Base vector comparison interaction information transmission method based on pseudo-synchronous mask and Huffman coding

Abstract

The invention discloses a basis vector comparison interaction information transmission method based on pseudo-synchronous masks and Huffman codes, which is characterized in that the pseudo-synchronous masks are used for replacing synchronous serial numbers, and the Huffman codes are used for compressing synchronous information sent to an Alice end by a Bob end and detecting photon position coding information, so that the corresponding transmission bandwidth can be greatly reduced. Through sampling at the Bob end and directly sending the sampling information and the published key information to the Alice end, error rate statistics is completed by the Alice end, and light intensity information bandwidth occupation can be reduced. The Alice end replaces the corresponding detection photon position code by using the pseudo-synchronous mask after the basis vector comparison, so that the transmission bandwidth requirement from the Alice end to the Bob end can be reduced. In addition, the detection photon position coding bit width m and the Huffman coding table can be dynamically adjusted according to the detection rate so as to obtain the optimal performance; by means of the unique interactive code stream design, the base vector discarding recovery requirement can be met, and the encoding mode and the interactive code stream are allowed to be dynamically adjusted in real time so as to achieve the optimal performance.

Description

Technical Field

[0001] The present invention relates to the field of quantum technology, and more particularly to a method for transmitting interaction information of basis vector comparison based on pseudo-synchronous masking and Huffman coding. Background Art

[0002] With the continuous expansion of the quantum communication network, the gradual maturity of technologies and products, the quantum communication industry based on quantum key distribution (QKD) technology has entered the promotion period of product application, and quantum communication technology is being introduced into various industries to enhance system security. Quantum key distribution requires the QKD device to interactively send the sending basis vector of the sending end and the measurement basis vector of the receiving end, and the QKD devices at both ends screen out the keys with consistent basis vectors. The basis vector comparison negotiation interaction of QKD products is completed through the classical channel. In the popularization and application of QKD products, it is particularly sensitive to the classical network bandwidth occupied by the negotiation data.

[0003] When the QKD system performs basis vector comparison, the receiving party needs to synchronously transmit the detection position to the sending party. In order to save the communication bandwidth required to transmit this information, a suitable coding scheme should be adopted for the detection position. The existing schemes generally include the following:

[0004] One scheme is to adopt absolute position coding, which uses n bits to mark the absolute position of the detection position in all the transmitted signals during each basis vector comparison. n = Ceiling[log(2,N)] (Ceiling represents rounding up), and N is the total number of transmitted signals during each basis vector comparison. The total amount of transmitted information is nM, and M is the total number of detection positions of the receiving party among the N transmitted signals. In this scheme, the coding method is the simplest, but it directly transmits the original detection position, and the bandwidth occupied is very large. Calculated with a system with a light emission frequency of 1.25 GHz, for a QKD system with 100 KHz synchronous light, for each position, n = Ceiling[log(2,12500)] = 14 bits. If the number of detections per second is 2M, then at least 28 Mbps of transmission bandwidth is required. This is only the bandwidth occupied from the receiving end to the sending end. After the sending end completes the basis, the total two-way bandwidth is at least 42 Mbps.

[0005] Another solution is to use differential position encoding, which encodes the differential position (i.e., the absolute position difference between adjacent detection positions) using a variable-length encoding scheme and then sends it to the sender. Since the length of the differential position can be up to N - 1 at most, 0 at least, and the distribution of the differential position length is non-uniform, it is necessary to use a suitable variable-length encoding method to encode and compress the information of the differential position. However, it is very difficult to find an optimized encoding scheme. The existing differential position encoding adopts some simplified variable-length encoding schemes, encodes the differential position using multiple fixed-length encodings, and uses the reserved fixed-length information code to mark the length of the encoding. This simplified scheme is still relatively complex and troublesome to implement in engineering. Summary of the Invention

[0006] In view of the above-mentioned defects of the prior art, the present invention proposes a method for transmitting interaction information of basis vector comparison based on pseudo-synchronous mask and Huffman coding. Among them, the pseudo-synchronous mask is used to replace the synchronous sequence number, and the synchronous information and the detection photon position coding information sent from the Bob side to the Alice side are compressed by means of Huffman coding, which can greatly reduce the corresponding transmission bandwidth. At the same time, by sampling at the Bob side and directly sending the sampling information and the public key information to the Alice side for the Alice side to complete the error rate statistics, the occupancy of the corresponding optical intensity information bandwidth can be reduced. After the basis vector comparison, the Alice side uses the pseudo-synchronous mask to replace the corresponding detection photon position coding, which can reduce the transmission bandwidth requirement from the Alice side to the Bob side. In addition, the bit width m of the detection photon position coding and the Huffman coding table can be dynamically adjusted according to the detection rate to obtain the best performance; and with the help of a unique interactive code stream design, it can adapt to the requirement of basis vector discarding and recovery, and allows real-time dynamic adjustment of the coding method and the interactive code stream to achieve the optimal performance.

[0007] Specifically, the present invention discloses a method for transmitting interaction information of basis vector comparison based on pseudo-synchronous mask and Huffman coding, which includes a detection photon calculation step, a coding bit width calculation step, an information coding step, a compression coding step and an information transmission step; among them,

[0008] In the detection photon calculation step, according to the detection probability q of the QKD system, the number of detection photons n corresponding to the synchronous optical pulse is calculated;

[0009] In the coding bit width calculation step, according to the number of detection photons n, the bit width m for photon position coding and the number of bits F of the first pseudo-synchronous mask for the synchronous optical pulse are calculated, where, [.] is the rounding function, f sig is the emission frequency of the signal light, f sync is the synchronous optical frequency;

[0010] In the information coding step, with 2 mUsing a photon as the step value, the signal light corresponding to the synchronous optical pulse is divided into F photon intervals; setting the value of the i-th bit of the first pseudo-synchronous mask according to whether there is a detected photon in the i-th photon interval to generate the first pseudo-synchronous mask, where i = 1, …, F; and generating and recording the detection photon position encoding of the detected photon in the corresponding photon interval.

[0011] In the compression encoding step, perform Huffman encoding on the first pseudo-synchronous mask to generate the compressed first pseudo-synchronous mask.

[0012] In the information transmission step, transmit the compressed first pseudo-synchronous mask, the corresponding detection photon position encoding, and the basis vector information together.

[0013] Further, in the information encoding step, if there are multiple detected photons in a photon interval, randomly retain one detected photon and generate and record its detection photon position encoding in the corresponding photon interval.

[0014] Further, in the compression encoding step, generate a Huffman coding table according to the detection probability q, the dead time t dead and the position encoding bit width m, and perform Huffman encoding on the first pseudo-synchronous mask by querying the Huffman coding table.

[0015] Preferably, prepare multiple Huffman coding tables in advance according to different detection probabilities q.

[0016] Optionally, in the compression encoding step, use 4-bit Huffman encoding.

[0017] Further, the Bob side prepares sampling random numbers, and after transmitting the first pseudo-synchronous mask, the detection photon position encoding, and the basis vector information to the Alice side, also transmits the sampling information and the sampled and announced key information.

[0018] Further, after the Alice side completes the basis vector comparison, set the value of the i-th bit of the second pseudo-synchronous mask according to the failure or success of the basis comparison at the detection photon position in the i-th photon interval, generate the second pseudo-synchronous mask, and return the second pseudo-synchronous mask to the Bob side.

[0019] Preferably, before the Alice side returns the second pseudo-synchronous mask to the Bob side, also perform Huffman encoding on the second pseudo-synchronous mask to generate the compressed second pseudo-synchronous mask.

[0020] Further, the interactive code stream from the Bob side to the Alice side includes a first synchronization sequence number, an encoding method, position encoding information, and a code stream. The code stream includes a first pseudo-synchronization mask, a detected photon position encoding, basis vector information, sampling information, and sampled and announced key information. The encoding method is at least used to indicate the Huffman coding table for the first pseudo-synchronization mask, and the position encoding information is used to indicate the bit width for the detected photon position encoding.

[0021] Further, the interactive code stream from the Alice side to the Bob side includes a first synchronization sequence number, an encoding method, position encoding information, and a code stream. The code stream includes a second pseudo-synchronization mask. The encoding method is at least used to indicate the Huffman coding table for the second pseudo-synchronization mask, and the position encoding information is used to indicate the bit width for the detected photon position encoding. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Schematically shows an example of the first pseudo-synchronization mask encoding in the basis vector comparison interactive information transmission method for the present invention;

[0023] Figure 2 Schematically shows an example of the second pseudo-synchronization mask encoding used by the Alice side to replace the detected photon position encoding in the basis vector comparison interactive information transmission method of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0024] Hereinafter, the exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. The following embodiments are provided by way of example to fully convey the spirit of the present invention to those skilled in the art to which the present invention pertains. Therefore, the present invention is not limited to the embodiments disclosed herein.

[0025] The present invention proposes a basis vector comparison interactive information transmission method that can effectively reduce the classical communication bandwidth requirements. Based on the basis vector comparison implementation scheme, by means of a pseudo-synchronization mask and Huffman coding, the encoding bit width is dynamically adjusted according to the system detection rate, the detected photons are grouped, and the corresponding group numbers and the relative positions of the photons in the corresponding groups are interacted, thereby reducing the network bandwidth occupied by the basis vector comparison negotiation interaction in the QKD system.

[0026] Specifically, in the present invention, to obtain an encoding bit width adapted to the system detection rate, first, through the detected photon calculation step, the number of photons n detected by the Bob side corresponding to the signal light can be estimated for each synchronization optical pulse in terms of time.

[0027] For this purpose, for example, according to the detection rate statistical information and the detector dead time parameter t dead the detection probability q of the current QKD system can be obtained, and the number of detected photons n for each synchronization optical pulse in terms of time can be estimated or calculated.

[0028] For example, in a QKD system where the emission frequency f of the signal light sig = 1.25 GHz and the frequency f of the synchronization light sync = 100 KHz, according to the detection probability q of the current QKD system, the number of photons n detected within 10 us corresponding to each synchronization light pulse is calculated to be n = 10.

[0029] Thus, in the encoding bit width calculation step, formula (1) can be used to calculate the position encoding bit width m for photons in the current QKD system according to the number of detected photons n:

[0030]

[0031] where Floor[] is the floor function and [.] is the rounding function, f sig is the emission frequency of the signal light, and f sync is the frequency of the synchronization light.

[0032] Meanwhile, formula (2) can be used to further calculate the number of bits F of the first pseudo-synchronization mask for the synchronization light pulse in the current QKD system:

[0033]

[0034] where Ceiling[] is the ceiling function.

[0035] For example, when f sig = 1.25 GHz, f sync = 100 KHz, and n = 10, the bit width m of the detected photon position encoding can be calculated to be m = 10 according to formulas (1) and (2), and the number of bits F of the first pseudo-synchronization mask for the synchronization light pulse is F = 13.

[0036] In the present invention, in order to facilitate using the pseudo-synchronization mask to replace the conventional synchronization sequence number for the synchronization light pulse, it is necessary to ensure that within each signal light range (hereinafter referred to as "photon interval") containing 2 m photons, the number of detected photons obtained at the Bob end does not exceed 1.

[0037] To this end, the present invention proposes that the number of detected photons corresponding to each photon interval containing 2 dead photons can be estimated according to the detector dead time parameter t m and when the estimated number of detected photons is greater than 1, by randomly discarding the detected photons, it is ensured that the number of detected photons within each photon interval does not exceed 1.

[0038] Specifically, if t dead * f sig ≥ 2 m, it can be determined that there is no more than 1 detected photon in each photon interval.

[0039] If t dead *f sig <2 m , it indicates that there may be more than 1 detected photon in each photon interval. At this time, the detected photons in this photon interval can be randomly discarded to ensure that the number of detected photons in this photon interval is 1.

[0040] On this basis, in the information encoding step, 2 m photons can be used as the step value to divide the signal light corresponding to the synchronous optical pulse into F photon intervals.

[0041] For example, when f sig =1.25GHz, f sync =100KHz, m = 10, F = 13, the signal light corresponding to each synchronous optical pulse contains 12,500 photons. According to 1 photon interval corresponding to every 1024 signal photons, the interval ranges of the first 12 photon intervals are all 1024, and the interval range of the last photon interval is 12,500 - 1024 * 12 = 212.

[0042] Therefore, according to the present invention, for each synchronous optical pulse, the value of the i-th bit of the first pseudo-synchronous mask can be set according to whether there is a detected photon in the i-th photon interval, thereby generating the first pseudo-synchronous mask, where i = 1,..., F.

[0043] Figure 1 Schematically shows an example of the first pseudo-synchronous mask of the present invention for synchronous optical pulses.

[0044] As Figure 1 shown, assume that the number of bits F of the first pseudo-synchronous mask for synchronous optical pulses is 13, which corresponds to 13 photon intervals of the corresponding signal light. Among them, detected photons only exist in the 1st, 3rd, 4th, 7th, 9th, and 12th photon intervals. Therefore, the 1st, 3rd, 4th, 7th, 9th, and 12th bits of the first pseudo-synchronous mask are assigned the value 1, and other bits are assigned the value 0. Thus, the first pseudo-synchronous mask 1011001010010 for this synchronous optical pulse is encoded. Vice versa.

[0045] Furthermore, the position encoding of the detected photons in each photon interval can be performed by using the m-bit detected photon position encoding.

[0046] It can be seen that when the Bob side wants to send the basis comparison information to the Alice side, in addition to the non-compressible basis information, for each synchronous optical pulse, only F bits of pseudo-synchronous mask and n*m bits of detected photon position encoding need to be transmitted, thus greatly reducing the bandwidth required for transmitting the basis comparison information.

[0047] For example, in a QKD system where the emission frequency f sig of the signal light is 1.25 GHz, the synchronous optical frequency f sync is 100 KHz, and the number of photons detected within 10 us for each synchronous optical pulse is n = 10, the original position encoding for each detected photon requires 14 bits, and a total of 14 * 10 = 140 bits are required to represent the detected photon position encoding. For each second of time, 17 bits are needed to represent the synchronous sequence number for each synchronous optical pulse. Therefore, for each synchronous optical pulse, 140 + 17 = 157 bits are needed to transmit the synchronous sequence number and the detected photon position information.

[0048] As described above, for the same QKD system, m = 10 and F = 13. At this time, for each synchronous optical pulse, only 13 + 10 * 10 = 113 bits are needed to transmit the synchronous sequence number and the detected photon position information.

[0049] Although the use of the pseudo-synchronous mask described above can greatly reduce the bandwidth, there are still unreasonable aspects. That is, regardless of the distance and the link attenuation, the pseudo-synchronous mask needs to be transmitted. Even if the m value can be adjusted according to different transmission distances to reduce the number of pseudo-synchronous masks, there is still a waste of the pseudo-synchronous mask.

[0050] The inventor found through data analysis that when the detection rate is lower, there are more 0 values in the first pseudo-synchronous mask, and there is a large compression space. Therefore, it is further proposed that the entire first pseudo-synchronous mask can be compressed by means of a compression coding step, such as using 4-bit Huffman coding.

[0051] In the present invention, according to different detection probabilities q, dead times t dead and the photon interval 2 corresponding to the pseudo-synchronous mask m and other data, a modeling analysis can be carried out to establish a Huffman coding table, so as to perform Huffman coding on the first pseudo-synchronous mask by looking up the table.

[0052] For example, for the average detection rate q of each optical pulse, the number of emissions c = 2 m corresponding to each pseudo-synchronous mask, and the size K of the number of emissions corresponding to each bit of the pseudo-synchronous mask minus the number within the dead time. Assuming independent synchronous distribution in each interval, the following modeling analysis can be obtained:

[0053] The probability that a certain pseudo-synchronous mask is 0 is (1 - q). c ;

[0054] The probability of two consecutive bits of pseudo-synchronous mask:

[0055] fsp 00 = (1 - q) 2c ;

[0056] fsp 01 = cq(1 - q) (c+K-1) ;

[0057] fsp 10 = 1 + (1 - q) m (1 - (1 - q) m ) - (1 + Kq - q)(1 - q) (K-1) ;

[0058] fsp 11 = (1 + Kq - q)(1 - q) (K-1) - (1 - q) m - mq(1 - q) (m+K-1) ;

[0059] Accordingly, the probability corresponding to four consecutive bits of pseudo-synchronous mask can be calculated.

[0060] The probabilities calculated from the pseudo-synchronous masks are sorted from largest to smallest and corresponding Huffman coding is performed. The obtained coding table is as follows:

[0061]

[0062]

[0063] In the present invention, the parameters m and F for information coding can be dynamically adjusted according to the detection rate of the QKD system to ensure that the number of pseudo-synchronous masks can reach the optimum. Accordingly, multiple Huffman coding tables can be prepared in advance corresponding to different detection probabilities q, so as to perform switching coding and decoding according to actual link requirements.

[0064] In the present invention, to further reduce the bandwidth in the information interaction process, the present invention also particularly adopts the method of sampling at the Bob side. Sampling random numbers are prepared at the Bob side, and after transmitting the first pseudo-synchronous mask and the corresponding detection photon position coding and basis vector information (1 bit) to the Alice side, sampling information (1 bit) and sampled and announced key information (1 bit) are also sent.

[0065] After the Alice end receives data such as the first pseudo-synchronization mask, the detection photon position encoding, the basis vector information, the sampling information, and the sampled and announced key information, etc., it can complete the basis through the recovery of the synchronization sequence number and the detection photon position. At this time, the Alice end can also be allowed to complete the detection rate and error rate statistics, thereby saving the optical intensity information sent from the Alice end to the Bob end and reducing the bandwidth occupancy of the optical intensity information (2 bits).

[0066] After the Alice end completes the basis, it also needs to inform the Bob end of the detection photon position information of the successful basis. To further reduce the bandwidth required for information transmission, the present invention proposes that after the Alice end completes the basis vector comparison, it can set the value of the i-th bit of the second pseudo-synchronization mask according to the failure or success of the basis at the detection photon position in the i-th photon interval, generate the second pseudo-synchronization mask, and replace the original detection photon position encoding, so as to compress the information transmitted from the Alice end to the Bob end to only need to transmit the second pseudo-synchronization mask.

[0067] Figure 2 Schematically shows an example of the second pseudo-synchronization mask encoding used by the Alice end to replace the detection photon position encoding, which corresponds to Figure 1 the example of

[0068] As Figure 2 shown, by performing basis on the detection photon positions in the 1st, 3rd, 4th, 7th, 9th, and 12th photon intervals where there are detection photons, it is determined that the basis is successful in the 3rd, 4th, and 12th photon intervals. Therefore, the 3rd, 4th, and 12th bits of the second pseudo-synchronization mask are assigned the value 1, and the other bits are assigned the value 0. From this, the corresponding second pseudo-synchronization mask is encoded as 0011000000010.

[0069] Furthermore, when the Alice end returns the second pseudo-synchronization mask to the Bob end, similarly, for example, 4-bit Huffman coding can be used to compress the entire second pseudo-synchronization mask, thereby reducing the bandwidth required for information transmission.

[0070] In the present invention, the information transmission between the Alice end and the Bob end can also be implemented in a unique interactive code stream manner, thereby allowing classical network data to be discarded and recovered, and adapting to authentication processing schemes that support, for example, two-way basis vector comparison interactive data discarding.

[0071] According to the present invention, the interactive code stream for information transmission from the Bob end to the Alice end can include a first synchronization sequence number, an encoding method, position encoding information, and a code stream.

[0072] Among them, according to the information content transmitted from the Bob side to the Alice side (as described above), the code stream may include the first pseudo-synchronization mask, the detection photon position encoding, the basis vector information, the sampling information, and the sampled and announced key information, etc.

[0073] The encoding method may at least include the content for indicating the Huffman coding table for the first pseudo-synchronization mask. For example, 4’d0 is used to indicate that Huffman coding is not adopted in the first pseudo-synchronization mask, and 4’d1 is used to indicate that the prefabricated Huffman coding table 1 is used for compression coding in the first pseudo-synchronization mask….

[0074] The position encoding information may include the content for indicating the bit width of the detection photon position encoding. For example, 4’dm is used to indicate that the bit width of the detection photon position encoding is m.

[0075] The first synchronization sequence number is used to identify the current code stream, so as to facilitate, for example, discard and recovery processing.

[0076] Table 1 shows an example of the interactive code stream for information transmission from the Bob side to the Alice side:

[0077]

[0078] Table 1

[0079] With the form of this interactive code stream, the encoding end (here the Bob side) determines the encoding method, and the decoding end (here the Alice side) determines the encoding method according to the interactive code stream.

[0080] Similarly, the interactive code stream for information transmission from the Alice side to the Bob side may include the first synchronization sequence number, the encoding method, the position encoding information, and the code stream. Among them, the difference from the above is that the content of the code stream is different, and the code stream here includes the second pseudo-synchronization mask.

[0081] Table 2 shows an example of the interactive code stream for information transmission from the Alice side to the Bob side:

[0082]

[0083]

[0084] Table 2

[0085] In summary, the present invention proposes a method for transmitting interaction information of basis vector comparison implemented based on pseudo-synchronous mask and Huffman coding. Among them, the synchronous light is subdivided into pseudo-synchronous information, and only 1 photon is retained in each pseudo-synchronous information. The pseudo-synchronous mask is Huffman-coded to compress the synchronous information and position coding information sent from the Bob end to the Alice end; sampling is performed at the Bob end, and the sampled bits and the publicly announced secret key are directly sent to the Alice end. The error rate of basis vector comparison is statistically calculated at the Alice end, saving the optical intensity information sent from the Alice end to the Bob end and reducing the bandwidth occupancy of the optical intensity information; the positions after basis vector comparison at the Alice end are re-ordered, and alternative transmission is performed through the pseudo-synchronous mask, so that only the pseudo-synchronous mask needs to be transmitted from the Alice end to the Bob end, and there is no need to transmit the position coding of the detection photons, which can further reduce the classical bandwidth requirement. In addition, the bit width m of the position coding of the detection photons in the present invention can be dynamically adjusted according to the detection rate, and multiple Huffman tables can also be pre-set in advance according to the estimated probability to achieve the optimal overall performance. To adapt to the discarding of classical network data, an interactive code stream is designed, and the encoding end determines the encoding method, and the decoding end determines the encoding method according to the interactive code stream, which can dynamically adjust the encoding method and the interactive code stream in real time to achieve the optimal performance.

[0086] Although the present invention has been described above with reference to specific embodiments in conjunction with the accompanying drawings, it is easy for those skilled in the art to recognize that the above embodiments are merely exemplary and are used to illustrate the principle of the present invention, and they will not limit the scope of the present invention. Those skilled in the art can make various combinations, modifications, and equivalent substitutions to the above embodiments without departing from the spirit and scope of the present invention.

Claims

1. A method for transmitting interactive information of basis vector comparison based on pseudo-synchronous mask and Huffman coding, which includes a detection photon calculation step, a coding bit width calculation step, an information coding step, a compression coding step, and an information transmission step; wherein, In the detection photon calculation step, according to the detection probability q of the QKD system, calculate the number of detection photons n corresponding to the synchronous optical pulse; In the coding bit width calculation step, according to the number of detected photons n, calculate the position coding bit width m for photons and the number of bits F of the first pseudo-synchronization mask for the synchronization optical pulse, where, [.] is the rounding function, f sig is the emission frequency of the signal light, f sync is the synchronization optical frequency; In the information encoding step, using 2 m photons as the step value, dividing the signal light corresponding to the synchronous optical pulse into F photon intervals; setting the value of the i-th bit of the first pseudo-synchronous mask according to whether there are detected photons in the i-th photon interval to generate the first pseudo-synchronous mask, where i = 1, …, F; and generating and recording the detection photon position encoding of the detected photons in the corresponding photon intervals. In the compression coding step, perform Huffman coding on the first pseudo-synchronous mask to generate the compressed first pseudo-synchronous mask; In the information transmission step, transmit the compressed first pseudo-synchronous mask, the corresponding detection photon position coding, and the basis vector information in combination.

2. The base vector comparison interaction information transmission method according to claim 1, wherein, In the information coding step, if there are multiple detection photons in a photon interval, randomly retain one detection photon and generate and record its detection photon position coding in the corresponding photon interval.

3. The basis vector comparison interaction information transmission method according to claim 1, wherein, In the compression encoding step, a Huffman encoding table is generated based on the detection probability q, the dead time t dead and the position encoding bit width m, and the first pseudo-synchronization mask is Huffman encoded by querying the Huffman encoding table.

4. The method for transmitting interaction information of basis vector comparison as claimed in claim 3, wherein, Prepare multiple Huffman coding tables in advance according to different detection probabilities q.

5. The method for transmitting interaction information of basis vector comparison as claimed in claim 1, wherein, In the compression coding step, use 4-bit Huffman coding.

6. The method for transmitting interaction information of basis vector comparison as claimed in claim 1, wherein, The Bob side prepares sampling random numbers, and after transmitting the first pseudo-synchronous mask, the detection photon position coding, and the basis vector information to the Alice side, also transmits the sampling information and the sampled and announced key information.

7. The base vector comparison interaction information transmission method according to claim 1, wherein, After the Alice side completes the basis vector comparison, set the value of the i-th bit of the second pseudo-synchronous mask according to the failure or success of the basis comparison at the detection photon position in the i-th photon interval, generate the second pseudo-synchronous mask, and return the second pseudo-synchronous mask to the Bob side.

8. The method for transmitting interaction information of basis vector comparison as claimed in claim 7, wherein, Before the Alice side returns the second pseudo-synchronous mask to the Bob side, also perform Huffman coding on the second pseudo-synchronous mask to generate the compressed second pseudo-synchronous mask.

9. The basis vector comparison interaction information transmission method according to claim 1, wherein, The interactive code stream from the Bob side to the Alice side includes a first synchronization sequence number, a coding method, position coding information, and a code stream. The code stream includes the first pseudo-synchronous mask, the detection photon position coding, the basis vector information, the sampling information, and the sampled and announced key information. The coding method is at least used to indicate the Huffman coding table for the first pseudo-synchronous mask, and the position coding information is used to indicate the bit width for the detection photon position coding.

10. The basis vector comparison interaction information transmission method according to claim 1, wherein, The interactive code stream from the Alice side to the Bob side includes a first synchronization sequence number, a coding method, position coding information, and a code stream. The code stream includes the second pseudo-synchronous mask. The coding method is at least used to indicate the Huffman coding table for the second pseudo-synchronous mask, and the position coding information is used to indicate the bit width for the detection photon position coding.

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