A digital image encryption method based on three-dimensional chaotic system

Abstract

The present invention is a digital image encryption method based on a three-dimensional chaotic system, which belongs to the technical field of image encryption. The scrambling method adopted in the present invention is based on a pixel exchange mechanism, which effectively overcomes the periodicity, fixed points and problems of the classical chaotic scrambling method. The shape of the image has three disadvantages; in the process of using the key stream elements, each key stream element performs a cyclic shift operation under the control of the plaintext pixel to achieve the purpose that the key stream is related to the plaintext; due to the cyclic shift Bit operations are bit operations that are close to the underlying hardware, have extremely high execution efficiency, and will not have a significant impact on the operating efficiency of the system; in addition, since the plaintext does not change the iterative process of the chaotic system and the quantization process of the state variables, but The value of the keystream element is dynamically changed during the encryption process, so the keystream is reusable, which has potential advantages for high-security applications that require multiple rounds of encryption.

Description

technical field [0001] The invention belongs to the technical field of image encryption, and in particular relates to a digital image encryption method based on a three-dimensional chaotic system. Background technique [0002] In recent years, with the rapid development of multimedia and computer network technology, digital images, as the most intuitive information carrier, have become an important means for people to communicate information. More and more digital images are disseminated in open networks represented by the Internet and wireless networks, which greatly facilitates information access and sharing; at the same time, commercial, financial, medical, scientific research, military, political, etc. The transmission of image information in many sensitive areas in an open network environment has huge security risks, and often encounters various potential human attacks, including illegal acquisition, tampering and release of information, etc., causing huge losses to inf...

AI Technical Summary

Problems solved by technology

[0014] ①A digital image is composed of discrete pixels on a two-dimensional plane; therefore, the chaotic map used to realize image scrambling must also perform corresponding discretization operations; the chaotic system is a nonlinear non-periodic system, but after Discretized chaotic systems are generally no longer aperiodic; this means that an image may return to its initial state after being scrambled for several rounds by the discrete chaotic map, thus losing the meaning of scrambling;

[0015] ②Existing area-preserving reversible chaotic maps, such as cat maps, baker maps, and standard maps, can only be applied to square images; for more general rectangular images, they must first be converted into squares, which undoubtedly increases the calculation of the system ;

[0016] ③ For common mappings such as cat, baker, and standard, the coordinate point (0, 0) is a fixed point, that is, when using this type of mapping to scramble the image, no matter how many parameters are used, the first pixel in the upper left corner of the image will remain fixed; in order to overcome this problem, special processing is required for these fixed points, which also increases the calculation of the system;

[0019] An effective strategy to solve this problem is to associate the keystream elements with the plaintext; the current mainstream method is to let the plaintext participate in the generation process of the keystream elements, and its typical representative is the document "A chaos-based image encryption algorithm with variable control parameters, Chaos, Solitons and Fractals, 41(4), 1773-1783, 2009" (SCI impact factor 1.503, cited 145 times, hereinafter referred to as literature [1]), this method controls the generation of The number of iterations of the chaotic system required for a key stream element is used to achieve the purpose of the key stream being related to the plaintext, but this method has two disadvantages: ① the increase in the number of iterations reduces the efficiency of the encryption system; ② due to the key The correlation between the stream generation process and the plaintext, the key stream can no longer be reused by different rounds of encryption operations, that is, each round of encryption must independently generate a new key stream, which also reduces the efficiency of the system to a certain extent

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