WO2020168627A1 - Encryption and decryption method and device employing zipper-type dynamic hashing and nlfsr techniques - Google Patents

Abstract

An encryption and decryption method and device employing zipper-type dynamic hashing and NLFSR techniques. An encryption process comprises the following steps: using a nonlinear feedback function and a bit-manipulation Boolean function to pre-process a seed key, so as to form a keystream sequence; changing, according to the bit-manipulation Boolean function employing the keystream sequence, a bit value of a plaintext sequence, so as to form a pseudo-plaintext sequence; dividing, according to the keystream sequence, the pseudo-plaintext sequence into multiple pseudo-plaintext subsequences; and calculating, according to a hash mapping rule depending on the keystream sequence, a dynamic hash address corresponding to a binary bit of each respective pseudo-plaintext sequence, and mapping, by means of a hash function, the multiple pseudo-plaintext subsequences to a ciphertext space, so as to form a ciphertext stream sequence. The present application has the following beneficial effects: keystream generators, beside using nonlinear feedback shift registers, also use a bit-manipulation Boolean function so as to obtain keystreams having a longer period and improved randomness; moreover, bit-manipulation rules for plaintexts and mapping rules employing zipper-type dynamic hashing are used to increase the difficulty of decoding ciphertext stream sequences.

Description

Encryption and decryption method and device based on zipper type dynamic hash and NLFSR Technical field

This application relates to the field of information security, and in particular to an encryption and decryption method and device based on zipper dynamic hashing and NLFSR (Nonlinear Feedback Shift Register). This application can generally be used for network communication information encryption, aerospace digital remote control commands and data encryption, drone digital remote control communication data encryption, early warning aircraft digital communication command system information encryption, GPS satellite digital communication data encryption, mobile communication encryption, big data encryption , Graphic image encryption and email encryption, etc. After encryption, military, political, and diplomatic documents can be transmitted using civil communication networks to save file transmission costs.

Background technique

Stream cipher is usually a symmetric key technology. Because of its simple implementation and fast encryption speed, errors in ciphertext transmission will not spread in plaintext and other benefits, so it has become an important type of cryptosystem. Stream cipher is the mainstream cipher system used in the world's military and diplomatic fields. The design of the key stream generator is the key to the security of the stream cipher. At present, the more famous stream cipher algorithms include the A5 algorithm used in the European digital cellular mobile phone system GSM and the RC4 algorithm developed by the American RSA Data Security Company. Because stream cipher has many advantages that other ciphers cannot match, it is still one of the most common cipher systems today.

The design of the key stream generator for stream ciphers is the key to stream cipher technology. Its essence is to generate a key stream composed of 0 and 1 data streams through a given algorithm, usually based on a mathematical model that can generate pseudo-random sequences. Such as: algebraic operations, linear feedback shift register (LFSR, Linear Feedback Shift Register), clock control sequence, combined network sequence, cellular automata and chaos theory, etc. The sender encrypts the plaintext sequence with a key stream to generate a ciphertext and sends it to the receiver; the receiver uses the same key stream to decrypt the ciphertext to recover the plaintext sequence. At present, many scholars have mastered the means to attack and decipher the above encryption methods. For example, Courtois and Meier proposed to apply algebraic attacks to stream cipher algorithms based on linear feedback shift registers at the European Cryptography Annual Conference in 2003. As a new hot spot in the field of stream cipher research, "algebraic attack" analyzes the security of cryptosystems from a new perspective and transforms it into the problem of solving overdetermined multi-element systems. This has had a huge impact on the design of the traditional stream cipher system.

In order to resist related attacks and algebraic attacks, the stream cipher algorithm using linear feedback shift registers needs to use a more complex feedforward function, and nonlinear feedback shift registers as a pseudo-random sequence generator with high security can effectively resist Related attacks and algebraic attacks. After 2004, key stream generators based on nonlinear shift register technology began to emerge. For example, the algorithms Grain, Trivium, and MICKEY finally recommended by the eSTREAM project all use nonlinear feedback shift registers as key stream generators.

Since the key to conventional stream cipher technology is to construct a variety of key stream generators to generate (pseudo) random sequences as key stream sequences, attacks on stream ciphers are also concentrated on attacks on key stream generators. on. However, conventional stream cipher encryption and decryption methods are based on binary bit XOR operation. In other words, during encryption, the bit XOR operation between the plaintext sequence and the key stream sequence randomly turns 1 in the plaintext sequence into 0 and 0 into 1 to generate a ciphertext stream sequence; when decrypting, the ciphertext stream sequence The bitwise exclusive OR operation of the corresponding bits with the key stream sequence generates a plaintext sequence. Therefore, one of the drawbacks of this mechanism is that the security strength of the stream cipher depends entirely on the security strength of the key stream sequence, but there have been many attacks on the key stream generator. Another defect of this mechanism is that the encryption and decryption method is single, which leads to the fact that for a shorter key stream sequence, the ciphertext with better randomness and uniformity of code distribution cannot be obtained by relying solely on the exclusive OR operation.

Summary of the invention

The purpose of this application is to solve the shortcomings of the prior art, and provide an encryption and decryption method based on zipper dynamic hash and nonlinear feedback shift register and corresponding encryption and decryption device, so that the ciphertext has strong randomness and indispensability. Predictability, so as to obtain the technical effect of increasing the difficulty of deciphering the ciphertext.

In order to achieve the above objective, this application adopts the following technical solutions.

First, this application proposes an encryption and decryption method based on zipper dynamic hashing and NLFSR. The method can include the following steps:

S100) Preprocessing the seed key using a non-linear feedback function and a bit transformation Boolean function to form a key stream sequence;

S200) Changing the bit value of the plaintext sequence according to the bit transformation Boolean function based on the key stream sequence to form a pseudo-plaintext sequence;

S300) Divide the pseudo-plaintext sequence into multiple pseudo-plaintext sub-sequences according to the key stream sequence;

S400) According to the hash mapping rule that depends on the key stream sequence, calculate the dynamic hash address corresponding to the binary bit of each pseudo-plaintext sequence, and hash the pseudo-plaintext subsequences divided into multiple paths into the ciphertext space To form a sequence of ciphertext streams.

Because the key stream generator is constructed based on the nonlinear feedback shift register and bit transformation rules, and the nonlinear feedback shift register as a pseudo-random sequence generator with high security can effectively resist related attacks and algebraic attacks; so The above encryption method can effectively increase the difficulty of deciphering the ciphertext.

Further, in the above-mentioned method of the present application, it further includes the following steps for decryption:

S500) Obtain a ciphertext stream sequence, and use the same non-linear feedback function and the bit transformation Boolean function to preprocess a predetermined seed key to form a key stream sequence;

S600) According to the inverse hash mapping rule that depends on the key stream sequence, calculate the hash address corresponding to the binary bit of each ciphertext sequence, and map the ciphertext sequence hash to the plaintext storage space to form a multi-path pseudo Plaintext subsequence;

S700) Combine multiple pseudo-plaintext subsequences to form a pseudo-plaintext sequence;

S800) Changing the bit value of the pseudo-plaintext sequence according to the bit transformation Boolean function based on the key stream sequence to form the plaintext sequence.

Further, in the above method of the present application, the step S100 further includes the following sub-steps:

S101) Input the seed key to the nonlinear feedback function to generate the first output sequence;

S102) Loop the first output sequence to fill the second output sequence formed into the key stream sequence space;

S103) Input the second output sequence to transform the Boolean function in place to form a key stream sequence.

Still further, in the above method of the present application, in the step S102, the starting position of the circular filling is any legal position in the first output sequence.

Further, in the above method of the present application, the step S300 further includes the following sub-steps:

S301) The pseudo-plaintext sequence is decomposed into multiple pseudo-plaintext sub-sequences according to the true value bits and false value bits of the key stream sequence;

S302) The multi-path pseudo-plaintext sub-sequence and the key stream sequence are respectively scanned bidirectionally to dynamically hash the multi-path pseudo-plaintext sub-sequence into the ciphertext space in a zippered manner.

Alternatively, in the above-mentioned method of the present application, the plaintext sequence, the key stream sequence, and the ciphertext stream sequence all adopt the data structure of a circular queue, and encryption and decryption are performed from any legal data in the corresponding circular queue. The position starts.

Further, in the above method of the present application, the bit transformation Boolean function is a bitwise inverse function according to a specific bit of the key stream sequence.

Alternatively, in the above method of the present application, the nonlinear feedback function is a feedback function with an algebraic order of 4 or more.

Secondly, this application also proposes an encryption and decryption device based on zipper dynamic hashing and NLFSR. The device may include the following modules: a first key stream generation module for preprocessing the seed key using a non-linear feedback function and a bit transformation Boolean function to form a key stream sequence; a pseudo-plaintext generation module for generating The bit transformation Boolean function of the key stream sequence changes the bit value of the plain text sequence to form a pseudo-plain text sequence; the pseudo-plain text division module is used to divide the pseudo-plain text sequence into multiple pseudo-plain text sub-sequences according to the key stream sequence; the first dynamic dispersal The column module is used to calculate the dynamic hash address corresponding to the binary bit of each pseudo-plaintext sequence according to the hash mapping rules that depend on the key stream sequence, and hash the pseudo-plaintext sub-sequences divided into multiple paths to the cipher In the text space to form a ciphertext stream sequence.

Further, in the above-mentioned device of the present application, it further includes the following modules for decryption: the second key stream generation module obtains the ciphertext stream sequence, and uses the same nonlinear feedback function and the bit transformation Boolean function Preprocess the pre-appointed seed key to form a key stream sequence; the second dynamic hash module is used to calculate the corresponding binary bits of each ciphertext sequence according to the inverse hash mapping rule dependent on the key stream sequence Hash the address and map the ciphertext sequence to the plaintext storage space to form multiple pseudo-plaintext subsequences; pseudo-plaintext merge module, used to merge multiple pseudo-plaintext subsequences to form a pseudo-plaintext sequence; pseudo-plaintext The restoration module is used to change the bit value of the pseudo plaintext sequence according to the bit transformation Boolean function based on the key stream sequence to form the plaintext sequence.

Further, in the above-mentioned device of the present application, the key stream generation module further includes the following sub-modules: a first output module for inputting a seed key to a nonlinear feedback function to generate a first output sequence; a second output The module is used to loop the first output sequence to fill the second output sequence formed into the key stream sequence space; the displacement module is used to input the second output sequence to transform the Boolean function to form the key stream sequence.

Still further, in the above device of the present application, in the second output module, the starting position of the circular filling is any legal position in the first output sequence.

Further, in the above-mentioned device of the present application, the first dynamic hash module further includes the following sub-modules: a decomposition module for decomposing the pseudo-plaintext sequence into true value bits and false value bits of the key stream sequence A multi-path pseudo-plaintext sub-sequence; a hash module for scanning the multi-path pseudo-plain-text sub-sequence and the key stream sequence in a bidirectional cycle respectively to dynamically hash the multi-path pseudo-plaintext sub-sequence into the ciphertext space in a zippered fashion.

Alternatively, in the above-mentioned device of the present application, the plaintext sequence, the key stream sequence, and the ciphertext stream sequence all adopt the data structure of a circular queue, and encryption and decryption are performed from any legal data in the corresponding circular queue. The position starts.

Further, in the above device of the present application, the bit transformation Boolean function is a bitwise inverse function according to a specific bit of the key stream sequence.

Alternatively, in the above-mentioned device of the present application, the nonlinear feedback function is a feedback function with an algebraic order of 4 or more.

Finally, this application also proposes a computer-readable storage medium on which computer instructions are stored. When the above instructions are executed by the processor, the following steps are performed:

S100) Preprocessing the seed key using a non-linear feedback function and a bit transformation Boolean function to form a key stream sequence;

S200) Changing the bit value of the plaintext sequence according to the bit transformation Boolean function based on the key stream sequence to form a pseudo-plaintext sequence;

S300) Divide the pseudo-plaintext sequence into multiple pseudo-plaintext sub-sequences according to the key stream sequence;

S400) According to the hash mapping rule that depends on the key stream sequence, calculate the dynamic hash address corresponding to the binary bit of each pseudo-plaintext sequence, and hash the pseudo-plaintext subsequences divided into multiple paths into the ciphertext space To form a sequence of ciphertext streams.

Because the key stream generator is constructed based on the nonlinear feedback shift register and bit transformation rules, and the nonlinear feedback shift register as a pseudo-random sequence generator with high security can effectively resist related attacks and algebraic attacks; so The above encryption method can effectively increase the difficulty of deciphering the ciphertext.

Further, in the process in which the above-mentioned instructions of the present application are executed by the processor, the following steps for decryption are further included:

S500) Obtain a ciphertext stream sequence, and use the same non-linear feedback function and the bit transformation Boolean function to preprocess a predetermined seed key to form a key stream sequence;

S600) According to the inverse hash mapping rule that depends on the key stream sequence, calculate the hash address corresponding to the binary bit of each ciphertext sequence, and map the ciphertext sequence hash to the plaintext storage space to form a multi-path pseudo Plaintext subsequence;

S700) Combine multiple pseudo-plaintext subsequences to form a pseudo-plaintext sequence;

S800) Changing the bit value of the pseudo-plaintext sequence according to the bit transformation Boolean function based on the key stream sequence to form the plaintext sequence.

Further, in the process in which the above-mentioned instructions of the present application are executed by the processor, the step S100 further includes the following sub-steps:

S101) Input the seed key to the nonlinear feedback function to generate the first output sequence;

S102) Loop the first output sequence to fill the second output sequence formed into the key stream sequence space;

S103) Input the second output sequence to transform the Boolean function in place to form a key stream sequence.

Still further, during the execution of the above-mentioned instructions of the present application by the processor, in the step S102, the starting position of the loop filling is any legal position in the first output sequence.

Further, in the process in which the above-mentioned instructions of the present application are executed by the processor, the step S300 further includes the following sub-steps:

S301) Decomposing the pseudo-plaintext sequence into multiple pseudo-plaintext sub-sequences according to the key stream sequence;

S302) The multi-path pseudo-plaintext sub-sequence and the key stream sequence are respectively scanned bidirectionally to dynamically hash the multi-path pseudo-plaintext sub-sequence into the ciphertext space in a zippered manner.

Alternatively, during the execution of the above-mentioned instructions of the present application by the processor, the plaintext sequence, the key stream sequence, and the ciphertext stream sequence all adopt a circular queue data structure, and encryption and decryption are performed from the corresponding Start at any legal position in the circular queue.

Further, during the execution of the above-mentioned instructions of the present application by the processor, the bit transformation Boolean function is a bitwise inverse function according to a specific bit of the key stream sequence.

Alternatively, during the execution of the above-mentioned instructions of the present application by the processor, the nonlinear feedback function is a feedback function with an algebraic order of 4 or more.

The main difference between the technical solutions disclosed in this application and the traditional stream cipher encryption and decryption technology is that they do not rely on the exclusive OR operation of the plaintext and the key, but a zipper that relies on the key stream on the binary bit of the plaintext. Type dynamic hashing and bit transformation rules. This overcomes the traditional stream cipher encryption and decryption method is single, and the security strength of the stream cipher system completely depends on the security of the key stream. The existing attack technology on stream ciphers will no longer be applicable to the various technical solutions disclosed in this application. Therefore, the beneficial effect of this application is: by introducing a bit transformation rule in the key stream generator to change the bit value of the output sequence of the nonlinear feedback shift register, a key with longer period and better randomness is obtained. Streaming makes the uniformity of the ciphertext higher than that of the traditional stream cipher method, thereby obtaining the technical effect of increasing the difficulty of deciphering the ciphertext stream sequence.

Further, each technical solution disclosed in this application also has the following characteristics:

1. The encryption and decryption process can be easily implemented by encoding, and the time and space complexity of related algorithms is not higher than that of traditional methods;

2. The generated ciphertext stream sequence has strong randomness and unpredictability, and it is extremely difficult to decipher;

3. In this encryption method, the relationship between the plaintext stream sequence and the ciphertext stream sequence is not the traditional one-to-one, one-to-many relationship, but disordered encryption, that is, the relationship between the plaintext stream sequence and the ciphertext stream sequence is the most complicated Many-to-many relationship;

4. The uniformity of the ciphertext stream sequence is higher than the uniformity of the ciphertext stream sequence encrypted by the traditional stream cipher method;

5. Each encryption and decryption technology scheme respectively follows Shannon's one-time-one-pass cryptosystem;

6. The encrypted ciphertext stream sequence can be transmitted in the existing and open communication channel;

7. The corresponding security system can adopt the three separate principles of plaintext encryption, sending, and decryption to make the communication process more secure.

Description of the drawings

Figure 1 shows a flowchart of the encryption method based on zipper dynamic hashing and NLFSR disclosed in this application;

Figure 2 shows a schematic diagram of a communication process for implementing the method shown in Figure 1;

Figure 3 shows a flowchart of a sub-method of forming a key stream sequence in an embodiment of the present application;

FIG. 4 is a schematic diagram of the formation process of the key stream sequence shown in FIG. 3;

FIG. 5 shows a logical structure diagram of a non-linear feedback registration function in an embodiment of the application;

Figure 6 shows a schematic diagram of the generated key stream sequence;

Figure 7 shows a schematic diagram of the bit transformation process of a plaintext stream sequence;

FIG. 8 shows a flowchart of a sub-method of forming a ciphertext stream sequence in an embodiment of the present application;

FIG. 9 shows a schematic diagram of dynamic zippered hashing of multiple pseudo-plaintext subsequences into ciphertext space;

Figure 10 shows a schematic diagram of zipper-type dynamic hashing of a plaintext stream sequence;

Figure 11 shows a flow chart of a decryption method for a ciphertext stream sequence;

Figure 12 shows a schematic diagram of the reverse hashing of the ciphertext stream sequence into two paths for storage in the plaintext space;

Figure 13 is a schematic diagram of the bit transformation process of the pseudo-plaintext sequence;

Fig. 14 shows a block diagram of the encryption and decryption module based on zipper dynamic hashing and NLFSR disclosed in this application.

detailed description

The following is a clear and complete description of the concept, specific structure, and technical effects of the application in conjunction with the embodiments and drawings, so as to fully understand the purpose, solution, and effects of the application. It should be noted that the embodiments in this application and the features in the embodiments can be combined with each other if there is no conflict.

It should be noted that, unless otherwise specified, when a feature is called "fixed" or "connected" to another feature, it can be directly fixed and connected to another feature, or indirectly fixed or connected to another feature. One feature. In addition, the top, bottom, left, right and other descriptions used in this application are only relative to the mutual positional relationship of the various components of this application in the drawings. The singular forms "a", "the" and "said" used in this application and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

In addition, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art. The terminology used in this specification is only for describing specific embodiments, not for limiting the application. The term "and/or" as used herein includes any combination of one or more related listed items.

It should be understood that although the terms first, second, third, etc. may be used in this application to describe various elements, these elements should not be limited to these terms. These terms are only used to distinguish elements of the same type from each other. For example, without departing from the scope of the present application, the first element may also be referred to as the second element, and similarly, the second element may also be referred to as the first element. Depending on the context, the word "if" as used herein can be interpreted as "when" or "when".

In addition, for the convenience of discussion, the encryption and decryption methods and devices mentioned in this application involve five-tuples (M, C, K, E, D). In the five-tuple, M is a set of plaintext symbols, C is a set of cryptographic symbols, K is a set of reference byte symbols (also called a key set), E is a set of encryption algorithms, and D is a set of decryption algorithms . These collections have the following characteristics:

_1. M={M ₀ ,M ₁ ,...,M _len(M)-1 }={m ₀ ,m ₁ ,...,m _8len(M)-2 ,m _8×len(M)-1 }. Among them, len(M) is the number of bytes in the plaintext sequence. 8×len(M) is the binary number of the plaintext sequence. M _i (i∈[0,len(M)-1]) is a byte of the plaintext sequence. m _j ∈{0,1}, j∈[0,8×len(M)-1] is a binary bit of the plaintext sequence.

2. K={K ₀ ,K ₁ ,...,K _len(K)-1 }={key ₀ ,key ₁ ,...,key _8len(K)-2 ,key _8×len(K)-1 }. Among them, len(K) is the number of bytes in the key stream sequence. 8×len(K) is the binary number of the key stream sequence. K _i (i∈[0,len(K)-1]) is a byte of the key stream sequence. key _j ∈{0,1}, j∈[0,8×len(K)-1] is a binary bit of the key stream sequence.

3. C={C ₀ ,C ₁ ,...,C _len(C)-1 }={c ₀ ,c ₁ ,...,c _8len(C)-2 ,c _8×len(C)-1 }. Among them, len(C) is the number of bytes in the ciphertext stream sequence. len(C)=len(M), that is, the length of the plaintext sequence is equal to the length of the ciphertext stream sequence. 8×len(C) is the binary number of the ciphertext stream sequence. C _i (i∈[0,len(C)-1]) is a byte of the ciphertext stream sequence; c _j ∈{0,1}, j∈[0,8×len(C)- 1] is a binary bit (bit) of the ciphertext stream sequence.

4. The information in the M, K, and C sets is a byte symbol set composed of binary symbols {0, 1}. Among them, the number of symbol {1} in each set is denoted as sum(M), sum(K) and sum(C), and sum(M) is not necessarily equal to sum(C).

5. The elements of the encryption algorithm set E are a set of zipper hashing and bit transformation rules for encryption operations.

6. The element of the decryption algorithm set D is a set of zipper hash and bit transformation rules used for decryption operations, where the rules in set E should correspond to unique rules in set D, and the encryption rules and decryption rules are Reciprocal.

An obvious shortcoming of the traditional stream cipher method is that the encryption and decryption method is single, and the security strength of the stream cipher system depends entirely on the security of the key stream. There have been many attacks on the key stream generator. Another drawback is that for a short key stream, relying solely on the exclusive OR operation cannot obtain a ciphertext with better randomness and uniform code distribution.

The difference between this method and the traditional stream cipher encryption and decryption technology is that it does not rely on the exclusive OR operation of the plaintext and the key, but a kind of "zipper-style" hash and bit transformation of the plaintext on the binary bits that depends on the key stream. Rules, this overcomes the traditional stream cipher encryption and decryption method is single, and the security strength of the stream cipher system completely depends on the security of the key stream, the existing attack technology on the stream cipher will not be suitable for this method. In addition, bit transformation Boolean function combined with nonlinear feedback function can improve the period and randomness of the key stream. Specifically, referring to the method flowchart shown in FIG. 1 and the application scenario schematic diagram shown in FIG. 2, the encryption and decryption method based on zipper dynamic hashing and NLFSR disclosed in this application includes the following steps:

S100) Preprocessing the seed key using a non-linear feedback function and a bit transformation Boolean function to form a key stream sequence;

S200) Changing the bit value of the plaintext sequence according to the bit transformation Boolean function based on the key stream sequence to form a pseudo-plaintext sequence;

S300) Divide the pseudo-plaintext sequence into multiple pseudo-plaintext sub-sequences according to the key stream sequence;

S400) According to the hash mapping rule that depends on the key stream sequence, calculate the dynamic hash address corresponding to the binary bit of each pseudo-plaintext sequence, and hash the pseudo-plaintext subsequences divided into multiple paths into the ciphertext space To form a sequence of ciphertext streams.

The above encryption method is mainly based on the following principles:

1. The key stream generator is constructed based on a nonlinear feedback shift register and a bit-transformed Boolean function. As a pseudo-random sequence generator with high security, the nonlinear feedback shift register can effectively resist related attacks and algebraic attacks. The introduction of the bit transformation Boolean function is used to change the bit value of the key stream, thereby obtaining a longer cycle and better random key; in addition, the complexity of the nonlinear feedback shift register is high, so far there is no universally applicable Means of algebraic attacks against it;

2. The output sequence of the non-linear feedback shift register is periodic. For a seed key of length n, the period of the output sequence can be as long as 2 ⁿ -1. We introduce a bit transformation Boolean function to change the bit of the key stream. Therefore, this method does not require the design of an optimal nonlinear feedback shift register to achieve a better average performance.

3. Change the bit value of the plaintext according to the bit operation rules that depend on the key stream; on the basis of the bit-transformed plaintext stream that has been obtained, map it to the zipper-type hash mapping rule that depends on the key stream. The ciphertext is obtained in the ciphertext space; zipper-type dynamic hashing adopts the idea of n-way merging, randomly merging the binary bits that meet the conditions, thereby disturbing the sequence of the binary code of the plaintext stream after bit conversion, and the hash mapping rules are The design method is flexible and diverse, which is different from the previous stream cipher method based on a single XOR operation;

4. There is no specific correspondence between ciphertext and plaintext obtained by using this technology. There is the most complex network relationship (many-to-many relationship) between plaintext characters and ciphertext characters, which will effectively increase the difficulty of deciphering the ciphertext. This encryption method breaks the one-to-one and one-to-many relationship between plaintext and ciphertext in the traditional encryption method, but is disordered encryption;

5. This method can also use multi-key encryption, and the initial ciphertext is used as a parameter to perform multiple encryptions to obtain the final ciphertext, which further improves the security of information and better meets the ever-increasing demand for information encryption. In addition, the key can be placed in the hands of different people to ensure that the plaintext is more secure.

Therefore, as discussed above, there is no byte correspondence between the plaintext set M and the ciphertext set C in this method. To crack a file encrypted using this method, the four necessary and sufficient conditions that must be met are:

(1) The secret key generated by the nonlinear feedback shift register and the bit transformation Boolean function is known;

(2) Known bit transformation rules for decryption;

(3) Known zipper-type dynamic hashing rules for decryption;

(4) Known ciphertext files.

It is difficult to obtain the above four conditions at the same time. The experimental results prove that our method is simple and easy to implement and has high security.

Referring to the intention shown in Figure 2, first, the output sequence obtained by preprocessing the seed key by the nonlinear feedback shift register and the bit transformation Boolean function is used as the key stream. Then, the bit value of the plaintext is changed according to the bit conversion rule that depends on the key stream sequence. On the basis of the bit-transformed plaintext stream that has been obtained, according to the zipper-type hash mapping rule that depends on the key stream, calculate the hash address of each plaintext binary bit, and map it to the ciphertext space according to the hash address In, so as to get the ciphertext stream sequence. It is also possible to try to perform multiple grouping hashes with the initial ciphertext stream sequence C as a parameter to obtain the ciphertext stream sequence C ⁿ after multiple encryptions, which further improves the randomness and unpredictability of the information. If the encryption and decryption system only relies on hash rules for encryption, it is easy to decipher when transmitting special signals, such as all 0 values or all 1 values. The introduction of bit transformation rules for plaintext sequences can prevent this from happening. Using this method, not only can the discretely distributed ciphertext stream sequence be obtained, but the use of hash function and bit transformation Boolean function makes the code uniformity of the ciphertext stream sequence much higher than that of the plaintext sequence.

In the foregoing one or more embodiments of the present application, referring to the sub-method flowchart shown in FIG. 3, the step S100 further includes the following sub-steps:

S101) Input the seed key to the nonlinear feedback function to generate the first output sequence;

S102) Loop the first output sequence to fill the second output sequence formed into the key stream sequence space;

S103) Input the second output sequence to transform the Boolean function in place to form a key stream sequence.

Although the nonlinear feedback shift register (NLFSR) and linear feedback shift register (LFSR) are based on gate circuits (from the perspective of algebraic expression, the exclusive OR gate is represented as binary addition, and the AND gate is represented as binary multiplication) ; However, the difference between NLFSR and LFSR is that the feedback logic of NLFSR is composed of XOR gates and AND gates, while the feedback logic of LFSR is only composed of XOR gates. This leads to higher complexity of the nonlinear feedback shift register, and there is no universally applicable algebraic attack method for the nonlinear feedback shift register. In addition, the output sequence of the nonlinear feedback shift register is periodic. For a seed key of length n, the period of the output sequence can be as long as 2 ⁿ -1. The above method changes the bit value of the key stream by introducing a bit transformation Boolean function, thereby obtaining a key stream with longer period and better randomness. Therefore, the above method does not need to design an optimal nonlinear feedback shift register, and achieves better average performance.

Specifically, referring to the schematic diagram shown in FIG. 4, assuming that the files all use the extended ASCII code (IBM extended character set) as the encoding method, the seed key Seed_Key={1000} ₂ goes through the nonlinear feedback function F ₁ (x ₀ ,x ₁ , x ₂ , x ₃ ) generate the first output sequence S, the first output sequence S is cyclically filled into the key stream sequence to obtain the second output sequence S', and the second output sequence S'is bit transformed by the Boolean function F ₂ ( j) After processing (the 4th-order nonlinear feedback register corresponding to the bit transformation Boolean function is shown in Figure 5, where

Represents the exclusive OR operation, and "·" represents the seed of the multiplication operation), the key stream sequence K is obtained. Perform bit transformation on the plaintext sequence M with reference to the key stream sequence K to obtain M', and then perform zipper dynamic hashing on the transformed plaintext sequence M'according to the key stream sequence K, and finally obtain the ciphertext stream sequence C.

Seed_Key={1000} ₂

F ₂ (j)=((C ₁ +X ₁ ×j)MOD Y ₁ ＝＝Z ₁ ||(C ₂ +X ₂ ×j)MOD Y ₂ ＝＝Z ₂ )

S={101111010011000}

M="aaaa"={0X61,0X61,0X61,0X61} ₁₆ = {01100001,01100001,01100001,01100001} ₂ .

Referring to the schematic diagram of the key stream sequence shown in Figure 6, the schematic diagram of the bit transformation process of the plaintext stream sequence shown in Figure 7 and the flowchart of the sub-method forming the ciphertext stream sequence shown in Figure 8, the seed key is processed by the F ₁ function Then get the first output sequence S. S={101111010011000} ₂ is the first output sequence of the nonlinear feedback function F ₁ , and its period length is 2 ⁴ -1=15.

Is the intermediate result of the first output sequence S cyclically filling the key stream sequence space, that is, the extended ASCII code (hexadecimal) of the second output sequence S', S'is {0XBD,0X31,0X7A,0X62} ₁₆ , Convert it to binary to get {10111101,00110001,01111010,01100010} ₂ . The starting position of the cyclic filling can be any legal position in the first output sequence S. In this example, the starting position of the cyclic filling is set as the first item of the first output sequence S. F ₂ (j) is a Boolean function, in this example F ₂ (j)=((C ₁ +X ₁ ×j)MOD Y ₁ ＝＝Z ₁ ||(C ₂ +X ₂ ×j)MOD Y ₂ ＝ =Z ₂ ), where "MOD" means remainder operation, "==" means judgment equal operation, and "||" means logical OR operation. j is called the "bit order", which is the number of the binary bits of the key stream, starting from 0 in this example. C ₁ , X ₁ , Y ₁ , Z ₁ , C ₂ , X ₂ , Y ₂ , Z ₂ are predetermined integers, in this example the value is 0,1,4,0,0,1,7 , 0.

Represents the key stream sequence, which is the second output sequence S'processed by the F ₂ function to obtain the output sequence. Its extended ASCII code (hexadecimal) is {0X34,0XBB,0XF6,0XEA} ₁₆ , convert it to binary to get {00110100,10111011,11110110,11101010} ₂ , as shown in Figure 6. M="aaaa" represents a plaintext sequence, which is an encrypted input sequence. {0X61,0X61,0X61,0X61} ₁₆ is the extended ASCII code (hexadecimal) of the plaintext sequence "aaaa", convert it to binary to get {01100001,01100001,01100001,01100001} ₂ , as shown in Figure 7.

Represents the pseudo-plaintext sequence generated by bit-inverting part of the binary bits of the plaintext according to the specific bits of the key stream sequence ("false" value binary bits). {0XAA,0X25,0X68,0X74} ₁₆ is the extended ASCII code (hexadecimal) of the pseudo-plaintext sequence M', which is converted to binary to obtain {10101010,00100101,01101000,01110100} ₂ , as shown in Figure 7.

Represents the ciphertext stream sequence, which is the encrypted output sequence. {0X94,0XD0,0XDB,0X0C} ₁₆ is the ciphertext stream sequence

The extended ASCII code (hexadecimal) of, convert it to binary to get {10010100,11010000,11011011,00001100} ₂ , as shown in Figure 10.

The plaintext sequence, key stream sequence, and ciphertext stream sequence all adopt a logical structure shaped like a circular queue, which can be calculated at any position in the queue. Now the working pointers p1 and p2 point to the plaintext binary bits M[0], M[31], q1 and q2 point to key binary bits K[0], K[31], and road points to ciphertext binary bit C[0]. In this example, the bit conversion rule applied to the plaintext is: according to the specific bit of the key K, the bit-wise inversion, in this example, the "false" value binary bit. Figure 7 shows that according to the "false" bit of the key K, the corresponding bit of the plaintext M is reversed to obtain the pseudo-plaintext sequence M'.

Zipper hashing uses the idea of n-way merging. Randomly merge the binary bits that meet the conditions, thereby disturbing the sequence of the binary code of the pseudo-plaintext sequence. For the convenience of discussion and display, in this example, n=2, the pseudo-plaintext sequence M'is divided into two paths according to the key stream sequence K, and the pseudo-plaintext sequence M'and the key stream sequence K'are scanned cyclically in both directions to set the work The pointers p1 and p2, whose initial value can take any legal position in the circular queue, the pointer p1 looks for the "true" value bit in the key stream sequence, and the road1 is formed by M'[p1]; the pointer p2 looks for the key stream sequence The "false" value bit is composed of M'[p2] road2, as shown in Figure 9. The ciphertext space C is the road shown in FIG. 9. The binary codes of road1 and road2 in Fig. 7 are mapped to the ciphertext space C according to the zipper-type dynamic hash method, and the finally obtained ciphertext stream sequence is shown in Fig. 10.

Decryption is the inverse operation of the encryption process. By scanning the key stream sequence and the ciphertext stream sequence, calculate the hash address corresponding to the binary bit of each ciphertext stream sequence, and map the ciphertext stream sequence hash to the plaintext storage space , To form multiple pseudo-plaintext subsequences; merge multiple pseudo-plaintext subsequences to form a pseudo-plaintext sequence; change the bit value of the pseudo-plaintext sequence according to the bit transformation Boolean function based on the key stream sequence to form a plaintext sequence. Referring to the method flowchart shown in FIG. 11, in one or more embodiments of the present application, the following steps for decryption are further included:

S500) Obtain a ciphertext stream sequence, and use the same non-linear feedback function and the bit transformation Boolean function to preprocess a predetermined seed key to form a key stream sequence;

S600) According to the inverse hash mapping rule that depends on the key stream sequence, calculate the hash address corresponding to the binary bit of each ciphertext sequence, and map the ciphertext sequence hash to the plaintext storage space to form a multi-path pseudo Plaintext subsequence;

S700) Combine multiple pseudo-plaintext subsequences to form a pseudo-plaintext sequence;

S800) Changing the bit value of the pseudo-plaintext sequence according to the bit transformation Boolean function based on the key stream sequence to form the plaintext sequence.

Specifically, referring to the schematic diagrams shown in FIGS. 12 and 13, the seed key Seed_Key, the non-linear feedback function F ₁ (x ₀ , x ₁ , x ₂ , x ₃ ), the bit transformation Boolean function F ₂ (j), and The initial values of each item are the same as those during encryption, and the resulting key stream is also the same, as shown in Figure 6.

Represents the key stream, which is the output sequence obtained after the sequence S'is processed by the F ₂ function. Its extended ASCII code (hexadecimal) is {0X34,0XBB,0XF6,0XEA} ₁₆ , convert it to binary to get {00110100,10111011,11110110,11101010} ₂ , as shown in Figure 12.

Represents ciphertext, which is the decryption input sequence. {0X94,0XD0,0XDB,0X0C} ₁₆ is the ciphertext

The extended ASCII code (hexadecimal) of, convert it to binary to get {10010100,11010000,11011011,00001100} ₂ , as shown in Figure 12.

It is a pseudo-plaintext sequence obtained by ciphertext C according to the position swap rule. {0XAA,0X25,0X68,0X74} ₁₆ is the extended ASCII code (hexadecimal) of M', convert it to binary to get {10101010,00100101,01101000,01110100} ₂ . M="aaaa" represents the plaintext sequence, which is the decrypted output sequence. {0X61,0X61,0X61,0X61} ₁₆ is the extended ASCII code (hexadecimal) of the plaintext "aaaa", convert it to binary to get {01100001,01100001,01100001,01100001} ₂ . The plaintext sequence, the key stream sequence and the ciphertext stream sequence all adopt a logical structure like a circular queue, which can be calculated at any position in the queue. Now the working pointers p1 and p2 point to the plaintext sequence binary bits M[0], M[31] , Q1, q2 point to key binary bits K[0], K[31], road points to ciphertext binary bit C[0]. Zipper hashing uses the idea of n-way merging. To facilitate discussion, in this example n=2, the ciphertext stream sequence C is divided into two paths according to the key stream sequence K and stored in the plaintext space. One-way scanning of ciphertext space C, setting of working pointer road, two-way circular scanning of pseudo-plaintext sequence M', key stream sequence K', setting working pointers p1 and p2, the initial value of each pointer is the same as that of encryption, pointer p1 looks for the key For the truth bits in the stream sequence, C[road] is stored in M'[p1], and the road pointer and p1 pointer are moved; the pointer p2 looks for false value bits in the key stream sequence, and C[road] is stored in M'[p2 ], move the road pointer and the p2 pointer, and the final pseudo-plaintext sequence M'is shown in Figure 12. In this example, the bit transformation rule applied to the pseudo-plaintext sequence M'is: according to the specific bit of the key stream sequence K, the bit-wise inversion, in this example, it is a binary bit with a "false" value. Figure 13 shows that the plaintext sequence M is obtained by bit-inverting the corresponding bits of the pseudo-plaintext sequence M'according to the "false" value bits of the key K.

Referring to the module structure diagram shown in Figure 14 and the application scenario diagram shown in Figure 2, the encryption and decryption method based on zipper dynamic hashing and NLFSR disclosed in this application includes the following modules: a key stream generation module, which is used to use nonlinear The feedback function and the bit transformation Boolean function preprocess the seed key to form a key stream sequence; the pseudo-plaintext generation module is used to change the bit value of the plaintext sequence according to the bit transformation Boolean function based on the key stream sequence to form a pseudo-plaintext sequence ; Pseudo-plaintext division module, used to divide the pseudo-plaintext sequence into multiple pseudo-plaintext sub-sequences according to the key stream sequence; ciphertext stream generation module, used to calculate each The binary bits of the pseudo-plaintext sequence correspond to a dynamic hash address, and the multiplexed pseudo-plaintext subsequences are hashed into the ciphertext space to form a ciphertext stream sequence.

Based on the above encryption and decryption methods, the algorithm implementation of the encryption and decryption methods is as follows:

1 The algorithm implementation process of the encryption system

(1) Read the plaintext file and set the seed key

(2) Establish character pointer

Dynamic pointer to plaintext string array: char*M;

Dynamic pointer to key string array: char*K;

Dynamic pointer to ciphertext string array: char*C;

(3) Open the plaintext file M, count the bytes of the plaintext file M, and store it in M_bytes

(4) Allocate storage space

Plaintext storage space M=new char[M_bytes+1];

Key storage space K=new char[M_bytes+1];

Ciphertext storage space C=new char[M_bytes+1];

(5) Read the content of the plaintext file into the storage space pointed by pointer M

(6) Realize the function of writing 0 to the nth binary bit of the string

Create function: void write_bit_0(char*p_str,int n)

Function parameters: p_str is a pointer to a character string, and the parameter n represents a binary bit with a subscript of n

Function: Write 0 to the nth bit (bit) of the string pointed to by p_str

Function return value: empty

(7) Realize the function of writing 1 to the nth binary bit of the string

Create function: void write_bit_1(char*p_str,int n)

Function parameters: p_str is a pointer to a character string, and the parameter n represents a binary bit with a subscript of n

Function: Write the nth bit (bit) of the string pointed to by p_str into 1

Function return value: empty

(8) Realize the function of reading the nth binary bit of the string

Establishment function: int read_bit(char*p_str,int n)

Function parameters: p_str is a pointer to a character string, and the parameter n represents a binary bit with a subscript of n

Function: Find and return the value of the nth bit (bit) in the string pointed to by p, 0 or 1

Function return value: return the value 0 or 1 of the nth bit of the string pointed to by p

(9) Calculate the first output sequence of the seed key through the nonlinear feedback function

Create function: void get_NLFSR_sequence(string str, int a, int b, int c, int d)

Function parameters: str is the seed key, a, b, c, d are the non-linear feedback function F ₁ (x ₀ ,x ₁ ,...,x _n-1 )=x ₀ ⊕x _a ⊕x _b ⊕x _c · coefficient of x _d

Function: Calculate the first output sequence of the seed key through the nonlinear feedback function, and store it in the string NlfsrSequence

Function return value: None

Key sentence sequence:

(10) Initialize the key stream K, loop the first output sequence to fill the second output sequence formed into the key stream sequence space

Create function: void get_key_stream(string Seq)

Function parameter: Seq is the first output sequence character string generated by the non-linear feedback function of the seed key, consisting of two characters: ‘0’ and ‘1’;

Function function: Convert the output sequence Seq of the nonlinear feedback function into a character string, and store it in the key space K in a circular filling method

Number return value: none

Key sentence sequence:

(11) Simultaneously perform bit transformation on the plaintext stream of the second output sequence to obtain the key stream sequence and the pseudo-plaintext sequence

Create function void en_bit_transfor()

Function parameters: none

Function: simultaneously complete the bit transformation of the second output sequence and the plaintext stream M to obtain the key stream K and the pseudo-plaintext stream M'.

The bit transformation Boolean function of the key stream is: F ₂ (j)=((C ₁ +X ₁ ×j)MOD Y ₁ ＝＝Z ₁ ||(C ₂ +X ₂ ×j)MOD Y ₂ ＝＝Z ₂ ). The bit conversion rule of the plaintext is: according to the false value bit of the key stream K, the corresponding binary bit of the plaintext is inverted

Function return value: None

Key sentence sequence:

(12) Traverse the pseudo-plaintext and the key stream in one pass, and map the pseudo-plaintext to the ciphertext space according to the zipper-type dynamic hash rule

Create function: void en_zipper_hash(int road1,int road1)

Function parameters: road1 and road1 are the initial values of the working pointers, which are also the starting positions for splitting the plaintext into 2-way

Function: Divide the pseudo-plaintext M’ into two paths according to the key stream K, then merge the two-path pseudo-plaintext into the ciphertext space C to obtain the ciphertext

Function return value: None

Key sentence sequence:

(13) Complete the encryption, write the contents of the ciphertext array C into the ciphertext file and save

2 The algorithm implementation process of the decryption system

(1) Read in the ciphertext file and the initial key file

(2) Establish character pointer

Dynamic pointer to plaintext string array: char*M_decrypt;

Dynamic pointer to key string array: char*K;

Dynamic pointer to ciphertext string array: char*C;

(3) Open the ciphertext file C, count the bytes of the ciphertext file C, and store it in C_bytes

(4) Allocate storage space

Decrypted plaintext storage space M_decrypt=new char[C_bytes+1];

Key storage space K=new char[C_bytes+1];

The ciphertext storage space C=new char[C_bytes+1];

(5) Read the content of the ciphertext file into the storage space pointed to by pointer C

(6) Realize the function of writing 0 to the nth binary bit of the string

Create function: void write_bit_0(char*p_str,int n)

Function parameters: p_str is a pointer to a character string, and the parameter n represents a binary bit with a subscript of n

Function: Write 0 to the nth bit (bit) of the string pointed to by p_str

Function return value: empty

(7) Realize the function of writing 1 to the nth binary bit of the string

Create function: void write_bit_1(char*p_str,int n)

Function parameters: p_str is a pointer to a character string, and the parameter n represents a binary bit with a subscript of n

Function: Write the nth bit (bit) of the string pointed to by p_str into 1

Function return value: empty

(8) Realize the function of reading the nth binary bit of the string

Establishment function: int read_bit(char*p_str,int n)

Function parameters: p_str is a pointer to a character string, and the parameter n represents a binary bit with a subscript of n

Function: Find and return the value of the nth bit (bit) in the string pointed to by p, 0 or 1

Function return value: return the value 0 or 1 of the nth bit of the string pointed to by p

(9) Calculate the first output sequence of the seed key through the nonlinear feedback function

Create function: void get_NLFSR_sequence(string str, int a, int b, int c, int d)

Function parameters: str is the seed key, a, b, c, d are non-linear feedback functions

Coefficient of

Function: Calculate the first output sequence of the seed key through the nonlinear feedback function, and store it in the string NlfsrSequence

Function return value: None.

Key sentence sequence: void get_NLFSR_sequence(string str, int a, int b, int c, int d) function of the same encryption process, no more details

(10) Initialize the key stream K, loop the first output sequence to fill the second output sequence formed into the key stream sequence space

Create function: void get_key_stream(string Seq)

Function parameter: Seq is the first output sequence character string generated by the non-linear feedback function of the seed key, consisting of two characters: ‘0’ and ‘1’;

Function function: Convert the output sequence Seq of the non-linear feedback function into a character string, and store it in the key space K by means of circular filling.

Number return value: None.

Key sentence sequence: void get_key_stream(string Seq) function in the same encryption process, no more details

(11) Traverse the ciphertext and key stream in one pass, and map the ciphertext to the plaintext space according to the reverse zipper dynamic hash

Create function: void de_zipper_hash(int road1,int road2)

Function parameters: road1 and road1 are the initial value of the working pointer, and also the starting position of the 2-way merged ciphertext

Function function: merge the ciphertext C into the plaintext space M according to the key stream K, thereby obtaining the pseudo-plaintext sequence M’

Function return value: None

Key sentence sequence:

(12) Inverse bit transformation of pseudo-plaintext sequence

Create function void de_bit_transfor()

Function parameters: none

Function: complete the bit transformation of the pseudo-plaintext sequence M’ to obtain the plaintext sequence M

The bit conversion rule of the plaintext is: according to the false value bit of the key stream K, the corresponding binary bit of the plaintext is inverted

Function return value: None

Key sentence sequence:

(13) Decryption is completed, and the content of the plaintext array M_decrypt is written into the plaintext file and saved

A person of ordinary skill in the art may be aware that the units and algorithm steps of the examples described in combination with the embodiments disclosed herein can be implemented by electronic hardware or a combination of computer software and electronic hardware. Whether these functions are executed by hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians can use different methods for each specific application to implement the described functions, but such implementation should not be considered as going beyond the scope of the present invention.

In the embodiments provided by the present invention, it should be understood that the disclosed device and method may be implemented in other ways. For example, the system embodiment described above is merely illustrative. For example, the division of the modules or units is only a logical function division. In actual implementation, there may be other division methods, for example, multiple units or components may be Combined or can be integrated into another system, or some features can be ignored or not implemented. In addition, the displayed or discussed mutual coupling or direct coupling or communication connection may be indirect coupling or communication connection through some interfaces, devices or units, and may be in electrical, mechanical or other forms.

The units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the objectives of the solutions of the embodiments.

In addition, the functional units in the various embodiments of the present invention may be integrated into one processing unit, or each unit may exist alone physically, or two or more units may be integrated into one unit. The above-mentioned integrated unit can be implemented in the form of hardware or software functional unit.

If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer readable storage medium. Based on this understanding, the present invention implements all or part of the processes in the above-mentioned embodiments and methods, and can also be completed by instructing relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium. When the program is executed by the processor, the steps of the foregoing method embodiments can be implemented. Wherein, the computer program includes computer program code, and the computer program code may be in the form of source code, object code, executable file, or some intermediate forms. The computer-readable medium may include: any entity or device capable of carrying the computer program code, recording medium, U disk, mobile hard disk, magnetic disk, optical disk, computer memory, read-only memory (ROM, Read-Only Memory) , Random Access Memory (RAM, Random Access Memory), electrical carrier signal, telecommunications signal, and software distribution media, etc. It should be noted that the content contained in the computer-readable medium can be appropriately added or deleted in accordance with the requirements of the legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to the legislation and patent practice, the computer-readable medium Does not include electrical carrier signals and telecommunication signals.

The above-mentioned embodiments are only used to illustrate the technical solutions of the present invention, not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that it can still implement the foregoing The technical solutions recorded in the examples are modified, or some of the technical features are equivalently replaced; these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should be included in Within the protection scope of the present invention.

Claims (10)

1. An encryption and decryption method based on zipper dynamic hashing and NLFSR, which is characterized in that it includes the following steps:

   S100) Preprocessing the seed key using a non-linear feedback function and a bit transformation Boolean function to form a key stream sequence;

   S200) Changing the bit value of the plaintext sequence according to the bit transformation Boolean function based on the key stream sequence to form a pseudo-plaintext sequence;

   S300) Divide the pseudo-plaintext sequence into multiple pseudo-plaintext sub-sequences according to the key stream sequence;

   S400) According to the hash mapping rule that depends on the key stream sequence, calculate the dynamic hash address corresponding to the binary bit of each pseudo-plaintext sequence, and hash the pseudo-plaintext subsequences divided into multiple paths into the ciphertext space To form a sequence of ciphertext streams.
2. The encryption and decryption method according to claim 1, characterized in that it further comprises the following steps for decryption:

   S500) Obtain a ciphertext stream sequence, and use the same non-linear feedback function and the bit transformation Boolean function to preprocess a predetermined seed key to form a key stream sequence;

   S600) According to the inverse hash mapping rule that depends on the key stream sequence, calculate the hash address corresponding to the binary bit of each ciphertext sequence, and map the ciphertext sequence hash to the plaintext storage space to form a multi-path pseudo Plaintext subsequence;

   S700) Combine multiple pseudo-plaintext subsequences to form a pseudo-plaintext sequence;

   S800) Changing the bit value of the pseudo-plaintext sequence according to the bit transformation Boolean function based on the key stream sequence to form the plaintext sequence.
3. The encryption and decryption method according to claim 1 or 2, wherein the step S100 further comprises the following sub-steps:

   S101) Input the seed key to the nonlinear feedback function to generate the first output sequence;

   S102) Loop the first output sequence to fill the second output sequence formed into the key stream sequence space;

   S103) Input the second output sequence to transform the Boolean function in place to form a key stream sequence.
4. The encryption and decryption method according to claim 3, characterized in that, in the step S102, the starting position of the cyclic filling is any legal position in the first output sequence.
5. The encryption and decryption method according to claim 4, wherein the step S300 further comprises the following sub-steps:

   S301) The pseudo-plaintext sequence is decomposed into multiple pseudo-plaintext sub-sequences according to the true value bits and false value bits of the key stream sequence;

   S302) The multi-path pseudo-plaintext sub-sequence and the key stream sequence are respectively scanned bidirectionally to dynamically hash the multi-path pseudo-plaintext sub-sequence into the ciphertext space in a zippered manner.
6. The encryption and decryption method according to claim 1 or 2, wherein the plaintext sequence, the key stream sequence, and the ciphertext stream sequence all adopt the data structure of a circular queue, and the encryption and decryption is performed from the corresponding circular sequence. Start at any legal position in the queue.
7. The encryption and decryption method according to claim 1 or 2, wherein the bit transformation Boolean function is a bitwise inverse function according to a specific bit of the key stream sequence.
8. The encryption and decryption method according to claim 1 or 2, wherein the nonlinear feedback function is a feedback function with an algebraic order of 4 or more.
9. An encryption and decryption device based on zipper dynamic hashing and NLFSR, which is characterized in that it includes the following modules:

   The first key stream generation module is used to preprocess the seed key using a nonlinear feedback function and a bit transformation Boolean function to form a key stream sequence;

   The pseudo-plaintext generation module is used to change the bit value of the plaintext sequence according to the bit transformation Boolean function based on the key stream sequence to form a pseudo-plaintext sequence;

   The pseudo-plaintext division module is used to divide the pseudo-plaintext sequence into multiple pseudo-plaintext sub-sequences according to the key stream sequence;

   The first dynamic hash module is used to calculate the dynamic hash address corresponding to the binary bit of each pseudo-plaintext sequence according to the hash mapping rules that depend on the key stream sequence, and hash the pseudo-plaintext sub-sequences divided into multiple paths The columns are mapped into the ciphertext space to form a ciphertext stream sequence.
10. A computer-readable storage medium with computer instructions stored thereon, characterized in that the instructions implement the steps of the method according to any one of claims 1 to 8 when the instructions are executed by a processor.

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