A synchronous encoding and decoding method, a transmitting end and a receiving end

Abstract

The present application discloses a synchronous coding method, a transmitting end and a receiving end. In the embodiment of the present disclosure, a decoder is arranged to determine a second initialization vector according to a preset synchronization margin. The synchronization margin is used to make the second codeword synchronization value less than or equal to the first codeword synchronization value, thereby ensuring that the codeword synchronization value of the decoder at the receiving end is a one-way search for the codeword synchronization value of the transmitting end, and providing technical support for realizing fast synchronization of the decoder at the receiving end; by updating the second codeword synchronization value, it is ensured that the synchronization value of the receiving end continuously tracks and synchronizes the synchronization value of the transmitting end, effectively solving the synchronization problem of the receiving end when the codeword is lost; further, a shared random number is introduced as an initialization vector to ensure the random selection of different check matrices, and ensure that the dynamic check matrix used for each transmission task is different, thereby improving the security performance of the system.

Description

Technical Field

[0001] The present application relates to but is not limited to wireless communication technology, and particularly to a synchronous coding method, a transmitting end, and a receiving end. Background Art

[0002] With the rise of new technologies such as space information networks, wireless communication systems are facing the dual challenges of communication quality and confidentiality. How to ensure reliable information transmission and security performance in new application scenarios has become an important and critical issue. For this problem, the wireless communication solution in related technologies is to study encryption and error correction separately, and design the encryptor and decryptor and channel encoder and decoder relatively independently. This communication system with encryption and error correction separation does not take into account the overall characteristics of the communication system, and there are certain transmission performance bottlenecks and information leakage risks.

[0003] The physical layer security transmission system based on dynamic random matrix proposed in the related literature is an effective system that takes into account both the reliability and security of information transmission; Figure 1 Schematic diagram of a physical layer security transmission system based on a dynamic random matrix in related technologies, such as Figure 1 As shown in the figure, the core feature of the system is to generate a synchronized pseudo-random sequence based on the symmetric key at both ends of the transmission and reception for the extended construction of the dynamic check matrix, and one transmitted codeword corresponds to one dynamic check matrix. According to the generated dynamic check matrix, the transmitting end fusion encoder encrypts and encodes the plaintext, and the receiving end fusion decoder decodes and decrypts the received codeword, thereby realizing the integration and unification of the encryption and decryption functions and error correction capabilities of the entire system.

[0004] The above-mentioned secure transmission system based on dynamic random matrix does not fully consider the synchronization problem of the receiving and sending ends in the actual communication scenario. The system directly assumes that the sending and receiving ends are completely synchronized, and both start the synchronous jump coding from the initial sequence number 0; the defect of this approach is that in the actual communication scenario, codeword loss may occur due to factors such as inconsistent power-on time of the sending and receiving ends and channel blocking, resulting in the pseudo-random sequences of the sending and receiving ends no longer being synchronized, and the decoder cannot build a matching dynamic check matrix for the received codeword, which leads to decoding failure and the entire system cannot work normally; in addition, under the condition that the basic check matrix and symmetric key are fixed, the dynamic check matrix used by the sending codewords with the same sequence number is the same during multiple communications, and the eavesdropper can restore the check matrix according to the existing matrix reconstruction algorithm, which brings certain security risks. In summary, how to solve the synchronization and security problems of the physical layer secure transmission system based on dynamic random matrix has become a problem to be solved. Summary of the invention

[0005] The following is a summary of the subject matter described in detail in this application. This summary is not intended to limit the scope of the claims.

[0006] The embodiments of the present disclosure provide a synchronous coding method, a transmitting end and a receiving end, which can realize fast synchronization of a decoder at a receiving end.

[0007] The embodiment of the present disclosure provides a synchronous encoding and decoding method, which is applicable to the transmission of dynamic random matrices, including:

[0008] The transmitting end determines the first code word synchronization value according to the preset first initialization vector and the sending code word sequence number;

[0009] The transmitting end generates a first pseudo-random vector according to the determined first code word synchronization value and a predetermined symmetric key to construct a first dynamic check matrix;

[0010] The transmitting end encodes the message to be sent according to the constructed first dynamic check matrix, and sends the encoded message to the receiving end, where the encoded message includes n sending codewords, where n is a positive integer;

[0011] The receiving end determines a second codeword synchronization value of the i-th received codeword according to the second initialization vector, wherein the second initialization vector includes a preset synchronization margin, the synchronization margin is used to make the second codeword synchronization value less than or equal to the first codeword synchronization value, and i is a positive integer less than or equal to n;

[0012] The receiving end generates a second pseudo-random vector according to the symmetric key and the second code word synchronization value to construct a second dynamic check matrix;

[0013] The receiving end decodes the i-th received codeword in the message from the sending end according to the second dynamic check matrix to obtain a received plaintext of the i-th received codeword and an intermediate hard decision decoding result in the decoding process, where i is a positive integer;

[0014] The receiving end updates the second code word synchronization value of the (i+1)th received code word according to the intermediate hard decision decoding result and the second dynamic check matrix.

[0015] On the other hand, the embodiment of the present disclosure further provides a synchronous coding method, which is applicable to transmission oriented to a dynamic random matrix, including:

[0016] The transmitting end determines the first code word synchronization value according to the preset first initialization vector and the sending code word sequence number;

[0017] Generate a first pseudo-random vector according to the determined first codeword synchronization value and a predetermined symmetric key to construct a first dynamic check matrix;

[0018] Encode the message to be sent according to the constructed first dynamic check matrix, and send the encoded message to the receiving end, wherein the encoded message includes n sending codewords, where n is a positive integer;

[0019] Among them, the second codeword synchronization value of the i-th received codeword at the receiving end during synchronous encoding is determined according to the second initialization vector, i is a positive integer less than or equal to n, and the second initialization vector includes a pre-set synchronization margin, which is used to make the second codeword synchronization value less than or equal to the first codeword synchronization value.

[0020] On the other hand, the embodiment of the present disclosure further provides a synchronous coding method applicable to transmission oriented to a dynamic random matrix, including:

[0021] The receiving end determines a second codeword synchronization value of an i-th received codeword according to a second initialization vector, wherein the second initialization vector includes a preset synchronization margin, and the synchronization margin is used to make the second codeword synchronization value less than or equal to the first codeword synchronization value, and the i-th received codeword is the i-th codeword received by the receiving end;

[0022] Generate a second pseudo-random vector according to the symmetric key and the second code word synchronization value to construct a second dynamic check matrix;

[0023] Decoding the i-th received codeword in the message from the transmitting end according to the second dynamic check matrix to obtain a received plaintext of the i-th received codeword and an intermediate hard decision decoding result in the decoding process;

[0024] updating the second code word synchronization value of the i+1th received code word according to the intermediate hard decision decoding result and the second dynamic check matrix;

[0025] The first codeword synchronization value of the transmitting end of the synchronous coding is determined by the first initialization vector and the sending codeword sequence number.

[0026] In yet another aspect, an embodiment of the present disclosure further provides a computer storage medium, wherein a computer program is stored in the computer storage medium, and when the computer program is executed by a processor, the above-mentioned synchronous encoding and decoding method is implemented.

[0027] In another aspect, an embodiment of the present disclosure further provides a terminal, comprising: a memory and a processor, wherein the memory stores a computer program; wherein:

[0028] The processor is configured to execute the computer program in the memory;

[0029] When the computer program is executed by the processor, the synchronous encoding and decoding method as described above is implemented.

[0030] On the other hand, the embodiment of the present disclosure also provides a transmitting end of a synchronous coding code, which is suitable for transmission oriented to a dynamic random matrix, including: a first code word synchronization unit, a first pseudo-random vector generator, and a low-density parity check code LDPC encoder; wherein,

[0031] The first codeword synchronization unit is configured to: determine a first codeword synchronization value according to a preset first initialization vector and a transmitted codeword sequence number;

[0032] The first pseudo-random vector generator is configured to generate a first pseudo-random vector according to a determined first code word synchronization value and a predetermined symmetric key to construct a first dynamic check matrix;

[0033] The LDPC encoder is set to: encode the transmitted message according to the constructed first dynamic check matrix, and send the encoded message to the receiving end, wherein the encoded message includes n transmitted codewords, where n is a positive integer;

[0034] Among them, the second codeword synchronization value of the i-th received codeword at the receiving end during synchronous encoding is determined according to the second initialization vector, i is a positive integer less than or equal to n, and the second initialization vector includes a pre-set synchronization margin, which is used to make the second codeword synchronization value less than or equal to the first codeword synchronization value.

[0035] On the other hand, the embodiment of the present disclosure also provides a receiving end of a synchronous coding code, which is suitable for transmission oriented to a dynamic random matrix, including: a second code word synchronization unit, a second pseudo-random vector generator, and a low-density parity check code LDPC decoder; wherein,

[0036] The second codeword synchronization unit is configured to: determine a second codeword synchronization value of an i-th received codeword according to a second initialization vector, wherein the second initialization vector includes a preset synchronization margin, and the synchronization margin is used to make the second codeword synchronization value less than or equal to the first codeword synchronization value, and the i-th received codeword is the i-th codeword received by the receiving end;

[0037] The second pseudo-random vector generator is configured to generate a second pseudo-random vector according to the symmetric key and the second code word synchronization value to construct a second dynamic check matrix;

[0038] The LDPC decoder is configured to: decode the i-th received codeword in the message from the transmitter according to the second dynamic check matrix to obtain the received plaintext of the i-th received codeword and the intermediate hard decision decoding result in the decoding process; update the second codeword synchronization value of the i+1-th received codeword according to the intermediate hard decision decoding result and the second dynamic check matrix;

[0039] The first codeword synchronization value of the transmitting end of the synchronous coding is determined by the first initialization vector and the sending codeword sequence number.

[0040] In the disclosed embodiment, a decoder is arranged to determine a second initialization vector according to a preset synchronization margin, and the synchronization margin is used to make the second codeword synchronization value less than or equal to the first codeword synchronization value, thereby ensuring that the codeword synchronization value of the decoder at the receiving end is a one-way search for the codeword synchronization value of the transmitting end, and providing technical support for realizing fast synchronization of the decoder at the receiving end; by updating the second codeword synchronization value, it is ensured that the synchronization value of the receiving end continuously tracks and synchronizes the synchronization value of the transmitting end, and effectively solves the synchronization problem of the receiving end when the codeword is lost; further, a shared random number is introduced as an initialization vector to ensure the random selection of different check matrices, and to ensure that the dynamic check matrix used for each transmission task is different, thereby improving the security performance of the system.

[0041] Other features and advantages of the present application will be described in the following description, and partly become apparent from the description, or be understood by implementing the present application. Other advantages of the present application can be realized and obtained by the schemes described in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The accompanying drawings are used to provide an understanding of the technical solution of the present application and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the technical solution of the present application and do not constitute a limitation on the technical solution of the present application.

[0043] Figure 1 A schematic diagram of a physical layer security transmission system based on a dynamic random matrix is ​​provided for related technologies;

[0044] Figure 2 This is a flowchart of a synchronous encoding and decoding method according to a first embodiment of the present disclosure;

[0045] Figure 3 A flowchart of another synchronous encoding and decoding method according to an embodiment of the present disclosure;

[0046] Figure 4 A flowchart of another synchronous encoding and decoding method according to an embodiment of the present disclosure;

[0047] Figure 5 Schematic diagram of the structure of the transmitting end according to the embodiment of the present disclosure;

[0048] Figure 6 Schematic diagram of the structure of the receiving end of the embodiment of the present disclosure;

[0049] Figure 7 A schematic diagram of a basic check matrix according to an embodiment of the present disclosure;

[0050] Figure 8 Schematic diagram of the synchronization process in an embodiment of the present disclosure. DETAILED DESCRIPTION

[0051] The present application describes multiple embodiments, but the description is exemplary rather than restrictive, and it is obvious to those skilled in the art that there may be more embodiments and implementations within the scope of the embodiments described in the present application. Although many possible feature combinations are shown in the drawings and discussed in the specific embodiments, many other combinations of the disclosed features are also possible. Unless specifically limited, any feature or element of any embodiment may be used in combination with any other feature or element in any other embodiment, or may replace any other feature or element in any other embodiment.

[0052] The present application includes and contemplates combinations of features and elements known to those of ordinary skill in the art. The embodiments, features and elements disclosed in the present application may also be combined with any conventional features or elements to form a unique invention scheme defined by the claims. Any features or elements of any embodiment may also be combined with features or elements from other invention schemes to form another unique invention scheme defined by the claims. Therefore, it should be understood that any feature shown and / or discussed in the present application may be implemented individually or in any appropriate combination. Therefore, except for the limitations made according to the attached claims and their equivalents, the embodiments are not subject to other restrictions. In addition, various modifications and changes may be made within the scope of protection of the attached claims.

[0053] In addition, when describing representative embodiments, the specification may have presented the method and / or process as a specific sequence of steps. However, to the extent that the method or process does not rely on the specific order of the steps described herein, the method or process should not be limited to the steps of the specific order described. As will be understood by those of ordinary skill in the art, other sequences of steps are also possible. Therefore, the specific sequence of the steps set forth in the specification should not be interpreted as a limitation to the claims. In addition, the claims for the method and / or process should not be limited to the steps of performing them in the order written, and those skilled in the art can easily understand that these sequences can be changed and still remain within the spirit and scope of the embodiments of the present application.

[0054] Figure 2 This is a flowchart of a synchronous encoding and decoding method according to an embodiment of the present disclosure, which is applicable to transmission of dynamic random matrices, such as Figure 2 As shown, including:

[0055] Step 201: The transmitting end determines a first code word synchronization value according to a preset first initialization vector and a sending code word sequence number;

[0056] Step 202: The transmitting end generates a first pseudo-random vector according to the determined first code word synchronization value and a predetermined symmetric key to construct a first dynamic check matrix;

[0057] Step 203: The transmitting end encodes the message to be sent according to the constructed first dynamic check matrix, and sends the encoded message to the receiving end, where the encoded message includes n sending codewords, where n is a positive integer;

[0058] Step 204: The receiving end determines a second codeword synchronization value of the i-th received codeword according to the second initialization vector, wherein the second initialization vector includes a preset synchronization margin, and the synchronization margin is used to make the second codeword synchronization value less than or equal to the first codeword synchronization value, and i is a positive integer less than or equal to n;

[0059] Step 205: The receiving end generates a second pseudo-random vector according to the symmetric key and the second code word synchronization value to construct a second dynamic check matrix;

[0060] Step 206: The receiving end decodes the i-th received codeword in the message from the sending end according to the second dynamic check matrix to obtain the received plaintext of the i-th received codeword and the intermediate hard decision decoding result in the decoding process, where i is a positive integer.

[0061] Step 207: The receiving end updates the second code word synchronization value of the (i+1)th received code word according to the intermediate hard decision decoding result and the second dynamic check matrix.

[0062] In the disclosed embodiment, a decoder is arranged to determine a second initialization vector according to a preset synchronization margin, and the synchronization margin is used to make the second codeword synchronization value less than or equal to the first codeword synchronization value, thereby ensuring that the codeword synchronization value of the decoder at the receiving end is a one-way search for the codeword synchronization value of the transmitting end, and providing technical support for realizing fast synchronization of the decoder at the receiving end; by updating the second codeword synchronization value, it is ensured that the synchronization value of the receiving end continuously tracks and synchronizes the synchronization value of the transmitting end, and effectively solves the synchronization problem of the receiving end when the codeword is lost; further, a shared random number is introduced as an initialization vector to ensure the random selection of different check matrices, and to ensure that the dynamic check matrix used for each transmission task is different, thereby improving the security performance of the system.

[0063] The transmitted codeword in the embodiments of the present disclosure refers to the codeword transmitted by the transmitting end; the received codeword refers to the codeword received by the receiving end. Since the codeword may be lost during the transmission process, the transmitted codeword and the received codeword may not correspond.

[0064] Figure 3 This is a flowchart of another synchronous encoding and decoding method according to an embodiment of the present disclosure, which is applicable to the transmission of dynamic random matrices, such as Figure 3 As shown, including:

[0065] Step 301: The transmitting end determines a first code word synchronization value according to a preset first initialization vector and a sending code word sequence number;

[0066] Step 302: Generate a first pseudo-random vector according to the determined first code word synchronization value and a predetermined symmetric key to construct a first dynamic check matrix;

[0067] Step 303: Encode the message to be sent according to the constructed first dynamic check matrix, and send the encoded message to the receiving end, where the encoded message includes n sending codewords, where n is a positive integer;

[0068] Among them, the second codeword synchronization value of the i-th received codeword at the receiving end during synchronous encoding is determined according to the second initialization vector, i is a positive integer less than or equal to n, and the second initialization vector includes a pre-set synchronization margin, which is used to make the second codeword synchronization value less than or equal to the first codeword synchronization value.

[0069] In the disclosed embodiment, a decoder is arranged to determine a second initialization vector according to a preset synchronization margin. The synchronization margin is used to make the second codeword synchronization value less than or equal to the first codeword synchronization value, thereby ensuring that the codeword synchronization value of the decoder at the receiving end is a one-way search for the codeword synchronization value of the transmitting end, and providing technical support for realizing fast synchronization of the decoder at the receiving end; by updating the second codeword synchronization value, continuous tracking and synchronization of the synchronization value of the transmitting end by the synchronization value of the receiving end is ensured, effectively solving the synchronization problem of the receiving end when the codeword is lost; further, a shared random number is introduced as an initialization vector to ensure the random selection of different check matrices, to ensure that the dynamic check matrix used for each transmission task is different, and to improve the security performance of the system.

[0070] In an exemplary embodiment, the embodiment of the present disclosure determines a first codeword synchronization value, including:

[0071] The first initialization vector is summed with the transmitted codeword sequence number to obtain a first codeword synchronization value.

[0072] In an exemplary embodiment, the first initialization vector and the second initialization vector of the embodiment of the present disclosure can be set to a shared random number that can be shared by both the sender and the receiver. In an exemplary embodiment, the embodiment of the present disclosure can publicly send the same random number to the sender and the receiver through a trusted third party, such as a base station or a satellite, as the above-mentioned shared random number.

[0073] In an exemplary embodiment, the present disclosure:

[0074] The first initialization vector is the encoder power-on time;

[0075] The second initialization vector is the difference between the decoder startup time and the synchronization margin.

[0076] In an exemplary embodiment, the synchronization margin of the embodiment of the present disclosure may be set and adjusted by those skilled in the art based on experience. For example, it may be a time value within 1 to 20 hours, and the embodiment of the present disclosure is not limited to this.

[0077] The disclosed embodiment introduces the power-on time as the initialization vector to ensure that the dynamic check matrix used for each transmission task is different, thereby improving the security performance of the system.

[0078] Figure 4 This is a flowchart of another synchronous encoding and decoding method according to an embodiment of the present disclosure, which is applicable to the transmission of dynamic random matrices, such as Figure 4 As shown, including:

[0079] Step 401: The receiving end determines a second codeword synchronization value of an i-th received codeword according to a second initialization vector, wherein the second initialization vector includes a preset synchronization margin, and the synchronization margin is used to make the second codeword synchronization value less than or equal to the first codeword synchronization value, and the i-th received codeword is the i-th codeword received by the receiving end;

[0080] Step 402: Generate a second pseudo-random vector according to the symmetric key and the second code word synchronization value to construct a second dynamic check matrix;

[0081] Step 403: Decode the i-th received codeword in the message from the sender according to the second dynamic check matrix to obtain the y-th received codeword. i The received plaintext of the received codeword and the intermediate hard decision decoding results during the decoding process;

[0082] Step 404: Update the second code word synchronization value of the (i+1)th received code word according to the intermediate hard decision decoding result and the second dynamic check matrix;

[0083] The first codeword synchronization value of the transmitting end of the synchronous coding is determined by the first initialization vector and the sending codeword sequence number.

[0084] In the disclosed embodiment, a decoder is arranged to determine a second initialization vector according to a preset synchronization margin. The synchronization margin is used to make the second codeword synchronization value less than or equal to the first codeword synchronization value, thereby ensuring that the codeword synchronization value of the decoder at the receiving end is a one-way search for the codeword synchronization value of the transmitting end, and providing technical support for realizing fast synchronization of the decoder at the receiving end; by updating the second codeword synchronization value, continuous tracking and synchronization of the synchronization value of the transmitting end by the synchronization value of the receiving end is ensured, effectively solving the synchronization problem of the receiving end when the codeword is lost; further, a shared random number is introduced as an initialization vector to ensure the random selection of different check matrices, to ensure that the dynamic check matrix used for each transmission task is different, and to improve the security performance of the system.

[0085] In an exemplary embodiment, the embodiment of the present disclosure updates the second codeword synchronization value of the (i+1)th received codeword, including:

[0086] The receiving end determines the number of check equations that do not satisfy the check relationship according to the intermediate hard decision decoding result of the i-th received codeword and the second dynamic check matrix;

[0087] The receiving end determines whether the current second dynamic check matrix matches the received codeword by determining the number of check equations that do not satisfy the check relationship;

[0088] The receiving end updates the second code word synchronization values ​​of i+1 received code words according to whether the current second dynamic check matrix matches the received code word.

[0089] In an exemplary embodiment, the embodiment of the present disclosure determines whether the current second dynamic check matrix matches the received codeword, including:

[0090] When the number of check equations that do not satisfy the check relationship is less than a preset error threshold, determining that the second dynamic check matrix matches the received codeword;

[0091] When the number of check equations that do not satisfy the check relationship is greater than or equal to the error threshold, it is determined that the second dynamic check matrix fails to match the received codeword.

[0092] In an exemplary embodiment, the embodiment of the present disclosure updates the second codeword synchronization value of the (i+1)th received codeword, including:

[0093] The receiving end determines that the current second dynamic check matrix matches the received codeword, determines that the codeword synchronization is successful, and updates

[0094] The receiving end determines that the current second dynamic check matrix fails to match the received codeword, determines that the codeword synchronization fails, and updates

[0095] in, The upper right subscript in the middle indicates the received codeword sequence number. represents the second codeword synchronization value of the i-th received codeword.

[0096] In an exemplary embodiment, the first initialization vector and the second initialization vector of the embodiment of the present disclosure include: a shared random number determined in a pre-determined manner.

[0097] In an exemplary embodiment, in the embodiment of the present disclosure, the first initialization vector is the power-on time of the encoder; and the second initialization vector is the difference between the power-on time of the decoder and the synchronization margin.

[0098] In an exemplary embodiment, the second codeword synchronization value of the first received codeword in the embodiment of the present disclosure is

[0099] in, The upper right subscript in the middle indicates the received codeword sequence number. Indicates the second codeword synchronization value of the first received codeword, IV dec Represents the second initialization vector.

[0100] The embodiment of the present disclosure further provides a computer storage medium, in which a computer program is stored. When the computer program is executed by a processor, the above-mentioned synchronous encoding and decoding method is implemented.

[0101] The embodiment of the present disclosure also provides a terminal, including: a memory and a processor, wherein a computer program is stored in the memory;

[0102] in,

[0103] The processor is configured to execute the computer program in the memory;

[0104] When the computer program is executed by a processor, the synchronous encoding and decoding method as described above is implemented.

[0105] The embodiment of the present disclosure also provides a synchronous coding and decoding transmitting end, which is suitable for dynamic random matrix oriented transmission, including: a first code word synchronization unit, a first pseudo-random vector generator, and a low-density parity check code LDPC encoder; wherein,

[0106] The first codeword synchronization unit is configured to: determine a first codeword synchronization value according to a preset first initialization vector and a transmitted codeword sequence number;

[0107] The first pseudo-random vector generator is configured to generate a first pseudo-random vector according to a determined first code word synchronization value and a predetermined symmetric key to construct a first dynamic check matrix;

[0108] The LDPC encoder is set to: encode the transmitted message according to the constructed first dynamic check matrix, and send the encoded message to the receiving end, wherein the encoded message includes n transmitted codewords, where n is a positive integer;

[0109] Among them, the second codeword synchronization value of the i-th received codeword at the receiving end during synchronous encoding is determined according to the second initialization vector, i is a positive integer less than or equal to n, and the second initialization vector includes a pre-set synchronization margin, which is used to make the second codeword synchronization value less than or equal to the first codeword synchronization value.

[0110] In the disclosed embodiment, a decoder is arranged to determine a second initialization vector according to a preset synchronization margin. The synchronization margin is used to make the second codeword synchronization value less than or equal to the first codeword synchronization value, thereby ensuring that the codeword synchronization value of the decoder at the receiving end is a one-way search for the codeword synchronization value of the transmitting end, and providing technical support for realizing fast synchronization of the decoder at the receiving end; by updating the second codeword synchronization value, continuous tracking and synchronization of the synchronization value of the transmitting end by the synchronization value of the receiving end is ensured, effectively solving the synchronization problem of the receiving end when the codeword is lost; further, a shared random number is introduced as an initialization vector to ensure the random selection of different check matrices, to ensure that the dynamic check matrix used for each transmission task is different, and to improve the security performance of the system.

[0111] In an exemplary embodiment, the first codeword synchronization unit of the embodiment of the present disclosure is configured as:

[0112] The first initialization vector is summed with the transmitted codeword sequence number to obtain a first codeword synchronization value.

[0113] In an exemplary embodiment, the first initialization vector and the second initialization vector of the embodiment of the present disclosure include: a shared random number determined in a pre-determined manner.

[0114] In an exemplary embodiment, the present disclosure:

[0115] The first initialization vector is the encoder power-on time;

[0116] The second initialization vector is the difference between the decoder startup time and the synchronization margin.

[0117] The embodiment of the present disclosure also provides a synchronous coding receiving end, which is suitable for dynamic random matrix oriented transmission, including: a second code word synchronization unit, a second pseudo-random vector generator, and an LDPC decoder; wherein,

[0118] The second codeword synchronization unit is configured to: determine a second codeword synchronization value of an i-th received codeword according to a second initialization vector, wherein the second initialization vector includes a preset synchronization margin, and the synchronization margin is used to make the second codeword synchronization value less than or equal to the first codeword synchronization value, and the i-th received codeword is the i-th codeword received by the receiving end;

[0119] The second pseudo-random vector generator is configured to generate a second pseudo-random vector according to the symmetric key and the second code word synchronization value to construct a second dynamic check matrix;

[0120] The LDPC decoder is configured to: decode the i-th received codeword in the message from the transmitter according to the second dynamic check matrix to obtain the received plaintext of the i-th received codeword and the intermediate hard decision decoding result in the decoding process; update the second codeword synchronization value of the i+1-th received codeword according to the intermediate hard decision decoding result and the second dynamic check matrix;

[0121] The first codeword synchronization value of the transmitting end of the synchronous coding is determined by the first initialization vector and the sending codeword sequence number.

[0122] In the disclosed embodiment, a decoder is arranged to determine a second initialization vector according to a preset synchronization margin, and the synchronization margin is used to make the second codeword synchronization value less than or equal to the first codeword synchronization value, thereby ensuring that the codeword synchronization value of the decoder at the receiving end is a one-way search for the codeword synchronization value of the transmitting end, and providing technical support for realizing fast synchronization of the decoder at the receiving end; by updating the second codeword synchronization value, it is ensured that the synchronization value of the receiving end continuously tracks and synchronizes the synchronization value of the transmitting end, and effectively solves the synchronization problem of the receiving end when the codeword is lost; further, a shared random number is introduced as an initialization vector to ensure the random selection of different check matrices, and to ensure that the dynamic check matrix used for each transmission task is different, thereby improving the security performance of the system.

[0123] In an exemplary embodiment, the LDPC decoder of the embodiment of the present disclosure is configured to update the second codeword synchronization value of the i+1th received codeword, including:

[0124] The receiving end determines the number of check equations that do not satisfy the check relationship according to the intermediate hard decision decoding result of the i-th received codeword and the second dynamic check matrix;

[0125] The receiving end determines whether the current second dynamic check matrix matches the received codeword by determining the number of check equations that do not satisfy the check relationship;

[0126] The receiving end updates the second code word synchronization values ​​of i+1 received code words according to whether the current second dynamic check matrix matches the received code word.

[0127] In an exemplary embodiment, the LDPC decoder of the embodiment of the present disclosure is configured to determine whether the current second dynamic check matrix matches the received codeword, including:

[0128] When the number of check equations that do not satisfy the check relationship is greater than or equal to a preset error threshold, determining that the second dynamic check matrix matches the received codeword;

[0129] When the number of check equations that do not satisfy the check relationship is less than an error threshold, it is determined that the second dynamic check matrix fails to match the received codeword.

[0130] In an exemplary embodiment, the LDPC decoder of the embodiment of the present disclosure is configured to update the second codeword synchronization value of the i+1th received codeword, including:

[0131] The receiving end determines that the current second dynamic check matrix matches the received codeword, determines that the codeword synchronization is successful, and updates

[0132] The receiving end determines that the current second dynamic check matrix fails to match the received codeword, determines that the codeword synchronization fails, and updates

[0133] in, The upper right subscript in the middle indicates the received codeword sequence number. represents the second codeword synchronization value of the i-th received codeword.

[0134] In an exemplary embodiment, the first initialization vector and the second initialization vector of the embodiment of the present disclosure include: a shared random number determined in a pre-determined manner.

[0135] In an exemplary embodiment, the first initialization vector in the embodiment of the present disclosure is the encoder power-on time, and the second initialization vector is the difference between the decoder power-on time and the synchronization margin.

[0136] In an exemplary embodiment, the second codeword synchronization value of the first received codeword in the embodiment of the present disclosure is

[0137] in, The upper right subscript in the middle indicates the received codeword sequence number. Indicates the second codeword synchronization value of the first received codeword, IV dec Represents the second initialization vector.

[0138] The following briefly describes the embodiments of the present disclosure through application examples. The application examples are only used to illustrate the embodiments of the present disclosure and are not used to limit the protection scope of the embodiments of the present disclosure.

[0139] Application Examples The disclosed embodiment proposes a method of synchronous encoding and decoding, which is suitable for transmission oriented to dynamic random matrices, solves the codeword synchronization problem of the original secure transmission, and can achieve correct synchronization and decoding of the receiving end decoder when the codeword is lost during the transmission process; by introducing the power-on time as the initialization vector, it is ensured that the dynamic check matrix used for each transmission task is different, thereby improving the security performance of the system.

[0140] Figure 5 Schematic diagram of the structure of the transmitting end according to the embodiment of the present disclosure. Figure 6 This is a schematic diagram of the structure of the receiving end of the embodiment of the present disclosure, see Figure 5 and Figure 6 The synchronous encoding and decoding method of the embodiment of the present disclosure includes:

[0141] On the sending end, set the encoder power-on time to the first initialization vector IV enc , the first code word synchronization value The first initialization vector IV encThe first pseudo-random vector generator refers to the relevant technology, according to the symmetric key and the first code word synchronization value Generate a first pseudo-random vector; construct a first dynamic check matrix by a first check matrix constructor; and encode the message by an LDPC encoder according to the first dynamic check matrix;

[0142] At the receiving end, the difference between the decoder startup time and the preset synchronization margin is set as the second initialization vector IV dec , ensure that the second code word synchronization value of the receiving end never exceeds the first code word synchronization value of the sending end; set the second code word synchronization value of the receiving end when receiving the first frame message The second initialization vector IV dec +1; when the second frame message is received, the second pseudo-random vector generator at the receiving end synchronizes the value of the second code word according to the symmetric key A second pseudo-random vector is generated, and a second dynamic check matrix is ​​constructed by a second check matrix constructor. The LDPC decoder decodes the received codeword according to the second dynamic check matrix to obtain the received plaintext, and obtains an intermediate hard decision decoding result in the decoding process; the number of check equations that do not satisfy the check relationship is calculated according to the intermediate hard decision decoding result and the second dynamic check matrix, and it is determined whether the current second dynamic check matrix matches the received codeword by comparing with the set error threshold, and a feedback signal is output; according to the feedback signal, the second codeword synchronization value of the next received codeword is updated according to a preset strategy.

[0143] The following is a definition of the symbols used in the synchronous encoding method of the embodiment of the present disclosure. Before the synchronous encoding begins, the sender and the receiver agree on a symmetric key k of length l bits through a key exchange protocol; the sender and the receiver agree on a symmetric key of length m bits. B ×n B The basic check matrix H B , and matrix expansion factor T; codeword length n = n B ·T, information bit length k = (n B -m B )·T, check bit length m=m B ·T, the size of the first dynamic check matrix at the transmitting end and the second dynamic check matrix at the receiving end are both m×n; the length of the pseudo-random vector used to construct the first dynamic check matrix and the second dynamic check matrix is ​​r=J·log2T, where J is the basic check matrix H B The number of elements "1" in the sender startup time is Time enc , the first initialization vector of the sender is IV enc , and send plaintext m to the i-th i , the first code word synchronization value is set to The first dynamic check matrix constructed is The generated transmission codeword is x i ; The receiving end startup time is Time dec , the second initialization vector at the receiving end is IV dec , and for the i-th received codeword y i The second code word synchronization value is set to The second dynamic check matrix constructed is The received plaintext is m′ i .

[0144] In the synchronous encoding and decoding method of the disclosed embodiment, the sending end generates a sending codeword for processing, including:

[0145] 1) Set the first initialization vector of the sender to IV enc The encoder startup time enc , that is, IV enc =Time enc ;

[0146] 2) The sender segments the message into k-bit segments and obtains the plaintext sequence (m1, m2, ..., m i ,…), serial number i=1,2,…;

[0147] 3) The first pseudo-random vector generator at the transmitting end generates a first code word synchronization value according to the symmetric key k and the first code word synchronization value. Generate a first pseudo-random vector, the first pseudo-random vector includes a first control pseudo-random vector with a length of r bits and the first encrypted pseudo-random vector of length k bits That is, the first pseudo-random vector

[0148] 4) The transmitter check matrix constructor controls the pseudo-random vector For the basic check matrix H B Expand and generate the i-th first dynamic check matrix Right now And further obtain the corresponding generator matrix; the first dynamic check matrix can be constructed by the following method: the first control pseudo-random vector Divide into J segments according to log2T bits, each segment corresponds to the basic check matrix H B A "1" element in the basic check matrix H B Each element in is expanded into a T×T circulant matrix, where element "0" is expanded into an all-zero matrix, element "1" is expanded into a circulant matrix with row weight 1, and the position of the first row 1 is controlled by the first pseudo-random vector The value of the corresponding segment determines;

[0149] 5) The first encrypted pseudo-random vector Send plaintext m i Perform bit-by-bit XOR operation to obtain the ciphertext v with a length of k bits i ; LDPC encoder according to the ciphertext v i and the first control pseudo-random vector The corresponding generator matrix generates the i-th transmitted codeword x i .

[0150] The decoding process at the receiving end includes:

[0151] 6) The transmission codeword sequence (x1, x2, ..., x i ,…) After being transmitted through the main channel, the receiving end obtains the received codeword sequence (y1,y2,…,y i ,…);

[0152] 7) Set the second initialization vector IV of the receiving end dec Time is the time when the decoder is turned on dec The difference between the set synchronization margin ΔTime, that is, the second initialization vector IV dec =Time dec -ΔTime, where ΔTime should make IV dec ≤ IV enc , that is, Time dec -ΔTime≤Time enc ;

[0153] 8) Set the second code word synchronization value of the first received code word y1 to

[0154] 9) For the i-th received codeword y i ,i=1,2,…, the receiving end uses the basic check matrix H B , symmetric key k, and second codeword synchronization value Through the existing LDPC iterative decoding algorithm, y i Perform channel decoding and output the intermediate hard decision decoding result g i and receive plaintext m′ i , which may include:

[0155] 9.1) Based on the symmetric key k and the second code word synchronization value The pseudo-random number generator generates a second pseudo-random vector by a symmetric encryption algorithm, and the second pseudo-random vector includes a second control pseudo-random vector with a length of r bits. and a second encrypted pseudo-random vector of length k bits Right now

[0156] 9.2) According to the basic check matrix H B and a second control pseudo-random vector Construct the second dynamic check matrix

[0157] 9.3) LDPC decoder according to the second dynamic check matrix For the received codeword y i Perform iterative decoding and set the total number of iterations to ITER total ; The decoding algorithm adopts the existing LDPC soft decision iterative algorithm, such as BP decoding algorithm, minimum sum decoding algorithm, etc.;

[0158] 9.4) At ITER check After iterations, the decoder obtains the n-bit intermediate hard decision decoding result g i , of which ITER check <ITER total ;ITER total After iterations, output k bits of received ciphertext v′ i ;

[0159] 9.5) Receive ciphertext v′ i with the second encrypted pseudo-random vector Perform bit-by-bit XOR operation to obtain the k-bit received plaintext m′ i ;

[0160] 10) According to the intermediate hard decision decoding result g generated in step 9) i and the second dynamic check matrix Calculate the number of calibration equations that do not satisfy the calibration relationship: Where is a 1×m all-1 vector;

[0161] 11) Set the error threshold Err_threshold, Err_threshold is an integer and 0≤Err_threshold≤m; if w i ≤Err_threshold, indicating that the second dynamic check matrix and the received codeword y i Match, synchronization is successful, let the feedback signal f i =1; otherwise the synchronization fails and the feedback signal f i =0;

[0162] 12) The feedback signal f generated according to step 11) i , update the next received codeword y i+1 The second code word synchronization value The specific method is: if f i =1, indicating that the previous codeword has been correctly synchronized and updated If fi =0, that is, the previous codeword synchronization failed, update

[0163] In the embodiment of the present disclosure, the transmitting end sends the PN23 pseudo-random sequence, and the basic check matrix H is used. B like Figure 7 As shown, the size is 64×96, that is, n B =64,m B =96; basic check matrix H B Each black square in represents a "1" element, the total number of which is J = 256, and the rest are "0" elements; the matrix expansion factor T = 32, and the length of the pseudo-random vector r used to construct the dynamic check matrix is ​​r = Jlog2T = 1280 bits; through the matrix expansion construction, a 2048×3072 dynamic check matrix H can be obtained, corresponding to a code rate of 1 / 3, a coding parameter of (3072,1024) LDPC code, a code length n = 3072, and an information bit length k = 1024. The national secret SM4 block cipher algorithm is used as the pseudo-random vector generation algorithm; the secure communication method based on dynamic matrix coding that can be efficiently synchronized in the disclosed embodiment includes:

[0164] (1) On the sending end, configure the encoder's IV enc The value is the encoder power-on time in minutes enc ;

[0165] (2) The sender divides the PN23 pseudo-random sequence generated by the data source into segments of k = 1024 bits to obtain the plaintext sequence (m1, m2, ..., m i ,…);

[0166] (3) According to the plaintext m i Generate n = 3072 bits to send codeword x i , the processing flow is:

[0167] (3.1) Setting the first codeword synchronization value According to the first code word synchronization value With the symmetric key k, the first pseudo-random vector generator generates a first pseudo-random vector, the first pseudo-random vector includes a first control pseudo-random vector of r=1280 bits and a first encrypted pseudo-random vector of k=1024 bits

[0168] (3.2) The check matrix constructor is based on the basic check matrix H B and the first control pseudo-random vector Construct the first dynamic check matrix of 2048×3072 The specific method is: the first control pseudo-random vector Divide into 5-bit segments, a total of 256 segments, each segment corresponds to the basic check matrix H B A "1" element in H B Each element in is expanded into a 32×32 circulant matrix, where the element "0" is expanded into an all-zero matrix, the element "1" is expanded into a circulant matrix with a row weight of 1, and the position of the first row 1 is The value of the corresponding segment determines;

[0169] (3.3) The first encrypted pseudo-random vector Send plaintext m i XOR each bit to get the ciphertext v of k=1024 bits i .

[0170] (3.4) According to the first dynamic check matrix The corresponding generator matrix is ​​obtained, and the LDPC encoder encodes the ciphertext v according to the obtained generator matrix i Encode and obtain n = 3072 bits of transmitted codeword x i ;

[0171] (4) Send the codeword sequence (x1, x2, …, x i ,…) is sent to the main channel for transmission;

[0172] (5) At the receiving end, the received codewords are recorded in order as (y1, y2, ..., y i ,…), each received codeword y i is a real number vector of dimension n=3072;

[0173] (6) At the receiving end, configure the decoder's IV dec Time, the decoder startup time in minutes dec The difference with the synchronization margin ΔTime, ΔTime is set to 20;

[0174] (7) At the receiving end, for each received codeword y i Perform joint error correction encryption decoding to obtain the corresponding k=1024-bit received plaintext m′ i ,include:

[0175] (7.1) The pseudo-random number generator is based on the symmetric key k and the second code word synchronization value Generate a second pseudo-random vector, the second pseudo-random vector includes a second control pseudo-random vector with a length of 1280 bits and a second encrypted pseudo-random vector of length 1024 bits

[0176] (7.2) The receiving end check matrix constructor controls the pseudo-random vector Construct the second dynamic check matrix of size 2048×3072

[0177] (7.3) The LDPC decoder receives the codeword y i LDPC decoding is performed in the ITER check = After 20 iterations, the intermediate iteration result g with a length of 3072 bits is obtained i , at the ITER total = After 60 iterations, the received ciphertext v′ with a length of 1024 bits is output i ;

[0178] (7.4) Receive the ciphertext v′ i and the second encrypted pseudo-random vector u i XOR bit by bit to get the received plaintext m′ i ;

[0179] (8) According to the intermediate iteration result g of the LDPC decoder i Performing real-time updating of the second code word synchronization value may include:

[0180] (8.1) Calculation And w i and error threshold Err threshold =700 comparison. If w i ≤700, let the feedback signal f i =1; if w i >700, let the feedback signal f i =0;

[0181] (8.2) According to the feedback signal f i The value of f determines the second code word synchronization value of the next received code word: i =1, let If f i =0, let

[0182] In order to illustrate that the synchronous coding method and system of the embodiment of the present disclosure have efficient synchronization capability, the probability of each codeword loss is set to 0.1. Figure 8The synchronization process of the first 50 codewords is shown; due to codeword loss, the receiving end only receives 45 codewords. Curve 8-1 in the figure represents the encoder synchronization value, and curve 8-2 represents the decoder synchronization value. The overlapping part of the two curves is the synchronization stage. It can be seen from the figure that due to the asynchronous startup time, the initial synchronization value of the decoder differs from the initial synchronization value of the encoder by 10; before the 12th codeword, the slope of the decoder's synchronization curve is twice that of the encoder's synchronization curve, so that a rapid search for the synchronization value can be completed and synchronization is completed at the 12th codeword. Afterwards, two consecutive codewords were lost at the 28th and 37th received codewords, but the decoder was able to resynchronize within three steps. Therefore, the synchronous encoding and decoding method proposed in this method can effectively solve the codeword synchronization problem of the dynamic random matrix security transmission system in actual communication scenarios.

[0183] In addition, when the system is used for communication multiple times, the constructed pseudo-random sequence and dynamic check matrix are different due to different power-on times, which prevents eavesdroppers from deciphering the check matrix based on the codewords sent with the same sequence number, effectively improving the security of the system.

[0184] The disclosed embodiment sets the initialization vector of the decoder to be the difference between the power-on time of the decoder and the synchronization margin, sets the codeword synchronization value of the encoder to be the sum of the power-on time of the encoder and the codeword sequence number, and the pseudo-random vector generator generates a pseudo-random vector according to the codeword synchronization value and the symmetric key, constructs a dynamic check matrix, and encodes the sent plaintext, which can ensure that the codeword synchronization value of the decoder at the receiving end is a one-way search for the codeword synchronization value of the sending end, and facilitates the rapid synchronization of the decoder at the receiving end. The design of the codeword synchronization value introduces time randomness, ensures the random selection of the check matrix when communicating at different times, and improves the security of the system. The decoder outputs the intermediate iteration result during the iteration process; compares the product result of the intermediate iteration result and the dynamic check matrix with the error threshold, determines whether the check matrix matches the codeword, and outputs a feedback signal; updates the codeword synchronization value of the next received codeword according to the feedback signal, ensures that the synchronization value of the receiving end continuously tracks and synchronizes the synchronization value of the sending end, and can effectively solve the synchronization problem of the receiving end when the codeword is lost.

[0185] It will be appreciated by those skilled in the art that all or some of the steps, systems, and functional modules / units in the methods disclosed above may be implemented as software, firmware, hardware, and appropriate combinations thereof. In hardware implementations, the division between the functional modules / units mentioned in the above description does not necessarily correspond to the division of physical components; for example, a physical component may have multiple functions, or a function or step may be performed by several physical components in cooperation. Some or all components may be implemented as software executed by a processor, such as a digital signal processor or a microprocessor, or implemented as hardware, or implemented as an integrated circuit, such as an application-specific integrated circuit. Such software may be distributed on a computer-readable medium, which may include a computer storage medium (or non-transitory medium) and a communication medium (or temporary medium). As known to those skilled in the art, the term computer storage medium includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information (such as computer-readable instructions, data structures, program modules, or other data). Computer storage media include, but are not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tapes, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store the desired information and can be accessed by a computer. In addition, it is well known to those of ordinary skill in the art that communication media typically contain computer-readable instructions, data structures, program modules, or other data in a modulated data signal such as a carrier wave or other transport mechanism, and may include any information delivery media.

Claims

1. A synchronous encoding and decoding method, suitable for transmission of dynamic random matrices, characterized in that: include: The transmitting end determines the first code word synchronization value according to the preset first initialization vector and the sending code word sequence number; The transmitting end generates a first pseudo-random vector according to the determined first code word synchronization value and a predetermined symmetric key to construct a first dynamic check matrix; The transmitting end encodes the message to be sent according to the constructed first dynamic check matrix, and sends the encoded message to the receiving end, where the encoded message includes n sending codewords, where n is a positive integer; The receiving end determines a second codeword synchronization value of the i-th received codeword according to the second initialization vector, wherein the second initialization vector includes a preset synchronization margin, the synchronization margin is used to make the second codeword synchronization value less than or equal to the first codeword synchronization value, and i is a positive integer less than or equal to n; The receiving end generates a second pseudo-random vector according to the symmetric key and the second code word synchronization value to construct a second dynamic check matrix; The receiving end decodes the i-th received codeword in the message from the sending end according to the second dynamic check matrix to obtain the received plaintext of the i-th received codeword and the intermediate hard decision decoding result in the decoding process; The receiving end updates the second code word synchronization value of the (i+1)th received code word according to the intermediate hard decision decoding result and the second dynamic check matrix.

2. A synchronous encoding and decoding method, suitable for transmission of dynamic random matrices, characterized in that: include: The transmitting end determines the first code word synchronization value according to the preset first initialization vector and the sending code word sequence number; Generate a first pseudo-random vector according to the determined first codeword synchronization value and a predetermined symmetric key to construct a first dynamic check matrix; Encode the message to be sent according to the constructed first dynamic check matrix, and send the encoded message to the receiving end, wherein the encoded message includes n sending codewords, where n is a positive integer; Among them, the second codeword synchronization value of the i-th received codeword at the receiving end during synchronous encoding is determined according to the second initialization vector, i is a positive integer less than or equal to n, and the second initialization vector includes a pre-set synchronization margin, which is used to make the second codeword synchronization value less than or equal to the first codeword synchronization value.

3. The method according to claim 2, characterized in that The determining of the first codeword synchronization value comprises: The first initialization vector is summed with the sent codeword sequence number to obtain the first codeword synchronization value.

4. The method according to claim 2 or 3, characterized in that: The first initialization vector and the second initialization vector include: a shared random number determined in a predetermined manner.

5. The method according to claim 4, characterized in that: The first initialization vector is the encoder power-on time; The second initialization vector is the difference between the decoder power-on time and the synchronization margin.

6. A synchronous encoding and decoding method, suitable for transmission of dynamic random matrices, characterized in that: include: The receiving end determines a second codeword synchronization value of an i-th received codeword according to a second initialization vector, wherein the second initialization vector includes a preset synchronization margin, and the synchronization margin is used to make the second codeword synchronization value less than or equal to the first codeword synchronization value, and the i-th received codeword is the i-th codeword received by the receiving end; Generate a second pseudo-random vector according to the symmetric key and the second code word synchronization value to construct a second dynamic check matrix; The receiving end decodes the i-th received codeword in the message from the sending end according to the second dynamic check matrix to obtain the received plaintext of the i-th received codeword and the intermediate hard decision decoding result in the decoding process; updating the second code word synchronization value of the i+1th received code word according to the intermediate hard decision decoding result and the second dynamic check matrix; The first codeword synchronization value of the transmitting end of the synchronous coding is determined by the first initialization vector and the sending codeword sequence number.

7. The method according to claim 6, characterized in that The updating of the second codeword synchronization value of the (i+1)th received codeword comprises: The receiving end determines the number of check equations that do not satisfy the check relationship according to the intermediate hard decision decoding result of the i-th received codeword and the second dynamic check matrix; The receiving end determines whether the current second dynamic check matrix matches the received codeword by determining the number of check equations that do not satisfy the check relationship; The receiving end updates the second codeword synchronization values ​​of i+1 received codewords according to whether the current second dynamic check matrix matches the received codeword.

8. The method according to claim 7, characterized in that The determining whether the current second dynamic check matrix matches the received codeword includes: When the number of check equations that do not satisfy the check relationship is less than a preset error threshold, determining that the second dynamic check matrix matches the received codeword; When the number of check equations that do not satisfy the check relationship is greater than or equal to the error threshold, it is determined that the second dynamic check matrix fails to match the received codeword.

9. The method according to claim 8, characterized in that The updating of the second codeword synchronization value of the i+1 received codewords comprises: The receiving end determines that the current second dynamic check matrix matches the received codeword, determines that the codeword synchronization is successful, and updates The receiving end determines that the current second dynamic check matrix fails to match the received codeword, determines that the codeword synchronization fails, and updates Among them, Q ( d i) ec The upper right subscript in the middle indicates the received codeword number, Q ( d i) ec represents the second codeword synchronization value of the i-th received codeword.

10. The method according to any one of claims 6 to 9, characterized in that: The first initialization vector and the second initialization vector include: a shared random number determined in a predetermined manner.

11. The method according to claim 10, characterized in that: The first initialization vector is the encoder power-on time; The second initialization vector is the difference between the decoder power-on time and the synchronization margin.

12. The method according to any one of claims 6 to 9, characterized in that: The second code word synchronization value of the first received code word is Q ( d 1 e ) c =IV dec +1; Among them, Q ( d 1 e ) c The upper right subscript in the middle indicates the received codeword number, Q ( d 1 e ) c Indicates the second codeword synchronization value of the first received codeword, IV dec Represents the second initialization vector.

13. A computer storage medium storing a computer program, wherein the computer storage medium stores a computer program, and when the computer program is executed by a processor, the synchronous encoding and decoding method according to any one of claims 2 to 5 or 6 to 12 is implemented.

14. A terminal, comprising: A memory and a processor, wherein the memory stores a computer program; wherein, The processor is configured to execute the computer program in the memory; When the computer program is executed by the processor, the synchronous coding method according to any one of claims 2 to 5 or 6 to 12 is implemented.

15. A synchronous coding transmitter, suitable for dynamic random matrix oriented transmission, characterized in that: include: A first code word synchronization unit and a first pseudo-random vector generator; wherein, The first codeword synchronization unit is configured to: determine a first codeword synchronization value according to a preset first initialization vector and a transmitted codeword sequence number; The first pseudo-random vector generator is configured to generate a first pseudo-random vector according to a determined first code word synchronization value and a predetermined symmetric key to construct a first dynamic check matrix; The LDPC encoder is set to: encode the transmitted message according to the constructed first dynamic check matrix, and send the encoded message to the receiving end, wherein the encoded message includes n transmitted codewords, where n is a positive integer; Among them, the second codeword synchronization value of the i-th received codeword at the receiving end during synchronous encoding is determined according to the second initialization vector, i is a positive integer less than or equal to n, and the second initialization vector includes a pre-set synchronization margin, which is used to make the second codeword synchronization value less than or equal to the first codeword synchronization value.

16. A synchronous coding receiving end, suitable for transmission oriented to dynamic random matrix, characterized in that: include: A second code word synchronization unit, a second pseudo-random vector generator, and a low-density parity check code LDPC decoder; wherein, The second codeword synchronization unit is configured to: determine a second codeword synchronization value of an i-th received codeword according to a second initialization vector, wherein the second initialization vector includes a preset synchronization margin, and the synchronization margin is used to make the second codeword synchronization value less than or equal to the first codeword synchronization value, and the i-th received codeword is the i-th codeword received by the receiving end; The second pseudo-random vector generator is configured to generate a second pseudo-random vector according to the symmetric key and the second code word synchronization value to construct a second dynamic check matrix; The LDPC decoder is configured to: decode the i-th received codeword in the message from the transmitter according to the second dynamic check matrix to obtain the received plaintext of the i-th received codeword and the intermediate hard decision decoding result in the decoding process; update the second codeword synchronization value of the i+1-th received codeword according to the intermediate hard decision decoding result and the second dynamic check matrix; The first codeword synchronization value of the transmitting end of the synchronous coding is determined by the first initialization vector and the sending codeword sequence number.

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