Encryption and decryption communication system based on baseband superposition technology

Abstract

The invention relates to the technical field of encryption and decryption communication, and discloses an encryption and decryption communication system based on a baseband superposition technology, which comprises a baseband superposition module, a sequence scrambling module and a modulation module which are arranged at a sending end, the demodulation module, the sequence descrambling module and the iteration processing module are arranged at a receiving end. According to the invention, a baseband superposition encryption and decryption method is adopted, code word superposition is carried out at a sending end, information loss is caused, and the checkability of a coding sequence is destroyed in a large proportion, so that the difficulty of cracking a signal specification and obtaining communication information by a third receiver is greatly improved, and the anti-interception capability of information is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of encryption and decryption communication, and in particular to an encryption and decryption communication system based on baseband superposition technology. Background Art

[0002] With the rapid development of data communication, the application of non-cooperative communication is becoming more and more extensive. Because the air link part has the characteristics of openness, there are great security risks when information is transmitted. Information security is the premise of wireless communication transmission, and encryption technology, as an active information security prevention strategy, adopts corresponding encryption algorithms to convert plaintext into ciphertext for transmission, prevent unauthorized users from obtaining original data, and ensure the confidentiality and authenticity of data during storage and transmission. Existing sequence cipher designs usually use linear feedback shift registers and various nonlinear transformations to output key sequences to achieve the purpose of encrypting data. Correspondingly, various key cracking algorithms based on correlation attacks use verification equation solution and verification advantage statistics to complete key cracking. However, when the length of the register is relatively short, the algorithm is vulnerable to attack, thereby reducing the security of encryption.

[0003] Patent CN112134691A proposes a method, device and medium for implementing a NLCS block cipher with repeatable components. In this scheme, a linear feedback shift register and four nonlinear feedback shift registers connected in series in a ring are used to construct a key expansion algorithm, which improves the security of the key and the consistency of encryption and decryption. Patent CN113242118A proposes a data link encryption communication method based on the AES advanced encryption standard, which uses a linear feedback shift register to process the key seed to obtain a key to achieve encrypted communication of the data link. However, the above schemes all have the problem that the security of encryption will be reduced when the register length is short and the randomness is insufficient. Summary of the invention

[0004] In view of the above-mentioned deficiencies in the prior art, the present invention provides an encryption and decryption communication system based on baseband superposition technology.

[0005] In order to achieve the above-mentioned object of the invention, the technical solution adopted by the present invention is:

[0006] An encryption and decryption communication system based on baseband superposition technology, comprising:

[0007] A baseband superposition module, a sequence scrambling module and a modulation module are provided at the transmitting end; the baseband superposition module first performs serial-to-parallel conversion on the baseband signal and then uses a strong error correction code to encode each baseband signal, and then performs grouping accumulation bit by bit according to a preset superposition rule to obtain a baseband superposition signal; the sequence scrambling module is used to perform a sequence scrambling operation on the baseband superposition signal to obtain a baseband scrambled signal; the modulation module is used to perform a modulation operation on the baseband scrambled signal, and after obtaining the modulated signal, transmit it to the receiving end through a transmission channel;

[0008] A demodulation module, a sequence descrambling module and an iterative processing module are arranged at the receiving end; the demodulation module is used to perform a demodulation operation on the modulated signal to obtain a demodulated signal; the sequence descrambling module is used to perform a sequence descrambling operation on the demodulated signal to obtain a baseband superposition signal; the iterative processing module is used to perform a de-superposition operation on the baseband superposition signal according to a preset superposition rule during the iterative processing process, separate the bit information of each baseband signal, and then perform an error correction decoding operation to obtain a baseband signal.

[0009] Preferably, the baseband overlay module comprises:

[0010] Error correction coding unit and information superposition unit;

[0011] The information superposition unit is used to add the bit sequences corresponding to the baseband signals of each channel bit by bit according to a preset superposition rule.

[0012] Preferably, the adding bit by bit the bit sequences corresponding to the baseband signals of each channel according to a preset superposition rule comprises:

[0013] The full bit sequences corresponding to the baseband signals of each channel are added bit by bit, and the bit sequences of the designated intervals corresponding to the baseband signals of each channel are added bit by bit.

[0014] Preferably, the baseband superposition module inserts a bit interleaving unit between the error correction coding unit and the information superposition unit.

[0015] Preferably, the error correction coding unit uses low-density parity-check codes to encode each baseband signal.

[0016] Preferably, the sequence scrambling module uses a complex sequence scrambling method to perform sequence scrambling operation on the baseband superposition signal.

[0017] Preferably, the sequence descrambling module adopts a complex sequence scrambling method to perform sequence descrambling operation on the baseband superposition signal.

[0018] Preferably, the iterative processing module includes:

[0019] De-addition unit and error correction decoding unit;

[0020] The anti-addition unit is used to perform an anti-addition operation according to a preset addition rule to separate the bit information of each baseband signal.

[0021] Preferably, the iterative processing module inserts a bit deinterleaving unit between the anti-superposition unit and the error correction decoding unit.

[0022] Preferably, the error correction decoding unit uses low-density parity-check codes to decode each baseband signal.

[0023] The present invention has the following beneficial effects:

[0024] When the present invention performs parsing at the receiving end, due to the complexity and variability of the satellite communication system, a third-party attacker will take attack measures to obtain legitimate information, resulting in information leakage. The baseband superposition encryption and decryption method is adopted, and codeword superposition is performed at the sending end, resulting in information loss, which greatly destroys the verification of the coding sequence, making it much more difficult for the third recipient to crack the signal specifications and obtain the communication information, thereby improving the anti-interception capability of the information. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the structure of an encryption and decryption communication system based on baseband superposition technology;

[0026] Figure 2 A schematic diagram of the position of baseband overlay in system hierarchical peer-to-peer communication;

[0027] Figure 3 This is a schematic diagram of baseband superposition;

[0028] Figure 4 This is a schematic diagram of the baseband superposition process in units of 3 bits. DETAILED DESCRIPTION

[0029] The specific implementation modes of the present invention are described below so that those skilled in the art can understand the present invention. However, it should be clear that the present invention is not limited to the scope of the specific implementation modes. For those of ordinary skill in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the attached claims, these changes are obvious, and all inventions and creations utilizing the concept of the present invention are protected.

[0030] The present invention designs a baseband superposition anti-interception communication mechanism to solve the problem of secure transmission of information. The mechanism uses superposition technology to utilize the pseudo-randomness of the communication information itself in satellite communication to achieve lossy disturbance of the information, so that the third receiving party cannot correctly extract the communication information, thereby improving the anti-interception capability of the information and achieving the purpose of confidential communication. The baseband superposition technology is different from the traditional sequence cipher. Since the sending end performs codeword superposition, information loss occurs, which greatly destroys the verification of the coding sequence, making it much more difficult for the third receiving party to crack the signal specifications and obtain the communication information; however, due to the use of strong error correction coding, the normal receiving party can correctly correct the missing information and restore the transmitted information, thereby achieving the purpose of confidential communication against interception.

[0031] like Figure 1 As shown, an encryption and decryption communication system based on baseband overlay technology provided by an embodiment of the present invention includes:

[0032] A baseband superposition module, a sequence scrambling module and a modulation module are provided at the transmitting end; the baseband superposition module first performs serial-to-parallel conversion on the baseband signal and then uses a strong error correction code to encode each baseband signal, and then performs grouping accumulation bit by bit according to a preset superposition rule to obtain a baseband superposition signal; the sequence scrambling module is used to perform a sequence scrambling operation on the baseband superposition signal to obtain a baseband scrambled signal; the modulation module is used to perform a modulation operation on the baseband scrambled signal, and after obtaining the modulated signal, transmit it to the receiving end through a transmission channel;

[0033] A demodulation module, a sequence descrambling module and an iterative processing module are arranged at the receiving end; the demodulation module is used to perform a demodulation operation on the modulated signal to obtain a demodulated signal; the sequence descrambling module is used to perform a sequence descrambling operation on the demodulated signal to obtain a baseband superposition signal; the iterative processing module is used to perform a de-superposition operation on the baseband superposition signal according to a preset superposition rule during the iterative processing process, separate the bit information of each baseband signal, and then perform an error correction decoding operation to obtain a baseband signal.

[0034] like Figure 2 As shown in the figure, in the satellite communication system, it is divided into three main layers from bottom to top: physical layer, data link layer and network layer. Among them, the data link layer is composed of MAC sublayer and LAC sublayer. In essence, the system needs to effectively realize peer-to-peer communication between each layer, and baseband superposition is performed at the physical layer.

[0035] The mechanism of the present embodiment using the baseband superposition system to achieve anti-interception communication is: first use a strong error correction code to encode the information, and then perform group accumulation bit by bit (i.e., information superposition) to cause information loss. Information superposition and error correction coding are regarded as a cascade of two coding methods, and the coding parameters of the two methods are appropriately designed, and the information of the transmitting end is recovered by iterative decoding at the receiving end.

[0036] In an optional embodiment of the present invention, the baseband overlay module includes:

[0037] Error correction coding unit and information superposition unit;

[0038] The information superposition unit is used to add the bit sequences corresponding to the baseband signals of each channel bit by bit according to a preset superposition rule.

[0039] The step of adding bit sequences corresponding to the baseband signals of each channel bit by bit according to a preset superposition rule comprises:

[0040] The full bit sequences corresponding to the baseband signals of each channel are added bit by bit, and the bit sequences of the designated intervals corresponding to the baseband signals of each channel are added bit by bit.

[0041] The baseband superposition module inserts a bit interleaving unit between the error correction coding unit and the information superposition unit.

[0042] The baseband superposition technology principle adopted in this embodiment is as follows Figure 1 As shown, the basic principle can be described as follows: after the baseband data is input, it is first converted from serial to parallel, and then an arithmetic superposition operation is performed, and the superimposed baseband superposition signal ΔS is modulated and sent out, which is expressed as:

[0043] ΔS=S1+S2+S3+…S n

[0044] Among them, S N (N=1, 2, 3…n) represents the Nth baseband signal input, and ΔS is the baseband superimposed signal after the N baseband signals are superimposed.

[0045] If there are N baseband signals to be superimposed, the superposition diagram is as follows Figure 3As shown, after the N baseband signals are encoded and interleaved respectively, they are superimposed in the information superposition module. After the baseband superposition is completed, the baseband superposition signal ΔS is output, and then the modulation process is performed. The encoding adopts LDPC coding. LDPC coding is a forward error correction code. Its core lies in improving the reliability of data transmission by adding redundant data. Interleaving adopts channel interleaving. Interleaving uses an interleaving table to shuffle and rearrange the data to improve the reliability and anti-interference ability of data transmission. After encoding and interleaving operations, the stability and reliability of data transmission have been enhanced. Adding a baseband superposition transmission module makes data transmission more reliable and secure. The input of the baseband superposition module is the output of the N baseband signals after interleaving. At this time, the information sequence of the N baseband signals is 0 / 1 bit, that is, the superposition operation is to add the bit sequence of the interleaved N baseband signals bit by bit. The specific superposition range can be the bit-by-bit addition of the full bit sequence and the bit sequence of a partially specified interval. The position of the partially specified interval is arbitrary, and it can be a random number of consecutive bits at any position in the full bit sequence, such as Figure 4 As shown, the superposition method is determined by the sender and is notified to the reasonable receiver through any cryptographically secure method.

[0046] From the perspective of coding, this superposition operation can be regarded as a mathematical mapping, which can be described in the form of a mathematical graph. When designing the system, strong error correction coding can be used in conjunction with inserting a first-level interleaver between the encoder and the superposition mapping.

[0047] According to the Turbo iteration principle, for each subsystem of a system, as long as the following two conditions are met:

[0048] a) There are constraints or relationships between subsystems;

[0049] b) There is interweaving or hidden interweaving between subsystems;

[0050] That is, the inverse processes of each subsystem can be jointly processed using an iterative processing method, thereby achieving a large processing gain.

[0051] Although the superposition mapping causes information loss, for normal communication, the receiver can use the Turbo iteration principle to accurately recover the missing information under the condition of known system communication mode and signal specifications. This is because: According to Shannon's theorem, if the communication system wants to infinitely approach the Shannon limit, the following two conditions must be met:

[0052] a) Channel coding uses Shannon limit code - the code length is long enough, quasi-random coding, and maximum likelihood decoding is used;

[0053] b) Source coding has Gaussian distribution characteristics.

[0054] It is not difficult to see from the analysis of the superposition operation that the baseband superposition technology of this embodiment has exactly the following two conditions:

[0055] a) The strong error correction coding used in the system can achieve excellent performance close to the Shannon limit;

[0056] b) The superposition mapping causes the signal source to present a Gaussian-like distribution.

[0057] Therefore, under the combined effect of these two conditions, lossless recovery of missing information can be achieved. However, for a third-party attacker, the problem can be described as: given S1+S2+…S n and, respectively solve for S1, S2…, and S n Without any prior information, it is difficult for a third party to solve this problem. However, the legitimate receiver knows the superposition method and can correctly perform de-superposition according to the superposition method to separate each channel of information after receiving the information from the sender.

[0058] In an optional embodiment of the present invention, the error correction coding unit uses a low-density parity check code to encode each baseband signal.

[0059] Low-density parity check (LDPC) code is a low-density parity check code. With its excellent performance close to the Shannon limit, it has been widely used in various communication systems and is recognized by the industry as the end of coding theory. This embodiment intends to use low-density parity check code as the component code of baseband superposition.

[0060] In an optional embodiment of the present invention, the sequence scrambling module uses a complex sequence scrambling method to perform a sequence scrambling operation on the baseband superposition signal.

[0061] The sequence scrambling operation performed in this embodiment can be taken as complex sequence scrambling. In this way, when applied to an actual communication system, the modulation and demodulation function of the signal can be better realized.

[0062] In an optional embodiment of the present invention, the sequence descrambling module uses a complex sequence scrambling method to perform a sequence descrambling operation on the baseband superposition signal.

[0063] The iterative processing module comprises:

[0064] De-addition unit and error correction decoding unit;

[0065] The anti-addition unit is used to perform an anti-addition operation according to a preset addition rule. The anti-addition operation is to perform an opposite operation according to the addition strategy of the sender to separate the bit information of each baseband signal.

[0066] The iterative processing module inserts a bit deinterleaving unit between the anti-addition unit and the error correction decoding unit.

[0067] The error correction decoding unit decodes each baseband signal using a low-density parity check code.

[0068] When the legitimate receiver receives the information, it performs demodulation and sequence descrambling operations in sequence, and then enters the iterative processing link, that is, within the maximum number of times allowed, the anti-superposition process is performed repeatedly. If the anti-superposition does not correctly restore the data this time, the anti-superposition operation will be performed again next time. If the anti-superposition process correctly restores the data this time, the iterative cycle can be ended. Within the maximum number of iterations allowed, the anti-superposition operation is performed according to the superposition criteria provided by the sender to separate the bit information of each path, and then the bit deinterleaving and error correction decoding operations are performed. When the number of superimposed branches of the sender is large, due to binary addition, multiple results may appear for each branch when performing anti-superposition. At this time, decoding is performed according to the strong error correction of the LDPC code. When the check matrix of the LDPC code is all 0, this means that the decoding is successful, the source is restored, and the correct information is obtained.

[0069] When the present invention performs parsing at the receiving end, due to the complexity and variability of the satellite communication system, a third-party attacker will take attack measures to obtain legitimate information, resulting in information leakage. The baseband superposition encryption and decryption method is adopted, and codeword superposition is performed at the sending end, resulting in information loss, which greatly destroys the verification of the coding sequence, making it much more difficult for the third recipient to crack the signal specifications and obtain the communication information, thereby improving the anti-interception capability of the information.

[0070] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0071] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0072] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0073] The present invention uses specific embodiments to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the present invention.

[0074] Those skilled in the art will appreciate that the embodiments described herein are intended to help readers understand the principles of the present invention, and should be understood that the protection scope of the present invention is not limited to such specific statements and embodiments. Those skilled in the art can make various other specific variations and combinations that do not deviate from the essence of the present invention based on the technical revelations disclosed by the present invention, and these variations and combinations are still within the protection scope of the present invention.

Claims

1. An encryption and decryption communication system based on baseband superposition technology, characterized in that: include: A baseband superposition module, a sequence scrambling module and a modulation module are arranged at the transmitting end; The baseband superposition module first performs serial-to-parallel conversion on the baseband signal, then uses a strong error correction code to encode each baseband signal, and then performs grouping and bit-by-bit accumulation according to a preset superposition rule to obtain a baseband superposition signal; The sequence scrambling module is used to perform a sequence scrambling operation on the baseband superposition signal to obtain a baseband scrambled signal; The modulation module is used to perform a modulation operation on the baseband scrambled signal, and after obtaining the modulated signal, transmit it to the receiving end through the transmission channel; A demodulation module, a sequence descrambling module and an iterative processing module are arranged at the receiving end; the demodulation module is used to perform a demodulation operation on the modulated signal to obtain a demodulated signal; the sequence descrambling module is used to perform a sequence descrambling operation on the demodulated signal to obtain a baseband superposition signal; the iterative processing module is used to perform a de-superposition operation on the baseband superposition signal according to a preset superposition rule during the iterative processing process, separate the bit information of each baseband signal, and then perform an error correction decoding operation to obtain a baseband signal.

2. According to claim 1, the encryption and decryption communication system based on baseband superposition technology is characterized in that: The baseband overlay module comprises: Error correction coding unit and information superposition unit; The information superposition unit is used to add the bit sequences corresponding to the baseband signals of each channel bit by bit according to a preset superposition rule.

3. The encryption and decryption communication system based on baseband superposition technology according to claim 2 is characterized in that: The step of adding bit sequences corresponding to the baseband signals of each channel bit by bit according to a preset superposition rule comprises: The full bit sequences corresponding to the baseband signals of each channel are added bit by bit, and the bit sequences of the designated intervals corresponding to the baseband signals of each channel are added bit by bit.

4. The encryption and decryption communication system based on baseband superposition technology according to claim 2 is characterized in that: The baseband superposition module inserts a bit interleaving unit between the error correction coding unit and the information superposition unit.

5. The encryption and decryption communication system based on baseband superposition technology according to claim 2 is characterized in that: The error correction coding unit uses low-density parity check codes to encode the baseband signals of each channel.

6. The encryption and decryption communication system based on baseband superposition technology according to claim 1, characterized in that: The sequence scrambling module uses a complex sequence scrambling method to perform a sequence scrambling operation on the baseband superposition signal.

7. The encryption and decryption communication system based on baseband superposition technology according to claim 1 is characterized in that: The sequence descrambling module uses a complex sequence scrambling method to perform sequence descrambling operations on the baseband superposition signal.

8. The encryption and decryption communication system based on baseband superposition technology according to claim 1, characterized in that: The iterative processing module comprises: De-addition unit and error correction decoding unit; The anti-addition unit is used to perform an anti-addition operation according to a preset addition rule to separate the bit information of each baseband signal.

9. The encryption and decryption communication system based on baseband superposition technology according to claim 8, characterized in that: The iterative processing module inserts a bit deinterleaving unit between the anti-addition unit and the error correction decoding unit.

10. The encryption and decryption communication system based on baseband superposition technology according to claim 8, characterized in that: The error correction decoding unit decodes each baseband signal using a low-density parity check code.

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