Improved AES encryption method and system

Abstract

The invention discloses an improved AES (Advanced Encryption Standard) encryption method and system. The method comprises the following steps: carrying out logic mapping according to an initial key to generate m chaotic S boxes; x multiplication results of the m chaotic S boxes and column mixed matrix elements 02 and 03 are calculated respectively, and 2m column mixed lookup tables are formed; performing one round of initial change, (m-1) round of cyclic encryption and one round of final encryption on the to-be-encrypted data to obtain encryption information; wherein a chaos S box corresponding to the current round is used during byte substitution in the initial change and cyclic encryption steps; and replacing the X multiplication calculation operation in the column mixing step in the circular encryption step with the table lookup operation in the column mixing lookup table. According to the method, the column mixing step in the AES algorithm is optimized, and the original matrix multiplication operation which needs to consume a large number of operation resources is changed into the table look-up operation which is calculated and stored in advance, so that the operation time in an embedded system is greatly shortened, and the overall efficiency of the encryption process is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of Internet of Things data encryption, and in particular to an improved AES encryption method and system. Background Art

[0002] With the rapid development of IoT technology, the number of devices connected to the Internet is growing exponentially, and the security of data transmission between devices has become increasingly important. Especially at the IoT device level, devices are usually equipped with resource-limited embedded systems with low processor frequency and limited memory capacity, making the efficiency of data encryption algorithms a key issue.

[0003] Currently, commonly used data encryption algorithms include symmetric encryption algorithms such as AES and DES, and asymmetric encryption algorithms such as RSA and ECC. Among them, the AES algorithm is widely used in various embedded systems due to its efficient encryption performance, relatively low resource usage and strong security. However, the application of the AES algorithm at the IoT device layer still faces several challenges:

[0004] Computing resource consumption problem: Each step of the AES algorithm involves a large number of multiplication operations, which is not friendly to embedded systems with limited resources. Multiplication operations often consume more computing cycles, resulting in a decrease in overall encryption efficiency.

[0005] The problem of limited key space: The key expansion process of the AES algorithm relies on a fixed key expansion algorithm, and there is a large correlation between the keys of different rounds, which makes it possible for an attacker to obtain the keys of other rounds by inferring a key, thereby weakening the overall security of the system.

[0006] To solve these problems, the existing technology has proposed some improvement schemes. For example, chaotic sequences are generated by chaotic mapping and applied to the AES algorithm to improve its security. However, most of these improvement schemes fail to consider the resource limitations of embedded systems, increase the complexity of the algorithm, and do not effectively solve the problem of low execution efficiency of the AES algorithm in the resource-limited IoT device layer.

[0007] Therefore, how to improve the operating efficiency of the AES algorithm in resource-limited embedded systems while ensuring data transmission security has become an important research direction and technical challenge in the current field of IoT data encryption. Summary of the invention

[0008] In order to solve the above technical problems, the present invention provides an AES encryption method and system based on chaotic mapping improvement for resource limitations and security requirements of the IoT device layer. The technical solution of the present invention specifically includes:

[0009] Improve the AES encryption method, including the following steps:

[0010] m chaotic S-boxes generated after logical mapping based on the initial key;

[0011] Calculate the X-multiplication results of the m chaotic S-boxes and the column mixing matrix elements 02 and 03 respectively to form 2m column mixing lookup tables;

[0012] Perform 1 round of initial transformation, m-1 rounds of cyclic encryption and 1 round of final encryption on the encrypted data to obtain encrypted information;

[0013] Among them, the chaotic S box corresponding to the current round is used when performing byte substitution in the initial change and cyclic encryption steps; the X-multiplication calculation operation in the column mixing step in the cyclic encryption step is replaced by a table lookup operation in the column mixing lookup table.

[0014] Preferably, the method for generating m chaotic S-boxes after performing logical mapping according to the initial key comprises:

[0015] Obtain the initial key and use the logical mapping to iterate k times to obtain the encryption parameters;

[0016] Continue to iterate the encryption parameter using logical mapping, and quantize each iteration result into a binary sequence. After 16 iterations, convert the sequence into a hexadecimal value, and repeat the operation until a 16*16 chaotic S-box is formed; repeat this step to generate m chaotic S-boxes.

[0017] Preferably, the method of performing several iterations of the initial key using logical mapping includes: normalizing the initial key and retaining three decimal places as x; performing k rounds of chaotic mapping on x according to the following formula: k+1 =μx k (1-x k ), where μ is the chaos parameter.

[0018] Preferably, the method of quantizing each iteration result into a binary sequence includes: quantizing the iteration result into a binary sequence with 0.5 as a threshold.

[0019] The present invention also provides an improved AES encryption system comprising: a storage module and an encryption module;

[0020] The storage module includes an S-box storage unit and a column hybrid query table storage unit;

[0021] The S-box storage unit stores m chaotic S-boxes generated after logical mapping according to the initial key; the column mixing query table storage unit stores 2m column mixing query tables generated according to the X-multiplication results of the m chaotic S-boxes and the column mixing matrix elements 02 and 03;

[0022] The encryption module is connected to the storage module and is configured to receive data to be encrypted, and perform one round of initial change, m-1 rounds of cyclic encryption and one round of final encryption on the data to obtain encrypted information; wherein, when performing byte substitution in the initial change and cyclic encryption steps, a chaotic S-box corresponding to the current round is used; and the X-multiplication calculation operation in the column mixing step in the cyclic encryption step is replaced by a table lookup operation in the column mixing lookup table.

[0023] Preferably, the method for generating the m chaotic S-boxes includes:

[0024] Obtain the initial key and use the logical mapping to iterate k times to obtain the encryption parameters;

[0025] Continue to iterate the encryption parameter using logical mapping, and quantize each iteration result into a binary sequence. After 16 iterations, convert the sequence into a hexadecimal value, and repeat the operation until a 16*16 chaotic S-box is formed; repeat this step to generate m chaotic S-boxes.

[0026] Preferably, the method of performing several iterations of the initial key using logical mapping includes: normalizing the initial key and retaining three decimal places as x; performing k rounds of chaotic mapping on x according to the following formula: k+1 =μx k (1-x k ), where μ is the chaos parameter.

[0027] Preferably, the method of quantizing each iteration result into a binary sequence includes: quantizing the iteration result into a binary sequence with 0.5 as a threshold.

[0028] Beneficial Effects

[0029] Improved operational efficiency of encryption algorithms: The present invention optimizes the "column mixing" step in the AES algorithm, and replaces the matrix multiplication operation that originally required a large amount of computing resources with a pre-calculated and stored table lookup operation, thereby significantly reducing the computing time in the embedded system and improving the overall efficiency of the encryption process.

[0030] Expanded key space and enhanced security: The present invention introduces chaotic mapping technology, which increases the randomness and complexity of the key by generating multiple chaotic S-boxes and applying them to the byte substitution and key expansion steps of the AES algorithm, expands the key space, and reduces the correlation between keys in different rounds, thereby improving the anti-attack capability of the AES algorithm and enhancing the security of data transmission.

[0031] Reduced resource usage of embedded systems: Although the present invention generates multiple S-boxes and table lookup data through chaotic mapping, since these data only occupy a small amount of storage space (about 7.5KB), the impact on the storage resources of the embedded system is small. At the same time, by replacing complex calculations with table lookup, excessive consumption of embedded system computing resources is avoided, ensuring the lightweight and high efficiency of the algorithm.

[0032] Improved applicability and flexibility of the algorithm: By flexibly configuring the parameters and number of iterations of the chaotic map, the present invention can adjust the security and operational efficiency of the algorithm according to the security requirements and resource limitations of the specific application scenarios, so that it can be widely used in various IoT device layers, especially in scenarios with limited resources and high real-time requirements, and has good applicability. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 A schematic diagram of the improved AES encryption method flow in a preferred embodiment of the present invention;

[0034] Figure 2 The figure is a schematic diagram of the structure of an improved AES encryption system in a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solution and advantages of the present invention clearer, the present invention is further described below in conjunction with the accompanying drawings. In the description of the present invention, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside", "outside" and the like indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention.

[0036] Example 1

[0037] like Figure 1 As shown, this embodiment provides an improved AES encryption method, including the steps of:

[0038] S1, m chaotic S-boxes generated after logical mapping according to the initial key. S-box (Substitution Box) is an important component in symmetric encryption algorithms (such as AES), which plays the role of byte substitution and is a key nonlinear transformation component in the algorithm. Traditional S-boxes are implemented by a fixed table lookup method, while the chaotic S-box of the present application is an S-box generated based on chaos theory, which is used to replace the S-box in the traditional encryption algorithm, and is generated by chaotic mapping, thereby increasing the unpredictability and randomness of the S-box.

[0039] Logical mapping refers to a mathematical mapping function based on chaos theory, which is used to generate highly random and unpredictable sequences. Commonly used ones include Logistic mapping, Tent mapping, Henon mapping, etc. Its characteristic is that it is highly sensitive to initial conditions. Even if the initial value changes slightly, the final generated sequence will be completely different, which brings higher randomness and security to the encryption algorithm. Those skilled in the art can generate chaotic S-boxes according to the commonly used logical mapping method. In some preferred embodiments, a method for generating m chaotic S-boxes after logical mapping based on the initial key is provided, which specifically includes:

[0040] S11, obtain the initial key and perform k iterations of logical mapping to obtain encryption parameters. The number of iterations is set to make the system reach a fully chaotic state. In some preferred embodiments, K>=500. The specific operation steps are as follows: normalize the initial key and retain 3 decimal places as x; perform k rounds of chaotic mapping on x according to the following formula: x k+1 =μx k (1-x k ); where μ is the chaos parameter. The normalization method can make the value normalized to (0, 1) after logarithmic transformation. The value range of the chaos parameter μ is (3.57, 4], and the preferred μ = 4.

[0041] S12, continue to iterate the encryption parameters using logical mapping, and quantize each iteration result into a binary sequence, convert the sequence into a hexadecimal value after 16 iterations, and repeat the operation until a 16*16 chaotic S-box is formed; repeat this step to generate m chaotic S-boxes. The number of chaotic S-boxes generated is equivalent to the number of subsequent encryption rounds. The binarization of the iteration result can be designed by those skilled in the art according to a commonly used binary conversion method. In some preferred embodiments, a simple binarization method is provided, which specifically includes: quantizing the iteration result into a binary sequence with a threshold of 0.5.

[0042] S2. Calculate the X-multiplication results of the m chaotic S-boxes and the column mixing matrix elements 02 and 03 respectively to form 2m column mixing lookup tables.

[0043] Those skilled in the art will know that in the conventional AES encryption algorithm, when performing the column mixing step of the loop operation, it is necessary to replace the matrix with the given matrix after byte substitution and row shift. Left multiplication is performed, and the ordinary multiplication becomes X multiplication, that is, the x-time algorithm, specifically:

[0044] When the elements of a given matrix are 01, the multiplication of it with a number is still that number itself, which in the present invention is the single-use chaotic S-box itself.

[0045] When the element of the given matrix is ​​02, both numbers need to be converted to binary. If a7 is equal to 1, remove a7, shift one bit to the left, add 0 on the right, and then XOR 00011011; if a7 is equal to 0, remove a7 directly, shift one bit to the left, and add 0 on the right; the formula is as follows:

[0046]

[0047] Among them, a7a6a5a4a3a2a1a0 is the target element after conversion to binary.

[0048] When the element of the given matrix is ​​02, the calculation is more complicated. It is necessary to calculate the XOR of 02 and 01 respectively, then multiply them respectively, and finally XOR them again.

[0049] Obviously, such a calculation step consumes a lot of computing resources to perform multiplication and division operations, which increases the running time of the encryption algorithm. Therefore, the present invention considers replacing the X-multiplication calculation operation in the column mixing step in the cyclic encryption step with a table lookup operation in the column mixing lookup table. The specific implementation method includes:

[0050] First, the X multiplication results of the m chaotic S boxes and the column mixing matrix elements 02 and 03 are calculated respectively to form 2m column mixing query tables, which are stored in appropriate storage containers. When performing cyclic encryption later, the X multiplication calculation operation in the column mixing step is replaced by the table lookup operation in the column mixing query table, and then the table lookup result is XORed to obtain the column mixing matrix. In this regard, the present invention performs complex mathematical operations in advance before the encryption program is implemented, and then stores the operation results as a table. When it is needed later, the table lookup can be directly performed, thereby improving the multiplication operation that consumes more than 10 machine cycles to a simple table lookup operation, greatly reducing the running time of the algorithm, and only needs to store 20 additional tables to achieve it. Together with the previous black box, 30 16*16 operation tables are formed. The actual space occupied by this part of the table is about 7.5KB of storage space, which is basically negligible for today's embedded memory and will not cause the problem of increased time complexity in the plaintext encryption process.

[0051] S3, perform 1 round of initial transformation, m-1 rounds of cyclic encryption and 1 round of final encryption on the data to be encrypted to obtain encrypted information. This step is the same as the conventional AES encryption algorithm, and the present invention does not make further limitations and explanations on this.

[0052] It should be noted that, when performing byte substitution in the key expansion step, the present invention uses the chaotic S-box of the corresponding round to replace the fixed S-box in the prior art, thereby increasing the randomness and complexity of the key, expanding the key space, and reducing the correlation between keys of different rounds, thereby improving the anti-attack capability of the AES algorithm and enhancing the security of data transmission.

[0053] Example 2

[0054] In the field of the Internet of Things to which the present invention is applied, the device layer is usually composed of basic components such as an embedded CPU (central processing unit), a ROM memory, etc., wherein the data encryption process is mainly realized by the computing power of the embedded CPU, and the encryption key and the encryption result are stored and managed by the ROM memory. However, since the hardware resources of the Internet of Things device layer are generally limited, the main frequency of the embedded CPU is often low, and the memory capacity is relatively small. Therefore, in such a resource-constrained environment, the calculation speed and memory usage of the encryption algorithm become key technical bottlenecks.

[0055] Although the existing AES (Advanced Encryption Standard) algorithm performs well in terms of computational efficiency and security, it still has some shortcomings in specific application environments. On the one hand, the "column mixing" step of the AES algorithm involves a large number of multiplication and division operations, which consume a lot of computing resources and processing time in resource-constrained embedded systems, thereby affecting the response speed of the overall system. On the other hand, the key expansion process of the AES algorithm has a strong forward and backward dependency, and the correlation between keys is large, resulting in a limited key space. This limitation of the key space makes it possible for attackers to deduce all other keys by obtaining one key, thereby posing a threat to the security of the entire encryption system.

[0056] Therefore, in response to these problems, improving the execution efficiency of the AES algorithm in embedded systems and expanding the key space to enhance the security of the algorithm have become important issues that need to be urgently addressed in the field of data encryption technology at the IoT device layer.

[0057] like Figure 2 As shown, this embodiment provides an improved AES encryption system, which includes: a storage module and an encryption module.

[0058] The storage module includes an S-box storage unit and a column hybrid query table storage unit.

[0059] The S-box storage unit stores m chaotic S-boxes generated after logical mapping according to the initial key; the column mixed query table storage unit stores 2m column mixed query tables generated according to the X-multiplication results of the m chaotic S-boxes and the column mixed matrix elements 02 and 03. In the present invention, the chaotic S-box is pre-calculated and designed, and then stored in the S-box storage unit. It can be burned into the ROM memory of the chip when the main program is burned, and then the direct call in the subsequent encryption process is facilitated by specifying the storage address.

[0060] The chaotic S-box of the present application is an S-box generated based on chaos theory, which is used to replace the S-box in the traditional encryption algorithm. It is generated by chaotic mapping, thereby increasing the unpredictability and randomness of the S-box. Those skilled in the art can generate chaotic S-boxes according to the commonly used logical mapping method. In some preferred embodiments, a method for generating m chaotic S-boxes after logical mapping according to the initial key is provided, which specifically includes:

[0061] Obtain the initial key and perform k iterations of logical mapping to obtain encryption parameters. The number of iterations is set to allow the system to reach a fully chaotic state. In some preferred embodiments, K>=500. The specific operation steps are as follows: normalize the initial key and retain 3 decimal places as x; perform k rounds of chaotic mapping on x according to the following formula: x k+1 =μx k (1-x k ); where μ is the chaos parameter. The normalization method can make the value normalized to (0, 1) after logarithmic transformation. The value range of the chaos parameter μ is (3.57, 4], and the preferred μ = 4.

[0062] Continue to iterate the encryption parameters using logical mapping, and quantize each iteration result into a binary sequence. After 16 iterations, convert the sequence into a hexadecimal value, and repeat the operation until a 16*16 chaotic S-box is formed; repeat this step to generate m chaotic S-boxes. The number of chaotic S-boxes generated is equivalent to the number of subsequent encryption rounds. The binarization of the iteration result can be designed by those skilled in the art according to a commonly used binary conversion method. In some preferred embodiments, a simple binarization method is provided, which specifically includes: quantizing the iteration result into a binary sequence with a threshold of 0.5.

[0063] Those skilled in the art will know that in the conventional AES encryption algorithm, when performing the column mixing step of the loop operation, it is necessary to replace the matrix with the given matrix after byte substitution and row shift. Left multiplication is performed, and ordinary multiplication becomes X multiplication, that is, x-time algorithm. Obviously, such a calculation step needs to consume a lot of computing resources to perform multiplication and division operations, which increases the running time of the encryption algorithm. Therefore, the present invention considers replacing the X multiplication calculation operation in the column mixing step in the cyclic encryption step with a table lookup operation in the column mixing lookup table.

[0064] First, the X-multiplication results of the m chaotic S-boxes and the column mixing matrix elements 02 and 03 are calculated respectively to form 2m column mixing query tables, which are stored in the column mixing query table unit. When performing cyclic encryption later, the X-multiplication calculation operation in the column mixing step is replaced by the table lookup operation in the column mixing query table, and then the table lookup result is XORed to obtain the column mixing matrix. Similar to the setting of the chaotic S-box, the column mixing query table in the present invention is also pre-calculated and designed, and then stored in the column mixing query table storage unit. It can be burned into the ROM memory of the chip when the main program is burned, and then the direct call in the subsequent encryption process is facilitated by specifying the storage address.

[0065] In this regard, the present invention performs complex mathematical operations in advance before the encryption program is implemented, and then stores the operation results as a table. When needed later, the table can be directly looked up, thereby improving the multiplication operation that consumes more than 10 machine cycles into a simple table lookup operation, greatly reducing the running time of the algorithm. It only requires the storage of 30 additional tables to achieve it. The actual space occupied by these tables is about 7.5KB of storage space, which is basically negligible for today's embedded memory and will not cause the problem of increased time complexity in the plaintext encryption process.

[0066] The encryption module is connected to the storage module and is configured to receive data to be encrypted, and perform one round of initial change, m-1 rounds of cyclic encryption and one round of final encryption on the data to obtain encrypted information; wherein, when performing byte substitution in the initial change and cyclic encryption steps, a chaotic S-box corresponding to the current round is used; and the X-multiplication calculation operation in the column mixing step in the cyclic encryption step is replaced by a table lookup operation in the column mixing lookup table.

[0067] Example 3

[0068] This embodiment is developed on the basis of the above-mentioned embodiments 1 and 2, and this embodiment further demonstrates the present invention in conjunction with a specific case.

[0069] Get the initial key 2b7e151628aed2a6abf7158809cf4f3c, and express it in decimal as 57811460909138771071931939740208549692. Use logarithmic transformation to normalize the above decimal string to (0,1): 0.01*Lg57811460909138771071931939740208549692=0.3776201, retain 3 decimal places and record it as x: x=0.378. Perform k rounds of chaotic mapping on x according to the following formula: x k+1 =μx k (1-x k ); where k = 500 and μ = 4. After 500 iterations, x = 0.583.

[0070] Continue to iterate, using 0.5 as the threshold to quantize the iterated value into a binary sequence of 0 and 1. After every 16 iterations, the sequence is converted into a hexadecimal number, and a 16*16 chaotic S-box is formed from top to bottom and from left to right. Repeat this step to generate 10 chaotic S-boxes. The following provides an example of the chaotic S-box generated in the second round. Similarly, the subsequent encryption operation is also the second round of encryption steps:

[0071]

[0072] Get column mixing matrix It can be seen from the matrix that the coefficients of A1 are only 1, 2, and 3. Based on this characteristic, the present invention calculates and stores the X-multiplication results of m chaotic S-boxes and column mixing matrix elements 02 and 03 in advance. The table with a coefficient of 1 is the S-box. Since a total of 10 chaotic S-boxes are used in the round operation, 20 tables need to be stored for the column mixing query table of the column mixing step. The column mixing query table corresponding to the chaotic S-box is as follows:

[0073] Multiply the columns by 02 and mix the query table:

[0074]

[0075] Multiply the columns by 03 and mix the query table:

[0076]

[0077] Get the data to be encrypted 3243f6a8885a308d313198a2e0370734. It should be understood that the data to be encrypted here is the first set of plaintext obtained after processing according to the requirements of the AES encryption algorithm, rather than the entire data to be encrypted. Arrange it in a matrix form:

[0078]

[0079] Make the initial change, that is, XOR with the initial key:

[0080]

[0081] Perform byte substitution and row shifting:

[0082]

[0083] Perform column mixing and replace the step of left multiplication of the matrix in the original column mixing with direct table lookup. The final result is as follows:

[0084]

[0085] The subsequent steps are the same as the existing AES algorithm, including 8 rounds of cyclic encryption and 1 round of final encryption to obtain encrypted information. Due to space constraints, the running results are not given here.

[0086] The above shows and describes the basic principles, main features and advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. Improved AES encryption method, characterized in that: Includes steps: m chaotic S-boxes generated after logical mapping based on the initial key; Calculate the X-multiplication results of the m chaotic S-boxes and the column mixing matrix elements 02 and 03 respectively to form 2m column mixing lookup tables; Perform 1 round of initial transformation, m-1 rounds of cyclic encryption and 1 round of final encryption on the encrypted data to obtain encrypted information; Among them, the chaotic S box corresponding to the current round is used when performing byte substitution in the initial change and cyclic encryption steps; the X-multiplication calculation operation in the column mixing step in the cyclic encryption step is replaced by a table lookup operation in the column mixing lookup table.

2. The improved AES encryption method as claimed in claim 1, characterized in that: The method for generating m chaotic S-boxes after performing logical mapping according to the initial key comprises: Obtain the initial key and use the logical mapping to iterate k times to obtain the encryption parameters; Continue to iterate the encryption parameter using logical mapping, and quantize each iteration result into a binary sequence. After 16 iterations, convert the sequence into a hexadecimal value, and repeat the operation until a 16*16 chaotic S-box is formed; repeat this step to generate m chaotic S-boxes.

3. The improved AES encryption method as claimed in claim 2, characterized in that: The method of performing several iterations of the initial key using logical mapping includes: normalizing the initial key and retaining three decimal places as x; performing k rounds of chaotic mapping on x according to the following formula: k+1 =μx k (1-x k ), where μ is the chaos parameter.

4. The improved AES encryption method as claimed in claim 2, characterized in that: The method of quantizing each iteration result into a binary sequence includes: quantizing the iteration result into a binary sequence with 0.5 as a threshold.

5. Improved AES encryption system, characterized in that: include: Storage module and encryption module; The storage module includes an S-box storage unit and a column hybrid query table storage unit; The S-box storage unit stores m chaotic S-boxes generated after logical mapping according to the initial key; the column mixing query table storage unit stores 2m column mixing query tables generated according to the X-multiplication results of the m chaotic S-boxes and the column mixing matrix elements 02 and 03; The encryption module is connected to the storage module and is configured to receive the data to be encrypted, and perform 1 round of initial change, m-1 rounds of cyclic encryption and 1 round of final encryption on the data to obtain encrypted information; Among them, the chaotic S-box corresponding to the current round is used when performing byte substitution in the initial change and cyclic encryption steps; The X-multiplication operation in the column mixing step in the cyclic encryption step is replaced by a table lookup operation in the column mixing lookup table.

6. The improved AES encryption system as claimed in claim 5, characterized in that: The method for generating the m chaotic S-boxes comprises: Obtain the initial key and use the logical mapping to iterate k times to obtain the encryption parameters; Continue to iterate the encryption parameter using logical mapping, and quantize each iteration result into a binary sequence. After 16 iterations, convert the sequence into a hexadecimal value, and repeat the operation until a 16*16 chaotic S-box is formed; repeat this step to generate m chaotic S-boxes.

7. The improved AES encryption system as claimed in claim 6, characterized in that: The method of performing several iterations of the initial key by using logical mapping comprises: normalizing the initial key and retaining three decimal places as x; performing k rounds of chaotic mapping on x according to the following formula: k+1 =μx k (1-x k ), where μ is the chaos parameter.

8. The improved AES encryption system as claimed in claim 6, characterized in that: The method of quantizing each iteration result into a binary sequence includes: quantizing the iteration result into a binary sequence with 0.5 as a threshold.

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