CN112953647A

CN112953647A - Quantum communication method, quantum communication device, computer equipment and storage medium

Info

Publication number: CN112953647A
Application number: CN202110223948.3A
Authority: CN
Inventors: 不公告发明人
Original assignee: Tsinghua University
Current assignee: Tsinghua University
Priority date: 2021-03-01
Filing date: 2021-03-01
Publication date: 2021-06-11
Anticipated expiration: 2041-03-01
Also published as: CN112953647B

Abstract

The application relates to a quantum communication method, a quantum communication device, a computer device and a storage medium. The method comprises the following steps: after the original information is pre-coded according to a quantum communication protocol, performing decorrelation processing on the pre-coded original information by using a random code word to obtain the pre-coded original information subjected to the decorrelation processing; modulating the quantum according to the pre-coded original information subjected to the decorrelation processing and the quantum communication protocol, and sending the modulated quantum to a second quantum communication end through a quantum channel; and obtaining the position of an effective code word in the pre-coded original information subjected to the disassociation processing and published after the modulated quantum is demodulated by the second quantum communication terminal, and publishing the random code word at the corresponding position and the disassociation processing mode according to the position of the effective code word in the pre-coded original information subjected to the disassociation processing. By adopting the method, the leakage of the associated information between the code words can be reduced, and the safety capacity of quantum communication is enlarged.

Description

Quantum communication method, quantum communication device, computer equipment and storage medium

Technical Field

The present application relates to the field of quantum communication technologies, and in particular, to a quantum communication method, an apparatus, a computer device, and a computer-readable storage medium.

Background

The Wyner's patch channel model provides an instructive guideline for achieving secure communications. The communication capacity of both legal communication parties is the main channel capacity; the maximum information that the eavesdropper can obtain is the capacity of the tap channel or called the eavesdropping capacity, and the security capacity is the main channel capacity minus the tap channel capacity. Wyner wiring channel theory proves that when the information quantity transmitted by the legal two parties in a channel does not exceed the safe capacity, a coding mode exists, which can ensure that the communication error of the legal two parties tends to zero and the information quantity acquired by an eavesdropper tends to zero.

Quantum communication, in which information is directly transmitted through a quantum channel, is a secure communication method with high reliability and security. Under the condition that a quantum channel has loss and noise, in order to ensure the reliability of quantum communication in actual use, the original information needs to be precoded, and precoded codewords often have the capability of resisting high loss, for example, a quantum communication sending end repeatedly sends communication information for many times to ensure that complete information can reach a quantum communication receiving end. Therefore, the number of the code words after pre-coding is greatly increased, the code words have an association relation with each other, and an eavesdropper can obtain available information from the association relation between the code words, so that the security capacity of quantum communication is reduced.

The quanta in the quantum communication process comprise loss quanta, wrongly-measured quanta and successfully-measured quanta; and the code word corresponding to the quantum which is measured wrongly in loss and demodulation is an invalid code word, and the code word corresponding to the quantum which is measured successfully is an effective code word. Therefore, the association relationship among the invalid code words, the association relationship between the valid code words and the invalid code words, and the association relationship among the valid code words may cause information leakage, and the security capacity of quantum communication is reduced.

Disclosure of Invention

In view of the foregoing, it is desirable to provide a quantum communication method, an apparatus, a computer device, and a computer readable storage medium capable of expanding a quantum communication security capacity in response to the above technical problem.

In a first aspect, a quantum communication method is provided, which is applied to a first quantum communication terminal, and includes:

after the original information is pre-coded according to a quantum communication protocol, performing decorrelation processing on the pre-coded original information by using a random code word to obtain the pre-coded original information subjected to the decorrelation processing; modulating the quantum according to the pre-coded original information subjected to the decorrelation processing and a quantum communication protocol, and sending the modulated quantum to a second quantum communication end through a quantum channel; and obtaining the position of an effective code word in the pre-coded original information subjected to the disassociation processing and published after the modulated quantum is demodulated by the second quantum communication terminal, and publishing a random code word corresponding to the position and the disassociation processing mode according to the position of the effective code word in the pre-coded original information subjected to the disassociation processing.

In one embodiment, performing decorrelation processing on the precoded original information by using a random codeword to obtain the precoded original information subjected to decorrelation processing includes:

obtaining the code word length of the pre-coded original information; generating a string of random code words with the length not less than the code word length of the pre-coded original information; and carrying out exclusive or operation or exclusive or operation on each bit of the random code word and each bit of the pre-coded original information code word according to bits to obtain the pre-coded original information subjected to the decorrelation processing.

In one embodiment, modulating a quantum according to the pre-coded original information subjected to the disassociation processing and the quantum communication protocol, and sending the modulated quantum to a second quantum communication terminal through a quantum channel includes:

obtaining a string of single photons which are arranged in a biased and positive random manner; modulating the polarization state of the single photon according to the pre-coded original information subjected to the decorrelation processing and the quantum communication protocol; and sending the modulated single photons to a second quantum communication terminal through the quantum channel.

In a second aspect, a quantum communication method is provided, which is applied to a second quantum communication terminal, and includes:

receiving a modulated quantum sent by a first quantum communication end, demodulating the quantum according to a quantum communication protocol, and obtaining pre-coded original information subjected to decorrelation processing; publishing the position of the effective code word in the pre-coded original information subjected to the disassociation processing; acquiring a random code word of a corresponding position published by a first quantum communication terminal and a disassociation processing mode; the published random code words at the corresponding positions and the disassociation processing mode are published by the first quantum communication terminal responding to the positions of the effective code words in the received pre-encoded original information published by the second quantum communication terminal and subjected to the disassociation processing; restoring effective information in the pre-coded original information subjected to the disassociation processing by using the random code words at the corresponding positions and the disassociation processing mode to obtain restored pre-coded effective information; and decoding the recovered pre-coded effective information by using the quantum communication protocol to obtain the effective information in the original information.

In one embodiment, the method further comprises:

randomly selecting a plurality of quanta which are successfully measured, and publishing the positions of the quanta which are successfully measured; obtaining public code words of the pre-coded original information which is published by the first quantum communication terminal and subjected to the decorrelation processing and corresponds to the positions of the quanta which are measured successfully; the public code word is published by the first quantum communication end in response to the obtained positions of the quanta with successful measurement; comparing whether the code words represented by the quantum with successful measurement are the same as the public code words to obtain a comparison result; calculating the bit error rate of the quantum channel according to the comparison result; and if the error rate exceeds a preset value, suspending communication.

In one embodiment, the method further comprises:

calculating the loss rate of the quantum channel according to the detection result; if the loss rate exceeds a preset value, the communication is suspended.

In a third aspect, there is provided a quantum communication device for a first quantum communication terminal, the device comprising:

the decorrelation module is used for performing decorrelation processing on the pre-coded original information by using a random code word after the original information is pre-coded according to a quantum communication protocol to obtain the pre-coded original information subjected to the decorrelation processing;

the modulation sending module is used for modulating the quantum according to the pre-coded original information subjected to the disassociation processing and the quantum communication protocol, and sending the modulated quantum to a second quantum communication terminal through a quantum channel;

and the first publishing module is used for acquiring the position of an effective code word in the pre-coded original information subjected to the disassociation processing and published after the modulated quantum is demodulated by the second quantum communication terminal, and publishing the random code word and the disassociation processing mode corresponding to the position according to the position of the effective code word in the pre-coded original information subjected to the disassociation processing.

In a fourth aspect, there is provided a quantum communication device for a second quantum communication terminal, the device comprising:

the demodulation module is used for receiving the modulated quanta sent by the first quantum communication terminal and demodulating the modulated quanta according to a quantum communication protocol to obtain pre-coded original information subjected to decorrelation processing;

a second publishing module, configured to publish a position of an effective codeword in the pre-coded original information subjected to the decorrelation processing;

the acquisition module is used for acquiring the random code words at the corresponding positions published by the first quantum communication terminal and the way of disassociation processing; the published random code words at the corresponding positions and the disassociation processing mode are published by the first quantum communication terminal responding to the positions of the effective code words in the received pre-encoded original information published by the second quantum communication terminal and subjected to the disassociation processing;

a restoring module, configured to restore effective information in the pre-coded original information subjected to the decorrelation processing by using the random codeword at the corresponding position and the decorrelation processing manner, to obtain restored pre-coded effective information;

and the decoding module is used for decoding the recovered pre-coded effective information by using the quantum communication protocol to obtain the effective information in the original information.

In a fifth aspect, there is provided a computer device comprising a memory and a processor, the memory storing a computer program which, when executed by the processor, implements the quantum communication method according to any of the first aspects described above, or which, when executed by the processor, implements the quantum communication method according to any of the second aspects described above.

A sixth aspect provides a computer readable storage medium having stored thereon a computer program which, when executed by a processor, implements a quantum communication method as described in any of the first aspects above, or which, when executed by a processor, implements a quantum communication method as described in any of the second aspects above.

According to the quantum communication method, the device, the computer equipment and the storage medium, the pre-coded original information comprises a large number of code words, the code words and the code words have an incidence relation, and an eavesdropper can obtain available information from the incidence relation between the code words and the code words, so that communication is unsafe, so that the random code words are used for performing disassociation processing on the pre-coded original information to obtain the pre-coded original information subjected to disassociation processing; modulating the quantum according to the pre-coded original information subjected to the decorrelation processing and a quantum communication protocol, and sending the modulated quantum to a second quantum communication end through a quantum channel; and obtaining the position of an effective code word in the pre-coded original information subjected to the disassociation processing and published after the modulated quantum is demodulated by the second quantum communication terminal, and publishing a random code word corresponding to the position and the disassociation processing mode according to the position of the effective code word in the pre-coded original information subjected to the disassociation processing. Because the original information after precoding is subjected to the disassociation processing, and the first quantum communication terminal only discloses the random code words at the positions corresponding to the valid code words and does not disclose the random code words corresponding to the invalid code words, no association relationship exists between the invalid code words and the valid code words after the disassociation processing, and no information can be obtained from the association relationship even if an eavesdropper overhears the part of the code words. The quantum communication security capacity is the main channel capacity minus the eavesdropping capacity, the main channel capacity is unchanged, and since an eavesdropper cannot obtain available information from the association relationship between the invalid code words and the association relationship between the invalid code words and the valid code words, the eavesdropping capacity is reduced, so that the security capacity of the quantum communication is enlarged.

Drawings

FIG. 1 is a diagram of an application environment of a quantum communication method in one embodiment;

FIG. 2 is a flow diagram of a method of quantum communication in one embodiment;

fig. 3 is a schematic flow chart illustrating a technical process of performing decorrelation processing on the pre-coded original information by using a random codeword to obtain the pre-coded original information subjected to decorrelation processing in one embodiment;

fig. 4 is a flowchart illustrating a technical process of modulating a quantum according to the pre-coded original information of the disassociation processing and the quantum communication protocol and sending the modulated quantum to a second quantum communication terminal through a quantum channel in one embodiment;

FIG. 5 is a flow diagram illustrating a method of quantum communication in one embodiment;

FIG. 6 is a flow chart illustrating a quantum communication method according to another embodiment;

FIG. 7 is a flow chart illustrating a quantum communication method according to another embodiment;

FIG. 8 is a flow diagram illustrating a method of quantum communication in one embodiment;

FIG. 9 is a block diagram of a quantum communication device in one embodiment;

fig. 10 is a block diagram showing the structure of a quantum communication device in another embodiment;

FIG. 11 is a diagram illustrating an internal structure of a computer device in one embodiment.

Detailed Description

In order to make the objects, technical solutions and advantages of the present application more apparent, the present application is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.

The quantum communication method provided by the application can be applied to the application environment shown in fig. 1. The first quantum communication terminal 102 includes a laser 104, a first modulator 106, and a first device with computing capability 108, where the first device with computing capability 108 is connected to the laser 104 and the first modulator 106, and the laser 104 is connected to the first modulator 106; the second quantum communication terminal 110 comprises a second modulator 112, a detector 114 and a second computing-capable device 116, wherein the second computing-capable device 116 is connected to the second modulator 112 and the detector 114, and the second modulator 112 is connected to the detector 114. The first computing-capable device 108 and the second computing-capable device 116 may be, but are not limited to, a server, a personal computer, a laptop, a smartphone, a tablet, and a portable wearable device. Establishing a service channel between the first computing-capable device 108 and the second computing-capable device 116, the service channel being used for publication of small amounts of information; a quantum channel is established between the first modulator 106 and the second modulator 112, and the quantum channel is used for modulated quantum transmission.

In one embodiment, as shown in fig. 2, a quantum communication method is provided, which is described by taking the method as an example applied to the first quantum communication terminal in fig. 1, and includes the following steps:

step 202, after the original information is pre-coded according to the quantum communication protocol, the first device with computing capability of the first quantum communication terminal performs disassociation processing on the pre-coded original information by using the random code word, so as to obtain the pre-coded original information which is subjected to disassociation processing.

In an embodiment of the present application, the quantum communication protocol refers to a set of rules agreed in advance for both sides of quantum communication to complete communication, and the items agreed in advance by the quantum communication protocol may include a precoding manner of original information, selectable basis vectors in the quantum modulation and demodulation process, and a corresponding relationship between a vector under each basis vector and a codeword. The original information refers to information which needs to be communicated between the first quantum communication end and the second quantum communication end, and because quantum channels have loss and noise, the original information is generally subjected to precoding to resist high loss. According to different quantum communication protocols, the specific precoding mode is different, and generally precoding includes homogenization of original information, dilution of original information, error correction coding and spread spectrum coding of the original information. The homogenization of the original information refers to that each bit of information transmitted after the original information is pre-coded is uniformly distributed on a pre-coded code word; the original information dilution means that irrelevant information is added into the original information, so that the proportion of the original information in the pre-coded code words is reduced; the error correction coding refers to a coding form that the second quantum communication terminal can find errors caused by transmission and correct after receiving the pre-coded original information; the error correction coding may be low density parity check code (LDPC) error correction coding. Spread spectrum coding means that the information after error correction coding is copied for a plurality of times, so that the original information after precoding contains a plurality of original information. Although the quantum channel has the characteristic of high loss, the process of information homogenization, dilution, error correction and spread spectrum enables the pre-coded original information to be lost in the transmission process or have error measurement in the demodulation process of the second quantum communication end, the second quantum communication end can still receive effective information, and the quanta of the first quantum communication end and the second quantum communication end in the communication process comprise loss quanta, wrongly-measured quanta and successfully-measured quanta; the lost quanta and the code words corresponding to the quanta which are measured wrongly during demodulation are invalid code words, and the invalid code words are binary representation forms of invalid information. And the code word corresponding to the quantum which is successfully measured is a valid code word, and the valid code word is a binary representation form of valid information. The error measurement means that the basis vector used when the second quantum communication terminal demodulates the quantum is different from the basis vector used when the first quantum communication terminal modulates the quantum.

Although precoding can bring the advantage of resisting high loss, more redundant information is added, if an eavesdropper acquires a part of code words in the process of monitoring the quantum channel, the usable information can be acquired according to the incidence relation among the part of code words, and thus information leakage is caused.

Therefore, the pre-coded original information needs to be subjected to decorrelation processing, the pre-coded original information is firstly represented in a binary form, the decorrelation processing means that information association between code words is removed, so that an eavesdropper cannot obtain the original information by analyzing fragments of a plurality of pieces of the original information, the decorrelation mode is that a string of random code words in the binary form and the pre-coded original information code words are subjected to bitwise logical operation which can be reversely deduced, the reversely deduced logical operation means that a and B perform logical operation to obtain C, and the operation for deducing a can be reversely deduced under the condition that C and B are known. In a simple example, the codeword of the pre-coded original information is 10011001, the random codeword is 0101, and the logical operation is an exclusive-or operation, so that the decorrelated pre-coded original information is 11001001. When the length of the random code word is smaller than the length of the pre-coded original information code word, for example, when the length of the random code word is n, the random code word is utilized to perform disassociation processing from the first bit of the pre-coded original information code word, and the first bit to the nth bit of the pre-coded original information code word can be processed, so that disassociation of an information part between invalid code words can be realized only, but the time required by disassociation operation is shortened; when the length of the random code word is larger than or equal to the length of the original information code word after precoding, information disassociation among all invalid code words can be achieved.

Step 204, the first modulator of the first quantum communication end modulates the quantum according to the pre-coded original information of the disassociation processing and the quantum communication protocol, and sends the modulated quantum to the second modulator of the second quantum communication end through a quantum channel.

As described above, the first quantum communication terminal and the second quantum communication terminal agree in advance on the selectable basis vectors and the corresponding relationship between the vector and the codeword under each basis vector through the quantum communication protocol, in an embodiment of the present application, a laser of the first quantum communication terminal first sends, to a modulator of the first quantum communication terminal, a quantum whose number of quanta is the same as the length of the precoded original information codeword subjected to the decorrelation processing. Each bit decorrelates the code word of the precoded original information processed to correspond to an unmodulated quantum. During modulation, a first modulator at a first quantum communication end randomly selects a basis vector from selectable basis vectors, and modulates the quantum according to the corresponding code word and the corresponding relation between the basis vector and the code word. And if the code word of the pre-coded original information subjected to the decorrelation processing is 1 and the basis vector is randomly selected to be a horizontal basis vector and a vertical basis vector, modulating the corresponding quantum to be in a vertical state.

In step 206, the first device with computing power at the first quantum communication end obtains the position of the effective codeword in the pre-encoded original information after decorrelation processing published after the second quantum communication end demodulates the modulated quantum, and publishes the random codeword at the corresponding position and the way of decorrelation processing according to the position of the effective codeword in the pre-encoded original information after decorrelation processing.

In an embodiment of the present application, the second modulator of the second quantum communication end receives the modulated quantum sent by the first modulator of the first quantum communication end, and demodulates the quantum first, where the demodulation process is as follows: the quantum communication protocol appoints selectable basis vectors, a modulator of the second quantum communication end randomly selects one basis vector from the selectable basis vectors for each received quantum, a detector of the second quantum communication end detects the quantum according to the randomly selected basis vector, when the selected basis vector is the same as the basis vector used by the quantum when the first modulator of the first quantum communication end is modulated and a detection result exists, the measurement is successful, and the other situations are measurement failures. If the quantum is lost in the transmission process, the detector cannot be triggered, and the lost quantum has no detection result. Each quantum which is successfully measured represents an effective code word, and an effective code word in the pre-coded original information which is subjected to the disassociation processing is obtained according to the quantum which is successfully measured, for example, for an observer facing the first modulator and the second modulator, the quantum communication protocol stipulates selectable basis vectors as a horizontal basis vector, a vertical basis vector, a left oblique basis vector, a right oblique basis vector, a horizontal state, a left oblique state, a vertical state, a right oblique state, and a known polarization state of the quantum which is successfully measured as a vertical state and a right oblique state in advance, so that the effective code word in the pre-coded original information which is subjected to the disassociation processing is known to be 11. And the positions of the successfully measured quanta in all the quanta are the positions of the effective code words in the pre-coded original information subjected to the disassociation processing. If the second modulator of the second quantum communication end receives 10 quanta in sequence, wherein the 1 st quanta and the 5 th quanta are quanta which are successfully measured, the positions of effective code words in the pre-coded original information after the decorrelation processing are 1 and 5. The second equipment with computing power of the second quantum communication terminal publishes the position of the effective code word in the pre-coded original information subjected to the disassociation processing through the service channel, after the first equipment with computing power of the first quantum communication terminal obtains the position of the effective code word, the random code word at the corresponding position is published through the service channel, and the random code words at the rest positions can be kept secret permanently. As described above, the disassociation is a bit-wise derivable logical operation using a string of random code words with the pre-encoded original information code words. When the first quantum communication terminal discloses the random code word at the corresponding position, the specific logic operation capable of reverse derivation is also disclosed.

In the quantum communication method, the pre-coded original information contains a large number of code words, the code words and the code words have an incidence relation, and an eavesdropper can obtain available information from the incidence relation between the code words and the code words, so that communication is unsafe, so that the pre-coded original information is subjected to decorrelation processing by using random code words to obtain the pre-coded original information subjected to decorrelation processing; modulating the quantum according to the pre-coded original information subjected to the decorrelation processing and a quantum communication protocol, and sending the modulated quantum to a second quantum communication end through a quantum channel; and obtaining the position of an effective code word in the pre-coded original information subjected to the disassociation processing and published after the modulated quantum is demodulated by the second quantum communication terminal, and publishing a random code word corresponding to the position and the disassociation processing mode according to the position of the effective code word in the pre-coded original information subjected to the disassociation processing. Because the original information after precoding is subjected to the disassociation processing, and the first quantum communication terminal only discloses the random code words at the positions corresponding to the valid code words and does not disclose the random code words corresponding to the invalid code words, no association relationship exists between the invalid code words and the valid code words after the disassociation processing, and no information can be obtained from the association relationship even if an eavesdropper overhears the part of the code words. The quantum communication security capacity is the main channel capacity minus the eavesdropping capacity, the main channel capacity is unchanged, and since an eavesdropper cannot obtain available information from the association relationship between the invalid code words and the association relationship between the invalid code words and the valid code words, the eavesdropping capacity is reduced, so that the security capacity of the quantum communication is enlarged.

In an embodiment, as shown in fig. 3, performing decorrelation processing on the pre-coded original information by using a random codeword, to obtain the pre-coded original information after the decorrelation processing includes:

step 302, a first device with computing power at the first quantum communication end obtains the codeword length of the pre-coded original information.

As described above, the precoded original information is obtained, the precoded original information codeword refers to the precoded original information represented in a binary form, the first quantum communication terminal counts the codeword length of the precoded original information, the codeword length refers to the number of codeword bits, and if the codeword of the precoded original information is 1000, the codeword length of the precoded original information is 4.

Step 304, the first computing-capable device of the first quantum communication end generates a string of random code words with a length not less than the code word length of the pre-coded original information.

Step 306, the first device with computing power of the first quantum communication end performs an exclusive or operation or an exclusive or operation on each bit of the random code word and each bit of the pre-coded original information code word according to bits, so as to obtain the pre-coded original information subjected to the decorrelation processing.

In an embodiment of the application, the first quantum communication terminal performs a bitwise xor operation on each bit of the generated random code word and each bit of the pre-coded original information code word, if the random code word is 1100, the pre-coded original information code word is 1001, performs a bitwise xor operation on 1100 and 1001, and an xor result is 0101, the pre-coded original information subjected to the decorrelation processing is 0101.

In another embodiment of the present application, the first quantum communication terminal performs a bitwise exclusive nor operation on each bit of the generated random code word and each bit of the pre-encoded original information code word, where the random code word is 1100, the pre-encoded original information code word is 1001, and the bitwise exclusive nor operation is performed on 1100 and 1001, and the exclusive nor result is 1010.

In this embodiment, the length of the random codeword is not less than the length of the codeword of the pre-coded original information, so that all codewords of the pre-coded original information can be disassociated by using the random codeword, and the first quantum communication terminal only publishes the random codeword at the position corresponding to the valid codeword, so that all invalid codewords are disassociated codewords. An eavesdropper cannot obtain available information from the association relationship between the invalid code words and the association relationship between the invalid code words and the valid code words, so that the quantum communication security capacity can be maximized by applying the method in the embodiment.

In one embodiment, as shown in fig. 4, modulating a quantum according to the pre-coded original information of the disassociation processing and the quantum communication protocol, and sending the modulated quantum to the second quantum communication end through a quantum channel includes:

step 402, a first modulator at a first quantum communication end obtains a string of single photons with randomly arranged polarization.

In one embodiment of the present application, the quantum may be a single photon. The laser of the first quantum communication end emits a string of randomly polarized single photons to the modulator of the first quantum communication end for quantum communication, and in a specific embodiment, the string of randomly polarized single photons can be randomly polarized in horizontal and vertical directions and obliquely polarized single photons.

And step 404, the first modulator of the first quantum communication end modulates the polarization state of the single photon according to the pre-coded original information subjected to the decorrelation processing and the quantum communication protocol.

As described above, for each quantum, the first modulator of the first quantum communication terminal randomly selects one basis vector from the selectable basis vectors to modulate the quantum. In an embodiment of the application, the selectable basis vectors are agreed in advance by the first quantum communication terminal and the second quantum communication terminal through a quantum communication protocol to be horizontal and vertical basis vectors and left-oblique and right-oblique basis vectors, wherein the single photons in the horizontal state and the left-oblique state represent 0, and the single photons in the vertical state and the right-oblique state represent 1. And when modulating, the first modulator firstly randomly selects a basis vector and modulates the single photon according to the corresponding code word and the corresponding relation between the basis vector and the code word. And if the code word of the pre-coded original information subjected to the decorrelation processing is 1 and the basis vector is randomly selected to be a horizontal basis vector and a vertical basis vector, modulating the corresponding single photon into a vertical state.

And 406, the first modulator of the first quantum communication terminal sends the modulated single photon to the second quantum communication terminal through the quantum channel.

In one embodiment, the computing-capable device of the second quantum communication terminal publishes the randomly selected positions of the plurality of successfully measured quanta and the code words represented by the plurality of successfully measured quanta through the service channel. The device with computing capability of the first quantum communication terminal receives the randomly selected positions of the multiple quanta which are successfully measured through the service channel, and publishes the public code words of the pre-coded original information which is subjected to the decorrelation processing and corresponds to the positions through the service channel according to the randomly selected positions of the multiple quanta which are successfully measured. After receiving the code words represented by the multiple quanta which are measured successfully, the first equipment with computing capability of the first quantum communication end compares whether the code words represented by the multiple quanta which are measured successfully are the same as the public code words according to the position, and records the number of the different code words; calculating the proportion of the number of different code words in the total number of the public code words, wherein the proportion is the error rate; comparing whether the error rate exceeds a preset error rate threshold, and if the error rate exceeds the preset error rate threshold, suspending communication; and if the error rate does not exceed the preset error rate threshold, continuing the communication. The preset error rate threshold is calculated according to the error correction capability and the confidentiality capability of the pre-coding, and when the error correction capability and the confidentiality capability of the pre-coding are higher, the preset error rate threshold is higher.

In the embodiment, if the quantum channel has the error code that is possibly caused by eavesdroppers stealing information, the security of the quantum channel is insufficient when the error rate is too high, and information leakage may be caused by using the quantum channel for communication; in addition, the quantum communication corrects error code words in the received information through error correction coding, and when the number of error codes exceeds the capability of the error correction coding to correct errors, both sides of the quantum communication cannot carry out normal communication. Therefore, the first quantum communication terminal carries out error rate calculation according to the contents disclosed by the first quantum communication terminal and the second quantum communication terminal, and communication is suspended if the error rate exceeds a preset error rate threshold value. The method for quantum communication can enlarge the safety capacity on the premise of ensuring the safety of the quantum channel and the normal communication of both sides of the quantum communication.

As shown in fig. 5, a quantum communication method is provided, which is exemplified by the method applied to the second quantum communication terminal in fig. 1, and includes the following steps:

step 502, the second modulator of the second quantum communication end receives the modulated quantum sent by the first modulator of the first quantum communication end, and demodulates the quantum according to the quantum communication protocol to obtain the pre-coded original information subjected to the decorrelation processing.

As described above, the first quantum communication terminal modulates the quantum according to the pre-coded original information of the disassociation processing, and sends the quantum to the second quantum communication terminal. The second quantum communication terminal demodulates the quantum after receiving the quantum, and the specific technical process of demodulation is detailed in the above embodiments and is not described here again.

Step 504, the second computing-capable device of the second quantum communication end publishes the location of the valid codeword in the pre-coded original information after the disassociation processing through the service channel.

The technical process for publishing the position of the valid codeword in the pre-coded original information after the disassociation processing is detailed in the above embodiment, and is not repeated here.

Step 506, a second device with computing capability of the second quantum communication terminal obtains the random code word at the corresponding position published by the first quantum communication terminal through the service channel and the disassociation processing mode; the published random code word corresponding to the position and the disassociation processing mode are published by the first quantum communication terminal responding to the position of the effective code word in the received pre-encoded original information published by the second quantum communication terminal and subjected to the disassociation processing.

In an embodiment of the application, a first device with computing capability of a first quantum communication end publishes a random codeword of a corresponding location and a disassociation processing mode through a service channel, and a second device with computing capability of a second quantum communication end can obtain the random codeword of the corresponding location and the disassociation processing mode through the service channel after the first device with computing capability of the first quantum communication end publishes the random codeword.

And step 508, restoring effective information in the pre-coded original information subjected to the disassociation processing by using the random code word at the corresponding position and the disassociation processing mode by using a second device with computing capability of the second quantum communication terminal to obtain the restored pre-coded effective information.

As described above, the disassociation process is performed by performing a bit-wise inversely derivable logical operation on a string of binary random code words and the pre-encoded original code words. In an embodiment of the present application, the valid codeword is a binary representation form of the valid information, after a second device with computing capability at the second quantum communication end obtains the valid codeword in the pre-coded original information subjected to the decorrelation processing, the random codeword at the corresponding position, and the decorrelation processing manner, the second quantum communication end performs logical operation on the random codeword and the valid codeword at the corresponding position according to bits, so as to obtain the recovered pre-coded valid information. If the effective information in the pre-coded original information after the disassociation processing is 1110, the random code word at the corresponding position is 0001, and the logical operation of the disassociation processing is the xor operation, the effective information in the pre-coded original information after the disassociation processing and the random code word at the corresponding position are subjected to the xor operation in bits when the recovered pre-coded effective information is calculated, and the recovered pre-coded effective information is 1111.

Step 510, the second computing-capable device of the second quantum communication end decodes the recovered precoded effective information by using the quantum communication protocol to obtain the effective information in the original information.

As described above, the first quantum communication terminal and the second quantum communication terminal agree on a precoding mode in advance through a quantum communication protocol, and the second quantum communication terminal decodes the restored precoded effective information according to a specific precoding mode to obtain the effective information in the original information. In an embodiment of the application, the precoding manner includes LDPC encoding and spread spectrum encoding, according to a quantum communication protocol, a second device with computing capability at a second quantum communication end learns the number n of times that original information after LDPC encoding is copied in the spread spectrum encoding, and divides recovered precoded effective information into n segments, where each segment is effective information in the original information after LDPC encoding. And performing LDPC decoding on the effective information in the original information after one section of LDPC coding to obtain the effective information in the original information.

In the quantum communication method, the precoded original information comprises a large number of codewords, an incidence relation exists between the codewords, and an eavesdropper can obtain available information from the incidence relation between the codewords, so that communication is unsafe, therefore, the precoded original information is subjected to decorrelation processing by the first quantum communication terminal, the precoded original information subjected to the decorrelation processing is used for modulating quanta, the modulated quanta sent by the first quantum communication terminal are received by the second quantum communication terminal, and the modulated quanta are demodulated according to a quantum communication protocol, so that the precoded original information subjected to the decorrelation processing is obtained; in the demodulation process, each quantum which is measured successfully corresponds to an effective code word of the pre-coded original information which is subjected to the disassociation processing, the position of the quantum which is measured successfully in all the quanta is the position of the effective code word of the pre-coded original information which is subjected to the disassociation processing in the pre-coded original information which is subjected to the disassociation processing, and the position of the effective code word in the pre-coded original information which is subjected to the disassociation processing is published; acquiring a random code word of a corresponding position published by a first quantum communication terminal and a disassociation processing mode; restoring effective information in the pre-coded original information subjected to the disassociation processing by using the random code words at the corresponding positions and the disassociation processing mode to obtain restored pre-coded effective information; and decoding the recovered pre-coded effective information by using the quantum communication protocol to obtain the effective information in the original information. Because the first quantum communication end does not disclose the random code words corresponding to the invalid code words, no association relationship exists between the invalid code words and the invalid code words after the association processing, no association relationship exists between the invalid code words and the valid code words, and an eavesdropper cannot obtain available information from the association relationship even though the eavesdropper overhears the part of the code words. The quantum communication security capacity is the main channel capacity minus the eavesdropping capacity, the main channel capacity is unchanged, and since an eavesdropper cannot obtain available information from invalid information obtained from the incidence relation between invalid code words and the incidence relation between the invalid code words and valid code words, the eavesdropping capacity is reduced, and the security capacity of quantum communication is enlarged.

In one embodiment, as shown in fig. 6, the quantum communication method further includes:

step 602, the second computing-capable device of the second quantum communication end randomly selects a plurality of successfully measured quanta, and publishes the positions of the successfully measured quanta.

As described above, the basis vector selected when the second quantum communication terminal demodulates is the same as the basis vector used when the first modulator of the first quantum communication terminal modulates the quantum, and the quantum with the detection result is the quantum with successful measurement. In an embodiment of the present application, the second computing-capable device at the second quantum communication end randomly selects a plurality of successfully measured quanta from all the successfully measured quanta, and the randomly selecting the number of the successfully measured quanta is such that the bit error rate has negligible fluctuation in local part during statistics; the second computing-capable device of the second quantum communication terminal publishes the position of the randomly selected plurality of successfully measured quanta in all quanta received by the second modulator of the second quantum communication terminal through the service channel.

In step 604, the second computing-capable device of the second quantum communication end obtains the public codeword of the pre-coded original information, which is published by the first computing-capable device of the first quantum communication end and corresponds to the positions of the successfully measured quanta, of the pre-coded original information after the disassociation processing, and the public codeword is published by the first computing-capable device of the first quantum communication end responding to the obtained positions of the successfully measured quanta.

In an embodiment of the present application, a first computing-capable device at a first quantum communication end obtains, through a service channel, a position of a plurality of successfully-measured quanta published by a second computing-capable device at a second quantum communication end in all quanta, and publishes code words of pre-coded original information subjected to decorrelation processing on the position, where the code words are referred to as public code words. And a second computing-capable device of the second quantum communication terminal obtains the public code word through the service channel. For example, the positions of the successfully measured quanta in all quanta are 1, 3, and 4, the 1 st bit of the pre-coded original information subjected to the decorrelation processing is the 3 rd bit and the 4 th bit are corresponding code words 1, 0, and 0, respectively, then the public code words are 1, 0, and the first device with computing capability of the first quantum communication terminal publishes 1, 0, and 0 through the service channel.

Step 606, the second device with computing power of the second quantum communication terminal compares whether the code word represented by the measured successfully measured quanta is the same as the public code word, and obtains a comparison result.

In an embodiment of the present application, a second device with computing capability at a second quantum communication end compares a codeword represented by a quantum whose measurement is successful at a corresponding position with a pre-coded original information codeword subjected to decorrelation processing one by one, and if the codewords are different, the codeword is recorded as an error code, and the comparison result is the number of the error codes.

In step 608, the second device with computing capability of the second quantum communication terminal computes the bit error rate of the quantum channel according to the comparison result.

In an embodiment of the present application, the number of erroneous measurements, i.e. the number of bit errors, in the successfully measured quanta can be obtained according to the comparison result as described above. The ratio of the number of the error codes to the number of the randomly selected quantum which is successfully measured is the bit error rate of the quantum channel.

In step 610, if the bit error rate exceeds a preset value, the communication is suspended.

In an embodiment of the application, if an eavesdropper in the quantum channel steals information, error codes may be caused, so that when the error code rate is too high, the security of the quantum channel is insufficient, and information leakage may be caused by communication using the quantum channel; in addition, the quantum communication corrects error code words in the received information through error correction coding, and when the number of error codes exceeds the capability of the error correction coding to correct errors, both sides of the quantum communication cannot carry out normal communication. The preset value may be a preset error rate threshold, the preset error rate threshold is calculated according to the error correction capability and the security capability of the precoding, and when the error correction capability and the security capability of the precoding are larger, the preset error rate threshold is larger. When the error rate exceeds a preset value, the safety of the quantum channel is insufficient, the first quantum communication end and the second quantum communication end cannot normally communicate, and the communication is suspended.

In this embodiment, the second quantum communication terminal calculates the bit error rate of the quantum channel first, and continues to perform communication when the bit error rate of the quantum channel does not exceed a preset value; if the bit error rate of the quantum channel exceeds a preset value, the communication is suspended; the method for quantum communication can enlarge the safety capacity on the premise of ensuring the safety of the quantum channel and the normal communication of both sides of the quantum communication.

In one embodiment, as shown in fig. 7, the quantum communication method further includes:

and step 702, the second device with computing capability of the second quantum communication terminal computes the loss rate of the quantum channel according to the detection result.

As described above, the second quantum communication terminal detects the quantum by using the detector, and if the quantum is lost in the transmission process, the detector cannot be triggered, and the lost quantum has no detection result. In one embodiment of the present application, the loss rate may be calculated as a ratio of the number of non-detected quanta to the total number of quanta.

In step 704, if the loss rate exceeds a predetermined value, the communication is suspended.

In an embodiment of the application, the spread spectrum coding copies original information for many times, and when the loss rate of a quantum channel is too high, a large amount of information is lost, so that a first quantum communication end and a second quantum communication end cannot receive a section of complete original information, thereby affecting normal communication of both quantum communication ends; the preset value may be a preset loss rate threshold, where the preset loss rate is calculated according to the loss-tolerant power of the spread spectrum code in the precoding, and when the loss-tolerant power of the spread spectrum code in the precoding is larger, the preset loss rate threshold is larger. And when the loss rate exceeds a preset value, the first quantum communication terminal and the second quantum communication terminal cannot normally communicate, and the communication is suspended.

In this embodiment, the loss of the quantum channel is first calculated, and when the loss of the quantum channel does not exceed a preset value, communication is continued; if the loss of the quantum channel exceeds a preset value, the communication is suspended; the method for quantum communication can enlarge the safety capacity on the premise of ensuring the normal communication of both sides of quantum communication.

As shown in fig. 8, in order to make readers easily understand the technical solution provided by the embodiment of the present application, in the embodiment of the present application, a quantum communication method provided by the embodiment of the present application will be briefly described in a form that a first quantum communication terminal and a second quantum communication terminal interact with each other, where a process of security and normal communication analysis refers to calculating an error rate and a loss rate, and if the error rate or the loss rate exceeds a preset value, communication is suspended.

Step 802, after the first quantum communication terminal performs precoding on the original information according to the quantum communication protocol, the first quantum communication terminal performs disassociation processing on the precoded original information by using the random code word to obtain the precoded original information subjected to disassociation processing.

Step 804, the first quantum communication terminal modulates the quantum according to the pre-coded original information of the disassociation processing and the quantum communication protocol, and sends the modulated quantum to the second quantum communication terminal through a quantum channel.

Step 806, the second quantum communication terminal receives the modulated quantum, and demodulates the modulated quantum according to the quantum communication protocol to obtain the pre-coded original information subjected to the decorrelation processing.

And 808, randomly selecting a plurality of successfully-measured quanta by the second quantum communication terminal, and publishing the positions of the plurality of successfully-measured quanta.

Step 810, the first quantum communication terminal obtains the positions of the multiple successfully measured quanta, and publishes the public code words of the pre-coded original information which is subjected to the decorrelation processing and corresponds to the positions of the multiple successfully measured quanta.

In step 812, the second quantum communication terminal obtains the public codeword, and compares whether the codewords represented by the multiple measured quanta are the same as the public codeword to obtain a comparison result.

And 814, the second quantum communication terminal calculates the bit error rate of the quantum channel according to the comparison result.

Step 816, the second quantum communication terminal determines that if the bit error rate exceeds a preset value, communication is suspended; and if the error rate does not exceed the preset value, continuing to carry out communication.

Step 818, the second quantum communication terminal publishes the position of the valid codeword in the pre-coded original information after the disassociation processing through the service channel.

And 820, the first quantum communication terminal obtains the position of the effective code word in the pre-coded original information subjected to the disassociation processing, and publishes the random code word at the corresponding position and the disassociation processing mode according to the position of the effective code word in the pre-coded original information subjected to the disassociation processing.

Step 822, the second quantum communication terminal obtains the random code word at the corresponding position and the disassociation processing mode, and recovers the effective information in the pre-coded original information after the disassociation processing according to the random code word at the corresponding position and the disassociation processing mode to obtain the recovered pre-coded effective information.

Step 824, the second quantum communication terminal decodes the recovered pre-coded effective information by using the quantum communication protocol to obtain effective information of the original information.

It should be understood that although the various steps in the flow charts of fig. 2-8 are shown in order as indicated by the arrows, the steps are not necessarily performed in order as indicated by the arrows. The steps are not performed in the exact order shown and described, and may be performed in other orders, unless explicitly stated otherwise. Moreover, at least some of the steps in fig. 2-8 may include multiple steps or multiple stages, which are not necessarily performed at the same time, but may be performed at different times, which are not necessarily performed in sequence, but may be performed in turn or alternately with other steps or at least some of the other steps.

In one embodiment, as shown in fig. 9, there is provided a quantum communication device 900 applied to a first quantum communication terminal, the device comprising: disassociation module 902, modulation sending module 904 and first publishing module 906, wherein:

and a disassociation module 902, configured to perform disassociation processing on the precoded original information by using a random codeword after the original information is precoded according to the quantum communication protocol, so as to obtain the precoded original information subjected to disassociation processing.

A modulation sending module 904, configured to modulate the quantum according to the pre-coded original information subjected to the disassociation processing and the quantum communication protocol, and send the modulated quantum to the second quantum communication end through a quantum channel.

A first publishing module 906, configured to obtain a position of an effective codeword in the pre-coded original information subjected to the disassociation processing and published after the modulated quantum is demodulated by the second quantum communication terminal, and publish the random codeword at the corresponding position and a disassociation processing manner according to the position of the effective codeword in the pre-coded original information subjected to the disassociation processing.

In an embodiment, the disassociation module 902 is specifically configured to obtain a codeword length of the pre-encoded original information; generating a string of random code words with the length not less than the code word length of the pre-coded original information; and carrying out exclusive or operation or exclusive or operation on each bit of the random code word and each bit of the pre-coded original information code word according to bits to obtain the pre-coded original information subjected to the decorrelation processing.

In one embodiment, the modulation and transmission module 904 is specifically configured to obtain a string of randomly polarized single photons; modulating the polarization state of the single photon according to the pre-coded original information subjected to the decorrelation processing and the quantum communication protocol; and sending the modulated single photons to a second quantum communication terminal through the quantum channel.

In one embodiment, as shown in fig. 10, there is provided a quantum communication device 1000 applied to a second quantum communication terminal, the device comprising: a demodulation module 1002, a second publication module 1004, and an acquisition module 1006, a recovery module 1008, and a decoding module 1010. Wherein:

the demodulation module 1002 is configured to receive a quantum transmitted by the first quantum communication terminal after modulation, and demodulate the modulated quantum according to a quantum communication protocol to obtain precoded original information subjected to decorrelation processing.

A second publishing module 1004, configured to publish the location of the valid codeword in the pre-encoded original information after the disassociation processing.

An obtaining module 1006, configured to obtain a random codeword at a corresponding position published by a first quantum communication end and a disassociation processing manner; the published random code word corresponding to the position and the disassociation processing mode are published by the first quantum communication terminal responding to the position of the effective code word in the received pre-encoded original information published by the second quantum communication terminal and subjected to the disassociation processing.

A restoring module 1008, configured to restore effective information in the pre-coded original information subjected to the disassociation processing by using the random codeword at the corresponding position and the disassociation processing manner, to obtain restored pre-coded effective information.

The decoding module 1010 is configured to decode the recovered precoded valid information by using the quantum communication protocol, so as to obtain valid information in the original information.

In an embodiment, another quantum communication apparatus is provided, which includes, in addition to the modules of the quantum communication apparatus 1000, optionally, a selection module, a codeword obtaining module, a comparison module, a first calculation module, and a first judgment module.

The selection module is used for randomly selecting a plurality of quanta which are successfully measured and publishing the positions of the quanta which are successfully measured.

And the code word obtaining module is used for obtaining a public code word of the pre-coded original information which is published by the first quantum communication terminal and subjected to the decorrelation processing and corresponds to the positions of the plurality of successfully-measured quanta, and the public code word is published by the first quantum communication terminal in response to the obtained positions of the plurality of successfully-measured quanta.

And the comparison module is used for comparing whether the code words represented by the plurality of measured successful quanta are the same as the public code words or not to obtain a comparison result.

And the first calculation module is used for calculating the bit error rate of the quantum channel according to the comparison result.

And the first judgment module is used for suspending communication when the error rate exceeds a preset value.

In one embodiment, another quantum communication device is provided, which includes, in addition to the modules of the quantum communication device 1000, optionally, a second calculation module and a second judgment module.

The second calculation module is used for calculating the loss rate of the quantum channel according to the detection result.

The second judging module is used for suspending communication when the loss rate exceeds a preset value.

For specific limitations of the quantum communication device, reference may be made to the above limitations of the quantum communication method, which are not described herein again. The respective modules in the quantum communication device described above may be implemented in whole or in part by software, hardware, and a combination thereof. The modules can be embedded in a hardware form or independent from a processor in the computer device, and can also be stored in a memory in the computer device in a software form, so that the processor can call and execute operations corresponding to the modules.

In one embodiment, a computer device is provided, which may be a server, and its internal structure diagram may be as shown in fig. 11. The computer device includes a processor, a memory, and a network interface connected by a system bus. Wherein the processor of the computer device is configured to provide computing and control capabilities. The memory of the computer device comprises a nonvolatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program, and a database. The internal memory provides an environment for the operation of an operating system and computer programs in the non-volatile storage medium. The network interface of the computer device is used for communicating with an external terminal through a network connection. The computer program is executed by a processor to implement a quantum communication method.

Those skilled in the art will appreciate that the architecture shown in fig. 11 is merely a block diagram of some of the structures associated with the disclosed aspects and is not intended to limit the computing devices to which the disclosed aspects apply, as particular computing devices may include more or less components than those shown, or may combine certain components, or have a different arrangement of components.

In one embodiment, a computer device is provided, comprising a memory and a processor, the memory having a computer program stored therein, the processor implementing the following steps when executing the computer program:

after the original information is pre-coded according to a quantum communication protocol, performing decorrelation processing on the pre-coded original information by using a random code word to obtain the pre-coded original information subjected to the decorrelation processing; modulating the quantum according to the pre-coded original information subjected to the decorrelation processing and the quantum communication protocol, and sending the modulated quantum to a second quantum communication end through a quantum channel; and obtaining the position of an effective code word in the pre-coded original information subjected to the disassociation processing and published after the modulated quantum is demodulated by the second quantum communication terminal, and publishing the random code word at the corresponding position and the disassociation processing mode according to the position of the effective code word in the pre-coded original information subjected to the disassociation processing.

In one embodiment, the processor, when executing the computer program, further performs the steps of: obtaining the code word length of the pre-coded original information; generating a string of random code words with the length not less than the code word length of the pre-coded original information; and carrying out exclusive or operation or exclusive or operation on each bit of the random code word and each bit of the pre-coded original information code word according to bits to obtain the pre-coded original information subjected to the decorrelation processing.

In one embodiment, the processor, when executing the computer program, further performs the steps of: obtaining a string of single photons which are polarized and randomly arranged; modulating the polarization state of the single photon according to the pre-coded original information subjected to the decorrelation processing and the quantum communication protocol; and sending the modulated single photons to a second quantum communication terminal through a quantum channel.

The implementation principle and technical effect of the computer device provided by the embodiment of the present application are similar to those of the method embodiment described above, and are not described herein again.

In one embodiment, a computer device is provided, comprising a memory and a processor, the memory having a computer program stored therein, the processor implementing the following steps when executing the computer program: receiving a modulated quantum sent by a first quantum communication terminal, demodulating the modulated quantum according to a quantum communication protocol, and obtaining pre-coded original information subjected to decorrelation processing; publishing the position of the effective code word in the pre-coded original information subjected to the disassociation processing; acquiring a random code word of a corresponding position published by a first quantum communication terminal and a disassociation processing mode; the published random code words at the corresponding positions and the disassociation processing mode are published by the first quantum communication terminal responding to the positions of the effective code words in the received pre-encoded original information published by the second quantum communication terminal and subjected to the disassociation processing; restoring effective information in the pre-coded original information subjected to the disassociation processing by using the random code words at the corresponding positions and the disassociation processing mode to obtain restored pre-coded effective information; and decoding the recovered pre-coded effective information by using the quantum communication protocol to obtain the effective information in the original information.

In one embodiment, the processor, when executing the computer program, further performs the steps of: randomly selecting a plurality of quanta which are successfully measured, and publishing the positions of the quanta which are successfully measured; obtaining public code words of the pre-coded original information which is published by the first quantum communication terminal and subjected to the decorrelation processing and corresponds to the positions of the quanta which are measured successfully; comparing whether the code words represented by the quantum with successful measurement are the same as the public code words published by the first quantum communication terminal to obtain a comparison result; calculating the bit error rate of the quantum channel according to the comparison result; and if the error rate exceeds a preset value, suspending communication.

In one embodiment, the processor, when executing the computer program, further performs the steps of: calculating the loss rate of the quantum channel according to the detection result; if the loss rate exceeds a preset value, the communication is suspended.

In an embodiment, a computer-readable storage medium is provided, on which a computer program is stored which, when being executed by a processor, carries out the steps of the above-mentioned method embodiments.

It will be understood by those skilled in the art that all or part of the processes of the methods of the embodiments described above can be implemented by hardware instructions of a computer program, which can be stored in a non-volatile computer-readable storage medium, and when executed, can include the processes of the embodiments of the methods described above. Any reference to memory, storage, database or other medium used in the embodiments provided herein can include at least one of non-volatile and volatile memory. Non-volatile Memory may include Read-Only Memory (ROM), magnetic tape, floppy disk, flash Memory, optical storage, or the like. Volatile Memory can include Random Access Memory (RAM) or external cache Memory. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM), among others.

The technical features of the above embodiments can be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the above embodiments are not described, but should be considered as the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims

1. A quantum communication method is applied to a first quantum communication end, and the method comprises the following steps:

after the original information is pre-coded according to a quantum communication protocol, performing decorrelation processing on the pre-coded original information by using a random code word to obtain the pre-coded original information subjected to the decorrelation processing;

modulating the quantum according to the pre-coded original information subjected to the disassociation processing and the quantum communication protocol, and sending the modulated quantum to a second quantum communication terminal through a quantum channel;

and obtaining the position of an effective code word in the pre-coded original information subjected to the disassociation processing and published after the modulated quantum is demodulated by the second quantum communication terminal, and publishing the random code word at the corresponding position and the disassociation processing mode according to the position of the effective code word in the pre-coded original information subjected to the disassociation processing.

2. The method of claim 1, wherein the performing the decorrelation processing on the pre-coded original information by using the random codeword to obtain the pre-coded original information subjected to the decorrelation processing comprises:

obtaining the code word length of the pre-coded original information;

generating a string of random code words with the length not less than the code word length of the pre-coded original information;

and carrying out exclusive OR operation or exclusive OR operation on each bit of the random code word and each bit of the pre-coded original information code word according to bits to obtain the pre-coded original information subjected to the disassociation processing.

3. The method of claim 1, wherein the modulating the quantum according to the pre-coded original information of the disassociation process and the quantum communication protocol, and the sending the modulated quantum to a second quantum communication end through a quantum channel comprises:

obtaining a string of single photons which are polarized and randomly arranged;

modulating the polarization state of the single photon according to the pre-coded original information subjected to the decorrelation processing and the quantum communication protocol;

and sending the modulated single photons to a second quantum communication terminal through the quantum channel.

4. A quantum communication method is applied to a second quantum communication terminal, and the method comprises the following steps:

receiving a modulated quantum sent by a first quantum communication terminal, and demodulating the modulated quantum according to a quantum communication protocol to obtain pre-coded original information subjected to decorrelation processing;

publishing the position of the effective code word in the pre-coded original information subjected to the disassociation processing;

acquiring a random code word of a corresponding position published by a first quantum communication terminal and a disassociation processing mode; the published random code words at the corresponding positions and the disassociation processing mode are published by the first quantum communication terminal responding to the positions of the effective code words in the received pre-encoded original information published by the second quantum communication terminal and subjected to the disassociation processing;

restoring effective information in the pre-coded original information subjected to the disassociation processing by using the random code words at the corresponding positions and the disassociation processing mode to obtain restored pre-coded effective information;

and decoding the recovered pre-coded effective information by using the quantum communication protocol to obtain the effective information in the original information.

5. The method of claim 4, further comprising:

randomly selecting a plurality of quanta which are successfully measured, and publishing the positions of the quanta which are successfully measured;

obtaining a public code word of the pre-coded original information which is published by the first quantum communication terminal and is subjected to the decorrelation processing and corresponds to the positions of the plurality of successfully-measured quanta, wherein the public code word is published by the first quantum communication terminal responding to the obtained positions of the plurality of successfully-measured quanta;

comparing whether the code words represented by the quantum with successful measurement are the same as the public code words to obtain a comparison result;

calculating the bit error rate of the quantum channel according to the comparison result;

and if the error rate exceeds a preset value, suspending communication.

6. The method of claim 4, further comprising:

calculating the loss rate of the quantum channel according to the detection result;

and if the loss rate exceeds a preset value, suspending communication.

7. A quantum communication device, for use at a first quantum communication end, the device comprising:

the decorrelation module is used for performing decorrelation processing on the pre-coded original information by using a random code word after pre-coding the original information according to a quantum communication protocol to obtain the pre-coded original information subjected to the decorrelation processing;

a modulation sending module, configured to modulate a quantum according to the precoded original information subjected to the decorrelation processing and the quantum communication protocol, and send the modulated quantum to a second quantum communication end through a quantum channel;

and the first publishing module is used for acquiring the position of an effective code word in the pre-coded original information subjected to the disassociation processing and published after the modulated quantum is demodulated by the second quantum communication terminal, and publishing the random code word at the corresponding position and the disassociation processing mode according to the position of the effective code word in the pre-coded original information subjected to the disassociation processing.

8. A quantum communication device, for use at a second quantum communication terminal, the device comprising:

a second publishing module, configured to publish a position of an effective codeword in the pre-coded original information subjected to the disassociation processing;

9. A computer device comprising a memory and a processor, the memory storing a computer program, characterized in that the processor, when executing the computer program, implements the steps of the method of any of claims 1 to 6.

10. A computer-readable storage medium, on which a computer program is stored, which, when being executed by a processor, carries out the steps of the method of any one of claims 1 to 6.