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

Abstract

The invention provides a quantum direct communication method and device, electronic equipment and a storage medium, and relates to the technical field of quantum communication. The method comprises the steps that in the process of target communication with a second communication terminal, a first photon sequence is sent to third-party equipment, the first photon sequence comprises a plurality of first optical pulse signals, and each first optical pulse signal comprises a plurality of coherent states with random light intensity and random phase; acquiring a signal measurement result sent by the third-party device; and obtaining a channel parameter according to 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. In the embodiment of the invention, the photon sequence sent by the communication party contains the coherent state of the multi-intensity random phase, and the channel parameter can be obtained, so that the channel condition of the target communication is monitored, the photon number separation attack is further avoided, and the attenuation of the optical signal in the communication link is reduced.

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 has high security guaranteed by the principles of quantum mechanics, and mainly includes technical branches such as quantum key distribution (QKD), quantum direct communication (QSDC), and quantum secret sharing (QSS). Among them, quantum direct communication directly transmits secret information in the quantum channel, does not require the pre-distribution of keys between legitimate communication parties, simplifies the communication structure and management costs, and has the advantage of being compatible with existing optical communication networks. It is a new paradigm for quantum secure communication. Since defects in the actual measurement equipment may lead to security vulnerabilities, a measurement device-independent quantum direct communication protocol has been proposed. By sending the quantum state to an untrusted third party for measurement and publishing the measurement results, the legitimate communication party avoids the vulnerabilities of its 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 solve the defect in the prior art that photon number splitting attack leads to a reduction in the capacity of the secure channel. By using the coherent state of multi-intensity random phases contained in the photon sequence sent by the communicating party, channel parameters can be obtained, 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.

[0005] The present invention provides a quantum direct communication method, comprising the following steps: In the process of target communication with the second communication terminal, a first photon sequence is sent to a third-party device, 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 with random light intensity and random phase, and the target communication is used to indicate measurement device-independent quantum direct communication; Acquire 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 is sent by the second communication terminal to the third-party device, the second photon sequence comprises a plurality of second optical pulse signals, the plurality of second optical pulse signals correspond to the sending time of the plurality of first optical pulse signals, and each of the second optical pulse signals comprises a plurality of coherent states having random light intensities and random phases; A channel parameter is obtained according to 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. The channel parameter is used to characterize the channel condition of the target communication. The first signal parameter and the second signal parameter both include corresponding random light intensity parameters and random phase parameters. The second signal parameter is sent by the second communication terminal to the first communication terminal.

[0006] 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. In the process of performing the target communication with the second communication terminal, sending the first photon sequence to a third-party device includes: In the process of sending the first photon sequence to the third-party device, determining, according to a preset selection probability, that 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.

[0007] According to a quantum direct communication method provided by the present invention, the first communication terminal is the information sending end of the target communication, and in the process of sending the first photon sequence to the third-party device, before determining that 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 further includes: Encode and encrypt the plaintext to be transmitted to obtain the ciphertext to be transmitted; Performing encoding and masking capacity increase processing on part of the ciphertext to be transmitted to obtain target ciphertext, wherein the part 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: According to the logic bits of the target ciphertext, a target number of coherent states having the same basis vector are obtained, and the target number of coherent states having the same basis vector are the third optical pulse signal; The target number of coherent states having the same basis vector is sent to the third-party device.

[0008] 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: Get random bits; According to the random bits, a target number of coherent states with different basis vectors are obtained, and the target number of coherent states with different basis vectors are the third optical pulse signal; The target number of coherent states having different basis vectors are sent to the third-party device.

[0009] According to a quantum direct communication method provided by the present invention, 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 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, a target number of coherent states with random light intensity and random phase are obtained, and 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.

[0010] 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 correspond to the plurality of third optical pulse signals, and are used for the target communication, and the channel parameter is obtained according to the signal measurement result, the first signal parameter corresponding to the first photon sequence, and the second signal parameter number corresponding to the second photon sequence, including: 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 the 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 bonding channel capacity of the target communication are determined according to the plurality of roughly screened signal pairs, and the main channel capacity and the bonding channel capacity are the channel parameters.

[0011] According to a quantum direct communication method provided by the present invention, the second signal parameter further includes a coding mode corresponding to the plurality of second optical pulse signals, and a coding mode and basis vector information corresponding to the plurality of fourth optical pulse signals, and determining the main channel capacity and the wired channel capacity of the target communication according to 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 light intensity parameter, and the phase difference of the random phase parameter is 0 or π, 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 light 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 the bonding channel capacity of the target communication according to the plurality of first signal pairs in 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.

[0012] According to a quantum direct communication method provided by the present invention, the channel parameters include the capacity of the wired channel and the capacity of the main channel, and 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 by using a first key to obtain a first intermediate ciphertext, where the first key is a key obtained from a shared key pool; Using a first encoder to encode the first intermediate ciphertext to obtain the ciphertext to be transmitted, 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 includes: Taking out a ciphertext sequence of a target length from the first buffer to obtain the partial ciphertext; Encoding the partial 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; Performing masking and capacity increase on the third intermediate ciphertext and the first random sequence to obtain the target ciphertext, wherein the first random sequence is obtained through a random number generator; Among them, 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 limiting conditions obtained during the sending process of the previous frame optical pulse signal, and the safety communication limiting 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.

[0013] According to a quantum direct communication method provided by the present invention, the method further comprises: When the capacity of the main channel and the capacity of the tie-line 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.

[0014] 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: Acquire a second random sequence sent by the second communication terminal; Perform reverse masking and capacity increase according to the second random sequence and the logic 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 by a first decoder to obtain a first intermediate ciphertext, wherein 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.

[0015] 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.

[0016] The present invention also provides a quantum direct communication device, comprising the following modules: A signal sending module, used for sending 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 with random light intensity and random phase, 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 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 a sending time of the plurality of first optical pulse signals, and each of the second optical pulse signals comprising a plurality of coherent states having random light intensities and random phases; A parameter determination module is used to obtain channel parameters 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, wherein the channel parameters are used to characterize the channel conditions of the target communication, the first signal parameter and the second signal parameter both include corresponding random light intensity parameters and random phase parameters, and the second signal parameter is sent by the second communication terminal to the first communication terminal.

[0017] 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.

[0018] 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.

[0019] The present invention also provides a computer program product, comprising a computer program, wherein when the computer program is executed by a processor, the computer program implements any of the above-mentioned quantum direct communication methods.

[0020] 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

[0021] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces 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 creative work.

[0022] Figure 1 It is a flow chart of the quantum direct communication method provided by the present invention.

[0023] Figure 2 It is a schematic diagram of a flow chart of a communication terminal providing in the present invention sending an optical pulse signal.

[0024] Figure 3 It is a schematic diagram of the flow of sending optical pulse signals in different coding modes provided by the present invention.

[0025] Figure 4 It is a schematic diagram of the flow of encoding and decoding of the communication terminal provided by the present invention.

[0026] Figure 5 It is a schematic diagram of the overall process of the information sending side provided by the present invention.

[0027] Figure 6 It is a schematic diagram of the overall process of the information receiving side provided by the present invention.

[0028] Figure 7 It is a schematic diagram of the structure of the quantum direct communication device provided by the present invention.

[0029] Figure 8 It is a schematic diagram of the physical structure of the communication terminal provided by the present invention. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] Quantum secure communication has high security guaranteed by the principles of quantum mechanics, and mainly includes technical branches such as quantum key distribution (QKD), quantum direct communication (QSDC), and quantum secret sharing (QSS). Among them, quantum direct communication directly transmits secret information in the quantum channel, does not require the pre-distribution of keys between legitimate communication parties, simplifies the communication structure and management costs, and has the advantage of being compatible with existing optical communication networks. It is a new paradigm for quantum secure communication. Since defects in the actual measurement equipment may lead to security vulnerabilities, a measurement device-independent quantum direct communication protocol has been proposed. By sending the quantum state to an untrusted third party for measurement and publishing the measurement results, the legitimate communication party avoids the vulnerabilities of its own measurement equipment.

[0032] 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.

[0033] In view of this, an embodiment of the present invention provides a quantum direct communication method, which sends a first photon sequence to a third-party device during target communication with a second communication terminal, wherein the first photon sequence includes multiple first optical pulse signals, each of which includes multiple coherent states with random light intensity and random phase; obtains the signal measurement result sent by the third-party device; and obtains channel parameters according to the signal measurement result, the first signal parameter corresponding to the first photon sequence, and the second signal parameter number corresponding to the second photon sequence, wherein the channel parameters are used to characterize the channel status of the target communication, the first signal parameter and the second signal parameter both include corresponding random light intensity parameters and random phase parameters, and the second signal parameter is sent by the second communication terminal to the first communication terminal. The method can obtain channel parameters, thereby monitoring the channel status of the target communication, further avoiding the photon number splitting attack of quantum direct communication and reducing the attenuation of optical signals in the communication link.

[0034] The technical solutions in the embodiments of the present invention will be described below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0035] Figure 1 : 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: Step 101: During target communication with a second communication terminal, a first photon sequence is sent to a third-party device, 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 with random light intensity and random phase, and the target communication is used to indicate measurement device-independent quantum direct communication.

[0036] It should be noted that, during the process of 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 a third-party device, where 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.

[0037] Step 102: Obtain a signal measurement result sent by the third-party device, wherein the signal measurement result includes a result obtained by measuring the first photon sequence and a second photon sequence, wherein 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, wherein the plurality of second optical pulse signals correspond to a sending time of the plurality of first optical pulse signals, and each of the second optical pulse signals includes a plurality of coherent states having random light intensities and random phases.

[0038] It should be noted that the second communication terminal also sends a second photon sequence to the third-party device accordingly, the second photon sequence includes multiple second optical pulse signals, the signal measurement result includes the result of measuring 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 sending time of the multiple first optical pulse signals, and each of the second optical pulse signals includes multiple coherent states with random light intensity and random phase. The first optical pulse signal and the second optical pulse signal can be used to obtain the channel status of the target communication.

[0039] Step 103: Obtain channel parameters according to 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, wherein the channel parameters are used to characterize the channel conditions of the target communication, and the first signal parameter and the second signal parameter both include corresponding random light intensity parameters and random phase parameters, and the second signal parameter is sent by the second communication terminal to the first communication terminal.

[0040] It should be noted that the channel parameters may include parameters such as information leakage, and the signal measurement results, the plurality of first optical pulse signals and the plurality of second optical pulse signals may be used to obtain the channel parameters, for example, to obtain the information leakage, and the signal leakage may be used to calculate the secure channel capacity, etc.

[0041] 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.

[0042] Figure 2 FIG. 1 is a flow chart of the communication terminal sending an optical pulse signal provided by the present invention. Figure 2As shown, the first photon sequence also includes a plurality of third optical pulse signals, and the plurality of third optical pulse signals are used for performing the target communication. In the process of performing the target communication with the second communication terminal, sending the first photon sequence to the third-party device may include: Step 201: in the process of sending a first photon sequence to the third-party device, determining whether a coding mode corresponding to each optical pulse signal in the first photon sequence is a first mode or a second mode according to a preset selection probability.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] If the first mode is selected, the information sending end Alice and the information receiving end Bob both send pulse signals for target communication. If the second mode is selected, the information sending end Alice and the information receiving end Bob both send optical pulse signals containing coherent states of multi-intensity random phases for estimating the channel state of the target communication.

[0047] Furthermore, if the first communication terminal is the information sending end 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 the 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 part of the ciphertext in the ciphertext to be transmitted to obtain the target ciphertext, wherein the part 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 according to the logical bits of the target ciphertext, wherein the target number of coherent states with the same basis vector is the third optical pulse signal; and sending the target number of coherent states with the same basis vector to the third-party device.

[0048] It should be noted that if the first communication terminal is an information sending end, a target ciphertext needs to 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, part of the ciphertext in the ciphertext to be transmitted is encoded and masked to obtain the target ciphertext, where the part of the ciphertext is a frame of ciphertext in the ciphertext to be transmitted, that is, the third optical pulse signal is sent in a frame-by-frame manner.

[0049] 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.

[0050] Furthermore, the first communication terminal is an information receiving end of the target communication, and sending the third optical pulse signal to the third-party device may include: acquiring 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 are the third optical pulse signal; and sending the target number of coherent states with different basis vectors to the third-party device.

[0051] 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.

[0052] 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 according to the random light intensity and the random phase, the target number of coherent states with random light intensity and random phase being 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.

[0053] 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.

[0054] 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.

[0055] 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 dotted box indicates that the encoding mode is the first mode, and the second dotted box indicates the multi-intensity mode, which is the second mode. In the first mode, Alice's optical pulse contains M identical phase basis vectors, and Bob contains M different phase basis vectors. In the second mode, Alice and Bob's optical pulses contain M coherent states of different light intensities and phases.

[0056] 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.

[0057] In an embodiment of the present invention, the signal measurement result is obtained by the third-party device using single-photon interferometry measurement.

[0058] 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.

[0059] 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.

[0060] In an embodiment of the present invention, obtaining the channel parameters according to the signal measurement result, the first signal parameter corresponding to the first photon sequence, and the second signal parameter number corresponding to the second photon sequence may include: screening the multiple first optical pulse signals, the multiple second optical pulse signals, the multiple third optical pulse signals, and the multiple fourth optical pulse signals according to the signal measurement result to obtain multiple coarse-screened signal pairs, and the measurement result corresponding to each coarse-screened signal pair is that the third-party device has only one detector response. According to the multiple coarse-screened signal pairs, the main channel capacity and the bonding channel capacity of the target communication are determined, and the main channel capacity and the bonding channel capacity are the channel parameters.

[0061] It should be noted that the third-party device Charlie uses single-photon interferometry to measure the optical 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, which generate identifiable electrical signals after detecting single photons, 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 events with both detectors responding, that is, only events with only one detector responding are retained. The optical pulse pairs corresponding to the discarded events are also discarded and no longer used. The first optical pulse signal and the second optical pulse signal are a pair (second mode), and the third optical pulse signal and the fourth optical pulse signal are a pair (first mode). Multiple coarsely screened signal pairs include both signal pairs consisting of the first optical pulse signal and the second optical pulse signal, and signal pairs consisting of the third optical pulse signal and the fourth optical pulse signal.

[0062] After obtaining a plurality of roughly screened signal pairs, further calculations may be performed based on the plurality of roughly screened signals to determine the main channel capacity and the bonding channel capacity.

[0063] 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 according to 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 coding modes of the two optical pulse signals of the first signal pair in the multiple fine-screened signal pairs are the same, the random light intensity parameters are the same, and the phase difference of the random phase parameters is 0 or π, and the coding modes and basis vector information of the two optical pulse signals of the second signal pair in the fine-screened signal pairs are the same, the first signal parameters include the coding modes, random light intensity parameters and random phase parameters corresponding to the multiple first optical pulse signals, and the coding modes 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. According to the multiple first signal pairs in the finely screened signal pairs, the wiring channel capacity of the target communication is determined; according to the multiple second signal pairs in the finely screened signal pairs, the logical bits of the target ciphertext are determined, and the main channel capacity of the target communication is determined.

[0064] It should be noted that when all measurements are completed, Alice and Bob announce the mode used when sending, and only keep the events that choose the same mode. For the first mode, Alice and Bob also publish the basis vector information A and B, and discard the events with different basis vectors. For the second mode, Alice and Bob also publish the light intensity β used a , β b and phase φ a , ϕ b , only events with the same light intensity and a phase difference of 0 or π are retained.

[0065] Among them, after the previous screening is completed, Alice and Bob randomly select some events from the retained first mode events and publish the logical bits of the target ciphertext they loaded on these coherent states. By comparison, the quantum bit error rate can be obtained, and then the main channel capacity I (A:B) can be calculated. Alice and Bob use the retained second mode events to estimate the amount of information leakage and calculate the wired channel capacity I (A:E). The main channel capacity I (A:B) and the wired channel capacity I (A:E) will be used in the encoding process of the next frame of optical pulses.

[0066] It can be understood that by using the first mode and the second mode to encode the pulse signal to obtain the channel parameters when sending the optical pulse signal, 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 next frame of optical pulse encoding can be adjusted according to the channel parameters, thereby improving the secure channel capacity and maximum communication distance of quantum direct communication.

[0067] In some embodiments, the traditional phase encoding method only uses two dimensions of the phase and does not maximize the coding efficiency. The information transmitter Alice of the present application encodes and encrypts the plaintext information to be transmitted to form the target ciphertext, which mainly includes forward error correction coding, security coding and mask capacity increase (INCUM) and other processes, and adopts high-dimensional phase encoding technology to improve the coding efficiency.

[0068] In an embodiment of the present invention, the channel parameters include the capacity of the wiring channel and the capacity of the main channel, 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, and 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: taking out 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; performing masking and masking of the third intermediate ciphertext and 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 according to the main channel capacity of the previous frame, the wiring channel capacity of the previous frame, and the safety communication limiting conditions obtained during the transmission of the previous frame of optical pulse signals, wherein the safety communication limiting 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.

[0069] 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 characteristic 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 taken from the shared key pool is used to pre-encrypt T. The first intermediate ciphertext generated is Y=T⊕K. Then use 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 a string of 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 capacity increase INCUM, and 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 capacity of the wiring channel is C wi =I i (A:E), then the achievable 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: It is understandable that the present invention adopts high-dimensional phase encoding technology, that is, in the process of encoding using the first mode, the target ciphertext is encoded on M phase basis vectors in the coherent state. Selecting a suitable M according to the experimental equipment and experimental conditions can effectively reduce the amount of information leakage and improve the secure channel capacity and maximum transmission distance of quantum direct communication.

[0070] Furthermore, the method may also include: when the main channel capacity and the tie-up channel capacity meet the secure communication restriction 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.

[0071] It can be understood that compared with the solution without using multi-intensity coding, i.e., the second mode, the safety channel capacity and the maximum communication distance are improved. Using the second mode can reduce the bonding 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 sending end, 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.

[0072] In some embodiments, the information receiving end Bob can decode and decrypt the received ciphertext to obtain the plaintext information corresponding to the target ciphertext. The first communication terminal is the information receiving end of the target communication, and the method may also include: obtaining a second random sequence sent by the second communication terminal; performing reverse masking and capacity expansion 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; decoding the third intermediate ciphertext using a second decoder to obtain a second intermediate ciphertext, the second decoder corresponding to the second encoder; decoding the second intermediate ciphertext using a first decoder to obtain a first intermediate ciphertext, the first decoder corresponding to the first encoder; decrypting the first intermediate ciphertext using a second key to obtain the plaintext information to be transmitted, the second key being a key obtained from a shared key pool.

[0073] It should be noted that Alice publishes 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 (decoder corresponding to the second encoder) to obtain the second intermediate ciphertext X, which is then decoded by an LDPC decoder or other error correction code decoder with similar functions (decoder corresponding to the first encoder) to obtain the first intermediate ciphertext Y, and finally decrypted using the shared first key K obtained from the shared key pool to obtain the original plaintext information T=Y⊕K.

[0074] Figure 4 Schematic diagram 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. The dashed arrows indicate the transmission direction of quantum bits, and the solid arrows indicate the transmission direction of classical bits. The dotted arrows are only used when the cache or key pool is exhausted and a new round of communication begins.

[0075] The following describes an exemplary application of an embodiment of the present invention in a practical application scenario.

[0076] In the prior art, the attenuation of optical signals in communication links greatly limits the maximum safe capacity and the longest communication distance of quantum direct communication. Based on this, a quantum direct communication protocol is needed that can encode more information on high-dimensional quantum states and reduce channel loss, so as to improve the safe channel capacity and the maximum communication distance of quantum direct communication.

[0077] 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 comprises the following steps: When a new round of communication begins, that is, 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. m1 and C w1 When formula (1) is also satisfied, a usable shared key S1 with a length of n1×R1 can be extracted.

[0078] When i>1 and the first buffer is sufficient, Alice's encoding process and Bob's decoding process are as follows: 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.

[0079] 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.

[0080] 3. Alice takes out 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 .

[0081] 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.

[0082] 5. Alice executes 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.

[0083] 6. Charlie performs the steps for measuring the optical pulse signal as described above.

[0084] 7. Repeat the above steps until the target ciphertext is completely transmitted.

[0085] 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.

[0086] 9. Generate and use the random sequence L i Publish to public channels.

[0087] 10. Repeat the above steps until the first buffer is completely transmitted.

[0088] 11. Alice publishes the information corresponding to the random bit L i , Bob receives a random bit L i Bob first selects C from the second signal pair selected previously. i 'Execute INCUM in reverse order to obtain the third intermediate ciphertext C i = C i '⊕L i , and then use the security 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 and obtain the original plaintext information T=Y⊕K.

[0089] The quantum direct communication method, device, 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 by the encoding method, generates a first photon sequence including a first mode and a second mode and sends it to an intermediate third-party device, wherein the first mode is a high-dimensional phase encoding for a target ciphertext on a coherent state, and the second mode is a coherent state of a multi-intensity random phase; a second communication terminal generates a second photon sequence with two modes by the encoding method and sends it to an intermediate third-party device; the third-party device performs single-photon interference measurement on the first photon sequence and the second photon sequence, generates and publishes the measurement results; the first and second communication terminals perform quantum bit error rate estimation and information leakage estimation according to the measurement results and the pattern matching information in the first and second photon sequences; the second communication terminal decodes the securely transmitted quantum bits by the decoding method to obtain the plaintext information corresponding to the target ciphertext. The quantum direct communication method, device, electronic device and storage medium provided by the present invention improve the secure channel capacity and maximum communication distance of quantum direct communication, and meet the requirements of secure and confidential communication between metropolitan areas.

[0090] Based on the foregoing embodiments, an embodiment of the present invention provides a quantum direct communication device, and each module included in the device and each unit included in each module can be implemented by a processor; of course, it 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.

[0091] 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.

[0092] Figure 7 Schematic diagram of the structure of the quantum direct communication device provided by the present invention. Figure 7 As shown, the device 700 includes a signal sending module 701, a signal receiving module 702 and a parameter determination module 703, wherein: A signal sending module 701 is used 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 which 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; A signal receiving module 702 is used to obtain a signal measurement result sent by the third-party device, wherein the signal measurement result includes a result obtained by measuring the first photon sequence and a second photon sequence, wherein 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, wherein the plurality of second optical pulse signals correspond to a sending time of the plurality of first optical pulse signals, and each of the second optical pulse signals includes a plurality of coherent states having random light intensities and random phases; The parameter determination module 703 is used to obtain channel parameters according to 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, wherein the channel parameters are used to characterize the channel conditions of the target communication, and the first signal parameters and the second signal parameters both include corresponding random light intensity parameters and random phase parameters, and the second signal parameters are sent by the second communication terminal to the first communication terminal.

[0093] In some embodiments, 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. The signal sending module 701 includes a mode determination unit, a first sending unit, and a second sending unit. The mode determination unit is used to determine 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 during the process of sending the first photon sequence to the third-party device; the first sending unit is used to send the third optical pulse signal to the third-party device when determining that the coding mode is the first mode; and the second sending unit is used to send the first optical pulse signal to the third-party device when determining that the coding mode is the second mode.

[0094] In some embodiments, the first communication terminal is the information sending end of the target communication, and the device further includes an information encoding module, the information encoding module is used to encode and encrypt the plaintext to be transmitted to obtain the ciphertext to be transmitted; encode and mask the part of the ciphertext to be transmitted to obtain the target ciphertext, and the part of the ciphertext is a frame of ciphertext in the ciphertext to be transmitted. The first sending unit is also used to: obtain a target number of coherent states with the same basis vector according to the logical bits of the target ciphertext, and the target number of coherent states with the same basis vector is the third optical pulse signal; send the target number of coherent states with the same basis vector to the third-party device.

[0095] 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.

[0096] 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 signal; send the target number of coherent states with random light intensity and random phase to the third-party device.

[0097] In some embodiments, the second photon sequence includes a plurality of fourth optical pulse signals, the plurality of fourth optical pulse signals correspond to the plurality of third optical pulse signals, and are 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 used 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 according to the signal measurement result to obtain a plurality of coarse-screened signal pairs, and the measurement result corresponding to each of the coarse-screened signal pairs is that the third-party device has only one detector response; the capacity acquisition unit is used to determine the main channel capacity and the bonding channel capacity of the target communication according to the plurality of coarse-screened signal pairs, and the main channel capacity and the bonding channel capacity are the channel parameters.

[0098] In some embodiments, 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, and the capacity acquisition unit is specifically used 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 coding modes of the two optical pulse signals of the first signal pair in the multiple fine-screened signal pairs are the same, the random light intensity parameters are the same, and the phase difference of the random phase parameters is 0 or π, and the coding modes and basis vector information of the two optical pulse signals of the second signal pair in the fine-screened signal pairs are the same, the first signal parameters include the coding modes, random light intensity parameters and random phase parameters corresponding to the multiple first optical pulse signals, and the coding modes 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 wiring channel capacity of the target communication according to the multiple first signal pairs in the fine-screened signal pairs; determine the main channel capacity of the target communication according to the multiple second signal pairs in the fine-screened signal pairs.

[0099] 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; encode the first intermediate ciphertext by using 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; 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 limiting conditions obtained during the sending process of the previous frame optical pulse signal, and the safety communication limiting 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.

[0100] 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 tie channel capacity meet the security communication restriction conditions; and send the first random sequence to the second communication terminal.

[0101] 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 capacity expansion 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 by 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.

[0102] In some embodiments, the signal measurement result is obtained by the third-party device using single photon interferometry.

[0103] 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, so as to further avoid photon number splitting attacks and reduce the attenuation of optical signals in the communication link.

[0104] 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 (processor) 810, a communication interface (Communications Interface) 820, a memory (memory) 830 and a communication bus 840, wherein the processor 810, the communication interface 820, and the memory 830 communicate with each other through the communication bus 840. The processor 810 may call the logic instructions in the memory 830 to execute the quantum direct communication method, which includes: in the process of performing target communication with the second communication terminal, sending a first photon sequence to a third-party device, the first photon sequence including a plurality of first optical pulse signals, each of the first optical pulse signals including 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; 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 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, and each of the second optical pulse signals including a plurality of coherent states with random light intensity and random phase; A channel parameter is obtained according to 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. The channel parameter is used to characterize the channel condition of the target communication. The first signal parameter and the second signal parameter both include corresponding random light intensity parameters and random phase parameters. The second signal parameter is sent by the second communication terminal to the first communication terminal.

[0105] In addition, the logic instructions in the above-mentioned memory 830 can be implemented in the form of a software functional unit and can be stored in a computer-readable storage medium when it is sold or used as an independent product. Based on this understanding, the technical solution of the present invention is essentially or the part that contributes to the prior art or the part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions to enable a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program codes.

[0106] On the other hand, the present invention further provides a computer program product, the computer program product 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 the 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 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, 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 includes 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 includes a plurality of second optical pulse signals, the plurality of second optical pulse signals correspond to the sending time of the plurality of first optical pulse signals, each of the second optical pulse signals includes a plurality of coherent states with random light intensity and random phase; A channel parameter is obtained according to 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. The channel parameter is used to characterize the channel condition of the target communication. The first signal parameter and the second signal parameter both include corresponding random light intensity parameters and random phase parameters. The second signal parameter is sent by the second communication terminal to the first communication terminal.

[0107] The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the process or function described in the embodiment of the present invention is generated in whole or in part. 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 computer-readable storage medium. For example, the computer instructions may be transmitted from one website, computer, server, or data center to another website, computer, server, or data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium may be any available medium that a computer can store or a data storage device such as a server or data center that includes one or more available media integrated therein. The available medium may be a magnetic medium (e.g., a floppy disk, a hard disk, a tape), an optical medium (e.g., a DVD), or a semiconductor medium (e.g., a solid-state drive Solid State Disk (SSD)), etc.

[0108] On the other hand, the present invention further provides a non-transitory computer-readable storage medium having a computer program stored thereon, which is implemented when the computer program is executed by a processor to 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 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; A channel parameter is obtained according to 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. The channel parameter is used to characterize the channel condition of the target communication. The first signal parameter and the second signal parameter both include corresponding random light intensity parameters and random phase parameters. The second signal parameter is sent by the second communication terminal to the first communication terminal.

[0109] The above-mentioned computer-readable storage medium can adopt any combination of one or more computer-readable media. The computer-readable medium can be a computer-readable signal medium or a computer-readable storage medium. The computer-readable storage medium can be, for example, - but not limited to - an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device or device, or any combination of the above. More specific examples (non-exhaustive list) of computer-readable storage media include: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM) or flash memory, an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In this document, a computer-readable storage medium can be any tangible medium containing or storing a program, which can be used by an instruction execution system, device or device or used in combination with it.

[0110] Computer-readable signal media may include a data signal propagated in baseband or as part of a carrier wave, which carries a computer-readable program code. Such propagated data signals may take a variety of forms, including, but not limited to, electromagnetic signals, optical signals, or any suitable combination of the above. Computer-readable signal media may also be any computer-readable medium other than a computer-readable storage medium, which may send, propagate, or transmit a program for use by or in conjunction with an instruction execution system, apparatus, or device.

[0111] The program code embodied on the computer-readable medium may be transmitted using any appropriate medium, including but not limited to wireless, wire, optical cable, radio frequency (RF), etc., or any suitable combination of the foregoing.

[0112] Computer program code for performing the operations of the present specification may be written in one or more programming languages ​​or a combination thereof, including object-oriented programming languages ​​such as Java, Smalltalk, C++, and conventional procedural programming languages ​​such as "C" or similar programming languages. The program code may be executed entirely on the user's computer, partially on the user's computer, as a separate software package, partially on the user's computer and partially on a remote computer, or entirely on a 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).

[0113] The device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Ordinary technicians in this field can understand and implement it without paying creative labor.

[0114] Through the description of the above implementation methods, those skilled in the art can clearly understand that each implementation method can be implemented by means of software plus a necessary general hardware platform, and of course, can also be implemented by hardware. Based on this understanding, the above technical solution is essentially or the part that contributes to the prior art can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a disk, an optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0115] 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 embodiments of the present invention.

Claims

1. A quantum direct communication method, characterized in that: Applied to a first communication terminal, the method includes: In the process of target communication with the second communication terminal, a first photon sequence is sent to a third-party device, 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 with random light intensity and random phase, and the target communication is used to indicate measurement device-independent quantum direct communication; Acquire 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 is sent by the second communication terminal to the third-party device, the second photon sequence comprises a plurality of second optical pulse signals, the plurality of second optical pulse signals correspond to the sending time of the plurality of first optical pulse signals, and each of the second optical pulse signals comprises a plurality of coherent states having random light intensities and random phases; A channel parameter is obtained according to 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. The channel parameter is used to characterize the channel condition of the target communication. The first signal parameter and the second signal parameter both include corresponding random light intensity parameters and random phase parameters. The second signal parameter is 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, and the plurality of third optical pulse signals are used for performing the target communication. In the process of performing the target communication with the second communication terminal, sending the first photon sequence to the third-party device includes: In the process of sending the first photon sequence to the third-party device, determining, according to a preset selection probability, that 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 that 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 further includes: Encode and encrypt the plaintext to be transmitted to obtain the ciphertext to be transmitted; Performing encoding and masking capacity increase processing on part of the ciphertext to be transmitted to obtain target ciphertext, wherein the part 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: According to the logic bits of the target ciphertext, a target number of coherent states having the same basis vector are obtained, and the target number of coherent states having the same basis vector are 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; According to the random bits, a target number of coherent states with different basis vectors are obtained, and the target number of coherent states with different basis vectors are the third optical pulse signal; The target number of coherent states having different basis vectors are 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 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, a target number of coherent states with random light intensity and random phase are obtained, and 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 correspond to the plurality of third optical pulse signals, and are used for the target communication, and obtaining the channel parameter according to the signal measurement result, the first signal parameter corresponding to the first photon sequence, and the second signal parameter number corresponding to the second photon sequence, comprises: 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 the 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 bonding channel capacity of the target communication are determined according to the plurality of roughly screened signal pairs, and the main channel capacity and the bonding channel capacity are the channel parameters.

7. The quantum direct communication method according to claim 6, characterized in that: The second signal parameters also 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. The determining of the main channel capacity and the bonding channel capacity of the target communication according to 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 light intensity parameter, and the phase difference of the random phase parameter is 0 or π, 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 light 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 the bonding channel capacity of the target communication according to the plurality of first signal pairs in 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 wiring channel and the capacity of the main channel. The encoding and encryption of the plaintext to be transmitted to obtain the ciphertext to be transmitted includes: Encrypting the plaintext to be transmitted by using a first key to obtain a first intermediate ciphertext, where the first key is a key obtained from a shared key pool; Using a first encoder to encode the first intermediate ciphertext to obtain the ciphertext to be transmitted, 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 includes: Taking out a ciphertext sequence of a target length from the first buffer to obtain the partial ciphertext; Encoding the partial 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; Performing masking and capacity increase on the third intermediate ciphertext and the first random sequence to obtain the target ciphertext, wherein the first random sequence is obtained through a random number generator; Among them, 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 limiting conditions obtained during the sending process of the previous frame optical pulse signal, and the safety communication limiting 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 tie-line 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: Acquire a second random sequence sent by the second communication terminal; Perform reverse masking and capacity increase according to the second random sequence and the logic 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 by a first decoder to obtain a first intermediate ciphertext, wherein 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.

12. A quantum direct communication device, characterized in that: Applied to a first communication terminal, the device includes: A signal sending module, used for sending 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 with random light intensity and random phase, 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 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 a sending time of the plurality of first optical pulse signals, and each of the second optical pulse signals comprising a plurality of coherent states having random light intensities and random phases; A parameter determination module is used to obtain channel parameters 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, wherein the channel parameters are used to characterize the channel conditions of the target communication, the first signal parameter and the second signal parameter both include corresponding random light intensity parameters and random phase parameters, and the second signal parameter is 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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