the third-party device, the second photon sequence comprising a plurality of second optical pulse signals, the plurality of second optical pulse signals corresponding to a transmission time of the plurality of first optical pulse signals, each of the second optical pulse signals comprising a plurality of coherent states having random light intensities and random phases; Channel parameters are obtained based on the signal measurement results, the first signal parameters corresponding to the first photon sequence, and the second signal parameter number corresponding to the second photon sequence. The channel parameters are used to characterize the channel conditions of the target communication. The first signal parameters and the second signal parameters both include corresponding random light intensity parameters and random phase parameters. The second signal parameters are sent by the second communication terminal to the first communication terminal.

[0153] Furthermore, the logic 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, or the portion that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product, stored in a storage medium, includes instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to perform all or part of the steps of the methods described in various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, mobile hard drives, read-only memories (ROMs), random access memories (RAMs), magnetic disks, or optical disks.

[0154] On the other hand, the present invention also provides a computer program product, which includes a computer program. The computer program can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer can execute the quantum direct communication method provided by the above methods, the method comprising: in the process of target communication with a second communication terminal, sending a first photon sequence to a third-party device, the first photon sequence including multiple first optical pulse signals, each of the first optical pulse signals including multiple coherent states with random light intensity and random phase, the target communication is used to indicate measurement device-independent quantum direct communication; obtaining a signal measurement result sent by the third-party device, the signal measurement result including a result obtained by measuring the first photon sequence and a second photon sequence, the second photon sequence is sent by the second communication terminal to the third-party device, the second photon sequence including multiple second optical pulse signals, the multiple second optical pulse signals corresponding to the sending time of the multiple first optical pulse signals, and each second optical pulse signal including multiple coherent states with random light intensity and random phase; Channel parameters are obtained based on the signal measurement results, the first signal parameters corresponding to the first photon sequence, and the second signal parameter number corresponding to the second photon sequence. The channel parameters are used to characterize the channel conditions of the target communication. The first signal parameters and the second signal parameters both include corresponding random light intensity parameters and random phase parameters. The second signal parameters are sent by the second communication terminal to the first communication terminal.

[0155] The computer program product includes one or more computer instructions. When loaded and executed on a computer, the computer program instructions fully or partially perform the processes or functions described in accordance with the embodiments of the present invention. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions may be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions may be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via a wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) method. The computer-readable storage medium may be any available medium capable of computer storage or a data storage device such as a server or data center that integrates one or more available media. The available medium may be magnetic media (e.g., floppy disks, hard disks, magnetic tapes), optical media (e.g., DVDs), or semiconductor media (e.g., solid-state drives (SSDs)).

[0156] On the other hand, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, is implemented to execute the quantum direct communication method provided by the above methods, the method comprising: in a process of target communication with a second communication terminal, sending a first photon sequence to a third-party device, the first photon sequence comprising a plurality of first optical pulse signals, each of the first optical pulse signals comprising a plurality of coherent states having random light intensity and random phase, the target communication being used to indicate measurement device-independent quantum direct communication; obtaining a signal measurement result sent by the third-party device, the signal measurement result comprising a result obtained by measuring the first photon sequence and a second photon sequence, the second photon sequence being sent by the second communication terminal to the third-party device, the second photon sequence comprising a plurality of second optical pulse signals, the plurality of second optical pulse signals corresponding to the sending time of the plurality of first optical pulse signals, each of the second optical pulse signals comprising a plurality of coherent states having random light intensity and random phase; Channel parameters are obtained based on the signal measurement results, the first signal parameters corresponding to the first photon sequence, and the second signal parameter number corresponding to the second photon sequence. The channel parameters are used to characterize the channel conditions of the target communication. The first signal parameters and the second signal parameters both include corresponding random light intensity parameters and random phase parameters. The second signal parameters are sent by the second communication terminal to the first communication terminal.

[0157] The computer-readable storage medium may be any combination of one or more computer-readable media. The computer-readable medium may be a computer-readable signal medium or a computer-readable storage medium. The computer-readable storage medium may be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples (a non-exhaustive list) of computer-readable storage media include: an electrical connection having one or more conductors, a portable computer disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM) or flash memory, optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination thereof. In this document, a computer-readable storage medium may be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, apparatus, or device.

[0158] A computer-readable signal medium may include a data signal propagated in baseband or as part of a carrier wave, which carries computer-readable program code. Such a propagated data signal may take a variety of forms, including, but not limited to, electromagnetic signals, optical signals, or any suitable combination thereof. A computer-readable signal medium may also be any computer-readable medium other than a computer-readable storage medium that can transmit, propagate, or transport a program for use by or in conjunction with an instruction execution system, apparatus, or device.

[0159] Program code embodied on a computer-readable medium may be transmitted using any appropriate medium, including but not limited to wireless, wireline, optical fiber cable, radio frequency (RF), etc., or any suitable combination of the foregoing.

[0160] Computer program code for performing the operations of this specification may be written in one or more programming languages, or a combination thereof, including object-oriented programming languages ​​such as Java, Smalltalk, and C++, as well as conventional procedural programming languages ​​such as "C" or similar programming languages. The program code may execute entirely on the user's computer, partially on the user's computer, as a stand-alone software package, partially on the user's computer and partially on a remote computer, or entirely on the remote computer or server. In the case of a remote computer, the remote computer may be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (e.g., through the Internet using an Internet service provider).

[0161] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, i.e., they may be located in one location or distributed across multiple network units. Some or all of the modules may be selected based on actual needs to achieve the objectives of the present embodiment. Persons of ordinary skill in the art will be able to understand and implement the present invention without inventive effort.

[0162] Through the above description of the embodiments, those skilled in the art will clearly understand that each embodiment can be implemented using software plus a necessary general-purpose hardware platform, or of course, hardware. Based on this understanding, the essence of the above technical solution, or the portion 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, a magnetic disk, or an optical disk, and includes a number of instructions for causing a computer device (such as a personal computer, server, or network device) to execute the methods described in each embodiment or certain portions of the embodiments.

[0163] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A quantum direct communication method, characterized in that: Applied to a first communication terminal, the method includes: During target communication with the second communication terminal, a first photon sequence is sent to a third-party device, where the first photon sequence includes a plurality of first optical pulse signals, each of the first optical pulse signals includes a plurality of coherent states having random light intensities and random phases, and the target communication is used to indicate measurement device-independent quantum direct communication; Obtaining a signal measurement result sent by the third-party device, the signal measurement result including a measurement result of the first photon sequence and a second photon sequence, where the second photon sequence is sent by the second communication terminal to the third-party device, the second photon sequence including a plurality of second optical pulse signals, the plurality of second optical pulse signals corresponding to transmission times of the plurality of first optical pulse signals, and each second optical pulse signal including a plurality of coherent states having random light intensities and random phases; Channel parameters are obtained based on the signal measurement results, the first signal parameters corresponding to the first photon sequence, and the second signal parameters corresponding to the second photon sequence. The channel parameters are used to characterize the channel conditions of the target communication. The first signal parameters and the second signal parameters both include corresponding random light intensity parameters and random phase parameters. The second signal parameters are sent by the second communication terminal to the first communication terminal.

2. The quantum direct communication method according to claim 1, characterized in that The first photon sequence further includes a plurality of third optical pulse signals, where the plurality of third optical pulse signals are used for performing the target communication. The sending of the first photon sequence to the third-party device during the target communication with the second communication terminal includes: In the process of sending the first photon sequence to the third-party device, determining, according to a preset selection probability, whether the coding mode corresponding to each optical pulse signal in the first photon sequence is the first mode or the second mode; When determining that the encoding mode is the first mode, sending the third optical pulse signal to the third-party device; When it is determined that the encoding mode is the second mode, the first optical pulse signal is sent to the third-party device.

3. The quantum direct communication method according to claim 2, characterized in that The first communication terminal is an information sending end of the target communication. In the process of sending the first photon sequence to the third-party device, before determining, according to a preset selection probability, whether the coding mode corresponding to each optical pulse signal in the first photon sequence is the first mode or the second mode, the method further includes: Encode and encrypt the plaintext to be transmitted to obtain the ciphertext to be transmitted; Performing encoding and masking capacity-increasing processing on a portion of the ciphertext to be transmitted to obtain a target ciphertext, wherein the portion of the ciphertext is a frame of ciphertext in the ciphertext to be transmitted; The sending the third optical pulse signal to the third-party device includes: Obtaining a target number of coherent states having the same basis vector according to the logical bits of the target ciphertext, wherein the target number of coherent states having the same basis vector is the third optical pulse signal; The target number of coherent states having the same basis vector is sent to the third-party device.

4. The quantum direct communication method according to claim 2, characterized in that The first communication terminal is an information receiving end of the target communication, and the sending of the third optical pulse signal to the third-party device includes: Get random bits; Obtaining a target number of coherent states with different basis vectors according to the random bits, wherein the target number of coherent states with different basis vectors is the third optical pulse signal; The target number of coherent states with different basis vectors is sent to the third-party device.

5. The quantum direct communication method according to claim 2, characterized in that The sending the first optical pulse signal to the third-party device includes: Acquire a random light intensity and a random phase, wherein the random light intensity falls within a preset light intensity range, and the random phase falls within a preset phase range; Obtaining a target number of coherent states with random light intensity and random phase according to the random light intensity and the random phase, wherein the target number of coherent states with random light intensity and random phase are the first optical pulse signals; The target number of coherent states with random light intensity and random phase are sent to the third-party device.

6. The quantum direct communication method according to claim 2, characterized in that: The second photon sequence includes a plurality of fourth optical pulse signals, the plurality of fourth optical pulse signals corresponding to the plurality of third optical pulse signals, and used for the target communication. The obtaining of the channel parameter according to the signal measurement result, a first signal parameter corresponding to the first photon sequence, and a second signal parameter number corresponding to the second photon sequence includes: screening the plurality of first optical pulse signals, the plurality of second optical pulse signals, the plurality of third optical pulse signals, and the plurality of fourth optical pulse signals according to the signal measurement result to obtain a plurality of roughly screened signal pairs, wherein a measurement result corresponding to each of the roughly screened signal pairs is that only one detector of the third-party device responds; The main channel capacity and the patching channel capacity of the target communication are determined according to the multiple coarse-screened signal pairs, and the main channel capacity and the patching channel capacity are the channel parameters.

7. The quantum direct communication method according to claim 6, characterized in that The second signal parameters further include coding modes corresponding to the plurality of second optical pulse signals, and coding modes and basis vector information corresponding to the plurality of fourth optical pulse signals. Determining the main channel capacity and the bonding channel capacity of the target communication based on the plurality of coarsely screened signal pairs includes: The multiple coarse-screened signal pairs are screened according to the first signal parameter and the second signal parameter to obtain multiple fine-screened signal pairs, wherein the two optical pulse signals of the first signal pair in the multiple fine-screened signal pairs have the same coding mode, the same random optical intensity parameter, and a phase difference of the random phase parameter is 0 or π, and the two optical pulse signals of the second signal pair in the fine-screened signal pairs have the same coding mode and basis vector information, the first signal parameter includes the coding mode, random optical intensity parameter, and random phase parameter corresponding to the multiple first optical pulse signals, and the coding mode and basis vector information corresponding to the multiple third optical pulse signals, the first signal pair is an optical pulse signal pair whose coding mode is the second mode, and the second signal pair is an optical pulse signal pair whose coding mode is the first mode; determining a bonding channel capacity for the target communication based on a plurality of first signal pairs among the finely screened signal pairs; The main channel capacity of the target communication is determined according to a plurality of second signal pairs in the finely screened signal pairs.

8. The quantum direct communication method according to claim 3, characterized in that: The channel parameters include the capacity of the tie channel and the capacity of the main channel. The encoding and encryption processing of the plaintext to be transmitted to obtain the ciphertext to be transmitted includes: Encrypting the plaintext to be transmitted using a first key to obtain a first intermediate ciphertext, where the first key is a key obtained from a shared key pool; Encoding the first intermediate ciphertext using a first encoder to obtain the ciphertext to be transmitted, wherein the ciphertext to be transmitted is stored in a first cache, and the first encoder is an error correction code encoder; The encoding and masking of part of the ciphertext to be transmitted to obtain target ciphertext includes: Retrieving a ciphertext sequence of a target length from the first buffer to obtain the partial ciphertext; Encoding the partial ciphertext using a second encoder to obtain a third intermediate ciphertext, wherein the security coding rate of the second encoder is a target value, and the length of the third intermediate ciphertext is a reference length; performing masked multiplication on the third intermediate ciphertext and a first random sequence to obtain the target ciphertext, where the first random sequence is obtained through a random number generator; The target value and the target length are determined based on the main channel capacity of the previous frame, the wiring channel capacity of the previous frame, and safety communication limitation conditions obtained during the transmission of the previous frame optical pulse signal. The safety communication limitation conditions include that the first value is less than or equal to the second value, and the target value is less than the main channel capacity of the previous frame. The first value is the quotient of the target length and the reference length, and the second value is the difference between the target value and the wiring channel capacity of the previous frame.

9. The quantum direct communication method according to claim 8, characterized in that The method further comprises: When the capacity of the main channel and the capacity of the bonding channel meet the secure communication restriction condition, extracting the target shared key from the shared key pool for encoding the next frame of optical pulses; The first random sequence is sent to the second communication terminal.

10. The quantum direct communication method according to claim 7, characterized in that: The first communication terminal is an information receiving terminal of the target communication, and the method further includes: Obtaining a second random sequence sent by the second communication terminal; Perform reverse masking and capacitation on the second random sequence and the logical bits of the target ciphertext obtained from the second signal pair to obtain a third intermediate ciphertext; Decoding the third intermediate ciphertext using a second decoder to obtain a second intermediate ciphertext, wherein the second decoder corresponds to the second encoder; decoding the second intermediate ciphertext using a first decoder to obtain a first intermediate ciphertext, where the first decoder corresponds to the first encoder; The first intermediate ciphertext is decrypted using a second key to obtain plaintext information to be transmitted, where the second key is a key obtained from a shared key pool.

11. The quantum direct communication method according to claim 1, characterized in that: The signal measurement result is obtained by the third-party device using single-photon interferometry measurement.

12. A quantum direct communication device, characterized in that: Applied to a first communication terminal, the apparatus includes: a signal sending module, configured to send a first photon sequence to a third-party device during target communication with a second communication terminal, wherein the first photon sequence includes a plurality of first optical pulse signals, each of the first optical pulse signals includes a plurality of coherent states having random light intensities and random phases, and the target communication is used to indicate measurement device-independent quantum direct communication; a signal receiving module, configured to obtain a signal measurement result sent by the third-party device, the signal measurement result including a measurement result of the first photon sequence and a second photon sequence, the second photon sequence being sent by the second communication terminal to the third-party device, the second photon sequence including a plurality of second optical pulse signals, the plurality of second optical pulse signals corresponding to a sending time of the plurality of first optical pulse signals, each second optical pulse signal including a plurality of coherent states having random light intensities and random phases; A parameter determination module is used to obtain channel parameters based on the signal measurement results, the first signal parameters corresponding to the first photon sequence, and the second signal parameter number corresponding to the second photon sequence, where the channel parameters are used to characterize the channel conditions of the target communication. The first signal parameters and the second signal parameters both include corresponding random light intensity parameters and random phase parameters. The second signal parameters are sent by the second communication terminal to the first communication terminal.

13. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the computer program, the quantum direct communication method according to any one of claims 1 to 11 is implemented.

14. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the quantum direct communication method according to any one of claims 1 to 11 is implemented.

15. A computer program product comprising a computer program, characterized in that When the computer program is executed by a processor, the quantum direct communication method according to any one of claims 1 to 11 is implemented.

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