A multi-key image encryption method based on five-dimensional conservative hyperchaotic system

Abstract

The present invention provides a multi-key image encryption method based on a five-dimensional conservative hyperchaotic system, comprising: constructing a five-dimensional conservative hyperchaotic system; generating a chaotic pseudo-random sequence for the first scrambling based on a plaintext image; scrambling the plaintext image according to the chaotic pseudo-random sequence for the first scrambling; generating a pseudo-random sequence for forward diffusion and a pseudo-random sequence for reverse diffusion based on the first scrambling graph; diffusing the first scrambled image according to the pseudo-random sequence for forward diffusion and the pseudo-random sequence for reverse diffusion; generating a chaotic pseudo-random sequence for the second scrambling based on the diffusion graph; scrambling the diffusion graph according to the chaotic pseudo-random sequence for the second scrambling to generate a ciphertext image. The present invention designs a multi-key image encryption algorithm using a wide initial value range of the system, solves the key leakage problem and the chaotic sequence utilization problem, and thus improves the security of image encryption.

Description

Technical Field

[0001] The present invention relates to the field of image encryption technology, and in particular to a multi-key image encryption method based on a five-dimensional conservative hyperchaotic system. Background Art

[0002] Chaotic behavior is very suitable for application in the field of encryption because of its initial value sensitivity, ergodicity and unpredictability. With the popularization of mobile networks, the dissemination of Internet content with images as information carriers has developed rapidly, which inevitably brings about the problem of information leakage. Image encryption algorithms based on chaos theory have attracted the attention of more and more scholars and have become a hot topic in image protection technology.

[0003] The chaotic system currently commonly used in image encryption is a dissipative chaotic system, but it has attractors that can be easily reconstructed by attackers, resulting in the encryption algorithm being cracked.

[0004] In recent years, some scholars have used conservative chaos to replace dissipative chaos. Conservative chaos is integer-dimensional, has no attractors, has better ergodicity, cannot be reconstructed, has better security, and is more suitable for applications in image encryption and confidential communication. At present, the mainstream image encryption algorithm is mainly based on improved scrambling and diffusion methods. There are few image encryption schemes that improve the key according to the one-time one-key principle, and most of them are single-key or multiple encryption steps share a key. However, due to the encryption method of using a single key or multiple encryption steps sharing a key, there are certain security risks and it is easy to crack. For example, the Chinese invention patent with announcement number CN109803063A discloses "an image encryption method based on a five-dimensional hyperchaotic system", which generates a chaotic sequence through a five-dimensional dissipative chaotic system and uses four random sequences therein to encrypt the image. This method only uses one set of keys. This encryption method has the problem that the key is single and easy to leak. At the same time, the chaotic sequence is not fully utilized, and the advantages of the chaotic system in the field of image encryption are not fully utilized, resulting in a waste of resources. Summary of the invention

[0005] The present invention provides a multi-key image encryption method based on a five-dimensional conservative hyperchaotic system. The multi-key image encryption algorithm is designed by utilizing the wide initial value range of the system, aiming to solve the key leakage problem and the chaotic sequence utilization problem, so as to improve the security of image encryption and provide new ideas for the application of conservative chaos in the encryption field.

[0006] The technical means adopted by the present invention are as follows:

[0007] The present invention discloses a multi-key image encryption method based on a five-dimensional conservative hyperchaotic system, comprising the following steps:

[0008] Construct a five-dimensional conservative hyperchaotic system;

[0009] Acquire a plaintext image to be encrypted, calculate a first hash value based on the plaintext image, and generate a first key sequence based on the first hash value;

[0010] Obtaining the missing initial value of the five-dimensional conservative hyperchaotic system as the first initial value through the first key sequence; bringing the first initial value into the five-dimensional conservative hyperchaotic system for iterative calculation, thereby generating a chaotic pseudo-random sequence used for the first scrambling;

[0011] Scramble the plaintext image according to the chaotic pseudo-random sequence used in the first scrambling to generate the first scrambled image;

[0012] Calculate a second Hash value based on the first scrambled graph, and generate a second key sequence based on the second Hash value;

[0013] The missing initial value of the five-dimensional conservative hyperchaotic system is obtained as the second initial value through the second key sequence; the second initial value is brought into the five-dimensional conservative hyperchaotic system for iterative operation, thereby generating a pseudo-random sequence used for forward diffusion and a pseudo-random sequence used for reverse diffusion;

[0014] Diffusion of the first scrambled image is performed according to the pseudo-random sequence used for the forward diffusion and the pseudo-random sequence used for the reverse diffusion to generate a diffusion map;

[0015] Calculate a third Hash value based on the diffusion map, and generate a third key sequence based on the third Hash value;

[0016] Obtaining the missing initial value of the five-dimensional conservative hyperchaotic system as the third initial value through the third key sequence; bringing the third initial value into the five-dimensional conservative hyperchaotic system for iterative calculation, thereby generating a chaotic pseudo-random sequence used for the second scrambling;

[0017] The diffusion map is scrambled according to the chaotic pseudo-random sequence used in the second scrambling to generate a ciphertext image.

[0018] The present invention also discloses a multi-key image encryption device based on a five-dimensional conservative hyperchaotic system, comprising:

[0019] Chaotic system building module, which is used to build a five-dimensional conservative hyperchaotic system;

[0020] A first chaotic pseudo-random sequence generation module is used to obtain a plaintext image to be encrypted, calculate a first hash value based on the plaintext image, and generate a first key sequence based on the first hash value; obtain the missing initial value of the five-dimensional conservative hyperchaotic system as the first initial value through the first key sequence; bring the first initial value into the five-dimensional conservative hyperchaotic system for iterative calculation, thereby generating a chaotic pseudo-random sequence used for the first scrambling;

[0021] A first scrambling module, which is used to scramble the plaintext image according to the chaotic pseudo-random sequence used for the first scrambling to generate a first scrambling graph;

[0022] A second chaotic pseudo-random sequence generation module is used to calculate a second hash value based on the first scrambled graph, and generate a second key sequence based on the second hash value; obtain the missing initial value of the five-dimensional conservative hyperchaotic system as the second initial value through the second key sequence; bring the second initial value into the five-dimensional conservative hyperchaotic system for iterative operation, thereby generating a pseudo-random sequence used for forward diffusion and a pseudo-random sequence used for reverse diffusion;

[0023] A diffusion module, which is used to diffuse the first scrambled image according to the pseudo-random sequence used for forward diffusion and the pseudo-random sequence used for reverse diffusion to generate a diffusion map;

[0024] A third chaotic pseudo-random sequence generation module is used to calculate a third hash value based on the diffusion map, generate a third key sequence based on the third hash value; obtain the missing initial value of the five-dimensional conservative hyperchaotic system as a third initial value through the third key sequence; bring the third initial value into the five-dimensional conservative hyperchaotic system for iterative calculation, thereby generating a chaotic pseudo-random sequence used for the second scrambling;

[0025] The second scrambling module is used to scramble the diffusion image according to the chaotic pseudo-random sequence used in the second scrambling to generate a ciphertext image.

[0026] The present invention also discloses a storage medium, which includes a stored program, wherein when the program is run, any of the multi-key image encryption methods based on a five-dimensional conservative hyperchaotic system described above is executed.

[0027] Compared with the prior art, the present invention has the following advantages:

[0028] 1. The present invention realizes the close correlation between multiple keys and plaintext images based on a five-dimensional conservative hyperchaotic system, can obtain a sufficiently large key space, and at the same time fully utilizes the chaotic sequence, and can also effectively resist known plaintext attacks.

[0029] 2. The algorithm designed by the present invention only needs to improve the key, and does not require complex scrambling and diffusion methods to ensure encryption performance.

[0030] Based on the above reasons, the present invention can be widely promoted in the fields of encryption communication technology and the like. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0032] Figure 1 This is a flow chart of the multi-key image encryption method based on a five-dimensional conservative hyperchaotic system of the present invention.

[0033] Figure 2 Dynamical map of a conservative hyperchaotic system, where (a) represents the maximum Lyapunov exponent and (b) represents the sum of the Lyapunov exponents.

[0034] Figure 3 is the spectral entropy complexity of the conservative hyperchaotic system.

[0035] Figure 4 is the phase diagram of the conservative hyperchaotic system in the x1-x4 plane, where (a) represents x 20 =10,x 40 =10(b) means x 20 =45,x 40 =35, (c) represents x 20 =80,x 40 =60.

[0036] Figure 5 This is the overall process of the multi-key image encryption algorithm in the embodiment.

[0037] Figure 6 , which is the rule for index scrambling in the embodiment.

[0038] Figure 7 1 is a simulation result of the encryption algorithm in the embodiment, where (a) represents the original image, (b) represents the ciphertext image, and (c) represents the decrypted image.

[0039] Figure 8 are histograms in the embodiment, where (a) represents the histogram of the original image and (b) represents the histogram of the ciphertext image.

[0040] Fig. 9 ] are related situations of the images in the embodiment, where (a) represents the horizontal direction of the original image, (b) represents the vertical direction of the original image, (c) represents the diagonal direction of the original image, (d) represents the horizontal direction of the ciphertext image, (e) represents the vertical direction of the ciphertext image, and (f) represents the diagonal direction of the ciphertext image. DETAILED DESCRIPTION

[0041] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0042] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0043] like Figure 1 As shown, the present invention discloses a multi-key image encryption method based on a five-dimensional conservative hyperchaotic system, comprising the following steps:

[0044] S1. Construct a five-dimensional conservative hyperchaotic system.

[0045] The present invention preferably constructs a five-dimensional conservative hyperchaotic system with a wide initial value range and good performance. (The system construction method refers to Zhang Z, Huang LA new 5D Hamiltonian conservative hyperchaotic system with four center type equilibrium points, wide range and coexisting hyperchaotic orbits [J]. Nonlinear Dynamics, 2022, 108 (1): 637-652.) The system model is as follows:

[0046]

[0047] In this system, the parameters are set to (Π1, Π2, Π3, Π4, Π5, a) = (9, 2, 6, 4, 1, 0.8), and the initial value is (0.5, x 20 ,0.1,x 40 ,0.5), where x 20∈[0,80],x 40 ∈[0,60]. The dynamic map drawn based on the above five-dimensional conservative hyperchaotic system is as follows Figure 2 As shown, we can see that the maximum Lyapunov exponent is always greater than 0, and the values ​​of the Lyapunov exponent and are approximately equal to 0, which proves that the system is a conservative hyperchaotic system in a wide range of initial values. Figure 3 is the corresponding spectral entropy complexity. The larger the value, the higher the complexity. After comprehensive consideration, the wide initial value range is finally selected as x 20 ∈[10,80],x 40 ∈[10,60]. Figure 4 These are the phase diagrams corresponding to several special initial values. It can be seen from the diagram that there is no attractor in the system and the ergodicity is good.

[0048] The encryption strategy is the common "scramble-diffusion-scramble". The present invention also performs encryption based on this strategy, but uses different keys in different encryption processes. This can not only obtain a sufficiently large key space, but also make full use of the chaotic sequence and resist known plaintext attacks.

[0049] S2. Obtain a plaintext image to be encrypted, calculate a first hash value based on the plaintext image, and generate a first key sequence based on the first hash value. Obtain the missing initial value of the five-dimensional conservative hyperchaotic system through the first key sequence as the first initial value. Bring the first initial value into the five-dimensional conservative hyperchaotic system for iterative calculation, thereby generating a chaotic pseudo-random sequence used for the first scrambling.

[0050] Specifically, the generation of the first key sequence includes the following steps:

[0051] S211. Obtain a grayscale image of size M×N as a plaintext image P, and extract a row matrix, a column matrix, and a diagonal matrix from P.

[0052] S212: Calculate a first primary hash value H1 using SHA-512 based on the row matrix, column matrix and diagonal matrix, and calculate a first binary hash value HH1 using SHA-384 based on the first primary hash value H1. Calculate according to the following formula:

[0053]

[0054] S213, group the first hash values ​​and perform decimal conversion to generate a first key sequence. Divide the hash value HH1 into 24 groups, each with 16 bits, and then convert it into a decimal number as the first group key sequence K1, K1 = (k1, k2, k3, k4, ..., k 21 ,k 22 ,k 23 ,k 24).

[0055] Furthermore, the two missing initial values ​​of the conservative chaotic system are generated by equation (3):

[0056]

[0057] Furthermore, the initial value x′ 20 and x′ 40 Substitute the set initial value into formula (1), use the Runge-Kutta algorithm, iterate the chaotic system 1000+M×N times, and obtain five groups of chaotic pseudo-random sequences X′1, X′2, X′3, X′4, and X′5. Considering the transient efficiency, the first 1000 numbers of each group of sequences are removed. Then select the first and third groups of sequences, generate the chaotic pseudo-random sequence used for the first scrambling through formula (4), and convert the sequence into an integer type pseudo-random sequence S1 as the chaotic pseudo-random sequence used for the first scrambling:

[0058]

[0059] S3. Scramble the plaintext image according to the chaotic pseudo-random sequence used in the first scrambling to generate a first scrambled image.

[0060] In this embodiment, the pseudo-random sequence S1 is sorted in ascending order by means of the sort function to obtain an index sequence, the position of each element of the index sequence is marked, and the subscript is saved in the sequence I1. Figure 6 is the index rule. Then, the plaintext image P is scrambled without repetition using the sequence I1 as shown in formula (5), and then the scrambled matrix Ps1 is reconstructed to obtain the image Ps′1 as the first scrambled image.

[0061]

[0062] in,

[0063] S4. Calculate a second hash value based on the first scrambled graph, and generate a second key sequence based on the second hash value. Obtain the missing initial value of the five-dimensional conservative hyperchaotic system through the second key sequence as the second initial value; bring the second initial value into the five-dimensional conservative hyperchaotic system for iterative operation, thereby generating a pseudo-random sequence used for forward diffusion and a pseudo-random sequence used for reverse diffusion.

[0064] In this embodiment, the second set of keys is to extract the row matrix, column matrix and diagonal matrix from the image after the first scrambling, calculate the second primary hash value H2 using SHA-384, and then use SHA-256 to obtain a binary second hash value HH2 with a length of 256 bits:

[0065]

[0066] The second hash value HH2 is divided into 16 groups, each with 16 bits, and then converted into a decimal number as the second key sequence K2, K2 = (k1, k2, k3, k4, ..., k 13 ,k 14 ,k 15 ,k 16 ).

[0067] Furthermore, the two missing initial values ​​of the conservative chaotic system are generated by equation (4).

[0068]

[0069] Furthermore, the initial value x″ 20 and x″ 40 Substitute the set initial value into formula (1) and still use the Runge-Kutta algorithm to iterate the chaotic system 1000+2×M×N times to obtain five groups of chaotic pseudo-random sequences X″1, X″2, X″3, X″4 and X″5. Considering the transient efficiency, the first 1000 numbers of each group of sequences are removed. Then select the second and fourth groups of sequences, generate a new chaotic pseudo-random sequence S2 through formula (8), and process the sequence to generate the pseudo-random sequence S used for forward diffusion. 21 and the pseudo-random sequence S used for reverse diffusion 22 .

[0070]

[0071] Here, pow2(16) means to raise 2 to the 16th power.

[0072] S5. Diffusion of the first scrambled image is performed according to the pseudo-random sequence used for forward diffusion and the pseudo-random sequence used for reverse diffusion to generate a diffusion map.

[0073] Specifically, the image Ps′1 obtained after the first scrambling is expanded into a one-dimensional vector Ps2, and then diffusion based on XOR operation is performed. The algorithm of forward diffusion is Where Temp is a password vector of length M×N, Temp(0)=0, and i ranges from 1 to MN. The algorithm for reverse diffusion is Wherein Ps′2(MN+1)=0, i ranges from MN to 1. The obtained matrix Ps′2 is reconstructed to obtain the diffused image Ps″2.

[0074] S6. Calculate a third hash value based on the diffusion map, and generate a third key sequence based on the third hash value; obtain the missing initial value of the five-dimensional conservative hyperchaotic system as the third initial value through the third key sequence; bring the third initial value into the five-dimensional conservative hyperchaotic system for iterative calculation, so as to generate a chaotic pseudo-random sequence used for the second scrambling.

[0075] In this embodiment, the third key sequence third group of keys is to extract the row matrix, column matrix and diagonal matrix from the diffused image, calculate the third primary hash value H3 using SHA-256, and then use SHA-256 to obtain the third binary hash value HH3 with a length of 256 bits:

[0076]

[0077] The third hash value HH3 is divided into 32 groups, each with 8 bits, and then converted into a decimal number as the third group key sequence K3, K3 = (k1, k2, k3, k4, ..., k 29 ,k 30 ,k 31 ,k 32 ), and the two missing initial values ​​of the conservative chaotic system are generated through equation (5).

[0078]

[0079] Furthermore, the initial value x″′ 20 and x″′ 40 Substitute the set initial value into formula (1) and still use the Runge-Kutta algorithm to iterate the chaotic system 1000+M×N times to obtain five groups of chaotic pseudo-random sequences X″′1, X″′2, X″′3, X″′4, and X″′5. Considering the transient efficiency, the first 1000 numbers of each group of sequences are removed. Then select the third and fifth groups of sequences and generate a new chaotic pseudo-random sequence S3 through formula (11):

[0080]

[0081] S7. Scramble the diffusion map according to the chaotic pseudo-random sequence used in the second scrambling to generate a ciphertext image C.

[0082] The second scrambling in this embodiment is performed in the same principle as the first scrambling. The pseudo-random sequence S3 is sorted in ascending order by means of the sort function to obtain an index sequence, and the position of each element of the index sequence is marked, and the subscript is saved in the sequence I2. Then, the diffusion image Ps″2 is scrambled without repetition using the sequence I2, and then the scrambled matrix is ​​reconstructed to obtain the ciphertext image C.

[0083] The embodiment of the present invention further discloses a multi-key image decryption method which is an inverse process of the multi-key image encryption method based on the five-dimensional conservative hyperchaotic system, which will not be described in detail here.

[0084] The scheme and effect of the present invention are further described below through a specific application example.

[0085] like Figure 7 As shown in FIG. 1 , this embodiment performs multi-key encryption based on a five-dimensional conservative hyperchaotic system on a Baboon image of size 512×512, where (a) represents the original image, (b) represents the ciphertext image, and (c) represents the decrypted image. Figure 7-9 The performance of this method is analyzed as follows:

[0086] (1) A brute force attack will attempt to thoroughly search for all keys to crack the password. In theory, it is only a matter of time before the crack is completed. To combat brute force attacks, the key space must be large enough, at least 2 100 The encryption algorithm designed in this paper uses three sets of keys with a total of 6 initial values, all with an accuracy of 10 -14 , so we can get the key space of our scheme as:

[0087] (50×10 14 ×70×10 14 ) 3 =4.2875×10 94 >2 284 >>2 100 ,

[0088] It is enough to resist various brute force attacks, proving that this algorithm is secure enough.

[0089] (2) The histogram can intuitively reflect the distribution of image pixel values. Figure 8 The plaintext histogram and ciphertext histogram of the grayscale image are displayed. It can be seen that the ciphertext histogram is evenly distributed and significantly different from the plaintext histogram, indicating that this encryption algorithm has good statistical attack resistance capabilities.

[0090] (3) The correlation between adjacent pixels is also an important statistical feature of the image. In order to compare the correlation characteristics of the plaintext image and the ciphertext image, this paper analyzes the correlation between adjacent pixels in the horizontal, vertical and diagonal directions. Usually, there is a strong correlation between adjacent pixels in the plaintext image, while there should be no correlation between adjacent pixels in the ciphertext image. We select 2000 pairs of adjacent pixels from the target image and calculate the correlation using formula (12). (x i ,y i), (i=1,2,…,N) are the pixel values ​​of two adjacent pixels in the image, E(x) and D(x) represent the mean and variance of the variable x, respectively. Fig. 9 It is the correlation of the Baboon graph in all directions. The adjacent pixel pairs of the plaintext image are concentrated near y=x, indicating that the correlation of the plaintext image in all directions is very high, while the adjacent pixel pairs of the ciphertext image are evenly distributed irregularly, indicating that the correlation of the ciphertext image is very small. This algorithm can resist statistical attacks.

[0091]

[0092] (4) Information entropy reflects the uncertainty of image information. The larger the entropy value, the stronger the randomness and the less information leakage. Information entropy can be calculated by formula (13), where L is the number of gray levels of the image, and p(i) represents the probability of gray value i appearing. For an image with a gray level of 256, the theoretical value of information entropy is 8. The information entropy of the encrypted Baboon is 7.9994, which is close to 8. Therefore, the encryption algorithm in this paper has good security.

[0093]

[0094] (5) Attackers usually make small changes to the plaintext image, and then observe the corresponding changes in the ciphertext image, trying to find the relationship between the two ciphertext images through comparison. This is a differential attack. A good encryption algorithm should be able to achieve a very large change in the ciphertext image when a small change in the plaintext image occurs. Two important indicators are usually used to measure the ability of an encryption algorithm to resist differential attacks, namely the number of pixels change rate (NPCR) and the unified average change intensity (UACI). The corresponding calculation formula is as follows:

[0095]

[0096] P1 and P2 are two ciphertext images obtained by encrypting two plaintext images with very small pixel value differences using the same key, and the size is M × N. If P1(i, j) = P2(i, j), then D(i, j) = 0, otherwise D(i, j) = 1.

[0097] The ideal values ​​of NPCR and UACI are 99.6094% and 33.4635% respectively. The present invention only changes one pixel value of the Baboon image and calculates the values ​​of NPCR and UACI, which are 99.62% and 33.53% respectively, both of which are close to the ideal values. Therefore, the new algorithm can resist differential attacks well.

[0098] In summary, the image encryption algorithm mentioned in the present invention has good security.

[0099] The present invention also discloses a multi-key image encryption device based on a five-dimensional conservative hyperchaotic system, comprising:

[0100] Chaotic system building module, which is used to build a five-dimensional conservative hyperchaotic system;

[0101] A first chaotic pseudo-random sequence generation module is used to obtain a plaintext image to be encrypted, calculate a first hash value based on the plaintext image, and generate a first key sequence based on the first hash value; obtain the missing initial value of the five-dimensional conservative hyperchaotic system as the first initial value through the first key sequence; bring the first initial value into the five-dimensional conservative hyperchaotic system for iterative calculation, thereby generating a chaotic pseudo-random sequence used for the first scrambling;

[0102] A first scrambling module, which is used to scramble the plaintext image according to the chaotic pseudo-random sequence used for the first scrambling to generate a first scrambling graph;

[0103] A second chaotic pseudo-random sequence generation module is used to calculate a second hash value based on the first scrambled graph, and generate a second key sequence based on the second hash value; obtain the missing initial value of the five-dimensional conservative hyperchaotic system as the second initial value through the second key sequence; bring the second initial value into the five-dimensional conservative hyperchaotic system for iterative operation, thereby generating a pseudo-random sequence used for forward diffusion and a pseudo-random sequence used for reverse diffusion;

[0104] A diffusion module, which is used to diffuse the first scrambled image according to the pseudo-random sequence used for forward diffusion and the pseudo-random sequence used for reverse diffusion to generate a diffusion map;

[0105] A third chaotic pseudo-random sequence generation module is used to calculate a third hash value based on the diffusion map, generate a third key sequence based on the third hash value; obtain the missing initial value of the five-dimensional conservative hyperchaotic system as a third initial value through the third key sequence; bring the third initial value into the five-dimensional conservative hyperchaotic system for iterative calculation, thereby generating a chaotic pseudo-random sequence used for the second scrambling;

[0106] The second scrambling module is used to scramble the diffusion image according to the chaotic pseudo-random sequence used in the second scrambling to generate a ciphertext image.

[0107] For the multi-key image encryption device based on a five-dimensional conservative hyperchaotic system in the embodiment of the present invention, since it corresponds to the multi-key image encryption method based on a five-dimensional conservative hyperchaotic system in the above embodiment, the description is relatively simple. For relevant similarities, please refer to the description of the multi-key image encryption method based on a five-dimensional conservative hyperchaotic system in the above embodiment, which will not be described in detail here.

[0108] The present invention also discloses a storage medium, which includes a stored program, wherein when the program is run, any of the multi-key image encryption methods based on a five-dimensional conservative hyperchaotic system described above is executed.

[0109] The serial numbers of the above embodiments of the present invention are only for description and do not represent the advantages or disadvantages of the embodiments.

[0110] In the above embodiments of the present invention, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0111] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. Among them, the device embodiments described above are only schematic. For example, the division of the units can be a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of units or modules, which can be electrical or other forms.

[0112] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple units. Some or all of the units may be selected according to actual needs to achieve the purpose of the present embodiment.

[0113] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0114] 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 technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions for a computer device (which can be a personal computer, a server or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), mobile hard disk, magnetic disk or optical disk and other media that can store program codes.

[0115] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A multi-key image encryption method based on a five-dimensional conservative hyperchaotic system, characterized in that: The following steps are involved: Construct a five-dimensional conservative hyperchaotic system; Acquire a plaintext image to be encrypted, calculate a first hash value based on the plaintext image, and generate a first key sequence based on the first hash value; Obtaining the missing initial value of the five-dimensional conservative hyperchaotic system as the first initial value through the first key sequence; Bringing the first initial value into a five-dimensional conservative hyperchaotic system for iterative calculation, thereby generating a chaotic pseudo-random sequence used for the first scrambling; Scramble the plaintext image according to the chaotic pseudo-random sequence used in the first scrambling to generate the first scrambled image; Calculate a second Hash value based on the first scrambled graph, and generate a second key sequence based on the second Hash value; Obtaining the missing initial value of the five-dimensional conservative hyperchaotic system as the second initial value through the second key sequence; Bringing the second initial value into the five-dimensional conservative hyperchaotic system for iterative operation, thereby generating a pseudo-random sequence used for forward diffusion and a pseudo-random sequence used for reverse diffusion; Diffusion of the first scrambled image is performed according to the pseudo-random sequence used for the forward diffusion and the pseudo-random sequence used for the reverse diffusion to generate a diffusion map; Calculate a third Hash value based on the diffusion map, and generate a third key sequence based on the third Hash value; Obtaining the missing initial value of the five-dimensional conservative hyperchaotic system as the third initial value through the third key sequence; bringing the third initial value into the five-dimensional conservative hyperchaotic system for iterative calculation, thereby generating a chaotic pseudo-random sequence used for the second scrambling; The diffusion map is scrambled according to the chaotic pseudo-random sequence used in the second scrambling to generate a ciphertext image.

2. According to claim 1, a multi-key image encryption method based on a five-dimensional conservative hyperchaotic system is characterized in that: The five-dimensional conservative hyperchaotic system model is as follows: The parameters are set to (Π1, Π2, Π3, Π4, Π5, a) = (9, 2, 6, 4, 1, 0.8), and the initial value is (0.5, x 20 ,0.1,x 40 ,0.5), where x 20 ∈[10,80],x 40 ∈[10,60].

3. According to claim 1, a multi-key image encryption method based on a five-dimensional conservative hyperchaotic system is characterized in that: Calculating a first Hash value based on the plaintext image, and generating a first key sequence based on the first Hash value, comprising: Obtaining a row matrix, a column matrix and a diagonal matrix of the plaintext image; Calculate a first primary hash value using SHA-512 based on the row matrix, the column matrix, and the diagonal matrix; Based on the first primary hash value, a first binary hash value is calculated using SHA-384; The first hash values ​​are grouped and converted into decimal form to generate a first key sequence.

4. According to claim 3, a multi-key image encryption method based on a five-dimensional conservative hyperchaotic system is characterized in that: The first initial value is brought into the five-dimensional conservative hyperchaotic system for iterative operation, thereby generating a chaotic pseudo-random sequence used for the first scrambling, including: Bringing the first initial value into the five-dimensional conservative hyperchaotic system and iterating it for a preset number of times to generate five groups of chaotic pseudo-random sequences; A chaotic pseudo-random sequence used for the first scrambling is generated based on the first and third groups of chaotic pseudo-random sequences.

5. The multi-key image encryption method based on a five-dimensional conservative hyperchaotic system according to claim 1 is characterized in that: Calculating a second Hash value based on the first scrambled graph, and generating a second key sequence based on the second Hash value, including: Obtaining a row matrix, a column matrix, and a diagonal matrix of the first scrambled graph; Calculate a second primary hash value using SHA-384 based on the row matrix, the column matrix, and the diagonal matrix; Based on the second primary hash value, a second binary hash value is calculated using SHA-256; The second hash values ​​are grouped and converted into decimal form to generate a second key sequence.

6. The multi-key image encryption method based on a five-dimensional conservative hyperchaotic system according to claim 5 is characterized in that: The second initial value is brought into the five-dimensional conservative hyperchaotic system for iterative operation, thereby generating a pseudo-random sequence used for forward diffusion and a pseudo-random sequence used for reverse diffusion, including: Bringing the second initial value into the five-dimensional conservative hyperchaotic system and iterating it for a preset number of times to generate five groups of chaotic pseudo-random sequences; A pseudo-random sequence used for forward diffusion and a pseudo-random sequence used for reverse diffusion are generated based on the second and fourth groups of chaotic pseudo-random sequences.

7. The multi-key image encryption method based on a five-dimensional conservative hyperchaotic system according to claim 1 is characterized in that: Calculating a third Hash value based on the diffusion map, and generating a third key sequence based on the third Hash value, comprising: Obtaining a row matrix, a column matrix, and a diagonal matrix of the diffusion map; Calculate a third primary hash value using SHA-256 based on the row matrix, the column matrix, and the diagonal matrix; Based on the third primary hash value, a third binary hash value is calculated using SHA-256; The third hash values ​​are grouped and then converted into decimal form, thereby generating a third key sequence.

8. The multi-key image encryption method based on a five-dimensional conservative hyperchaotic system according to claim 1 is characterized in that: Bringing the third initial value into the five-dimensional conservative hyperchaotic system for iterative operation, thereby generating a chaotic pseudo-random sequence used for the second scrambling, including: Bringing the third initial value into the five-dimensional conservative hyperchaotic system and iterating it for a preset number of times to generate five groups of chaotic pseudo-random sequences; A chaotic pseudo-random sequence used for the second scrambling is generated based on the third and fifth groups of chaotic pseudo-random sequences.

9. A multi-key image encryption device based on a five-dimensional conservative hyperchaotic system, characterized in that: include: Chaotic system building module, which is used to build a five-dimensional conservative hyperchaotic system; A first chaotic pseudo-random sequence generation module is used to obtain a plaintext image to be encrypted, calculate a first hash value based on the plaintext image, and generate a first key sequence based on the first hash value; obtain the missing initial value of the five-dimensional conservative hyperchaotic system as the first initial value through the first key sequence; bring the first initial value into the five-dimensional conservative hyperchaotic system for iterative calculation, thereby generating a chaotic pseudo-random sequence used for the first scrambling; A first scrambling module, which is used to scramble the plaintext image according to the chaotic pseudo-random sequence used for the first scrambling to generate a first scrambling graph; A second chaotic pseudo-random sequence generation module, which is used to calculate a second Hash value based on the first scrambled graph, and generate a second key sequence based on the second Hash value; and obtain the missing initial value of the five-dimensional conservative hyperchaotic system as the second initial value through the second key sequence; Bringing the second initial value into the five-dimensional conservative hyperchaotic system for iterative operation, thereby generating a pseudo-random sequence used for forward diffusion and a pseudo-random sequence used for reverse diffusion; A diffusion module, which is used to diffuse the first scrambled image according to the pseudo-random sequence used for forward diffusion and the pseudo-random sequence used for reverse diffusion to generate a diffusion map; A third chaotic pseudo-random sequence generation module is used to calculate a third hash value based on the diffusion map, generate a third key sequence based on the third hash value; obtain the missing initial value of the five-dimensional conservative hyperchaotic system as a third initial value through the third key sequence; bring the third initial value into the five-dimensional conservative hyperchaotic system for iterative calculation, thereby generating a chaotic pseudo-random sequence used for the second scrambling; The second scrambling module is used to scramble the diffusion image according to the chaotic pseudo-random sequence used in the second scrambling to generate a ciphertext image.

10. A storage medium, characterized in that: The storage medium includes a stored program, wherein when the program is run, the multi-key image encryption method based on a five-dimensional conservative hyperchaotic system as described in any one of claims 1 to 8 is executed.

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