Hyper-chaotic system-based secret key dynamic selection image encryption algorithm

Abstract

The invention relates to a hyper-chaotic system-based secret key dynamic selection image encryption algorithm. The algorithm mainly comprises the following steps of arranging original plaintext images into an image array P, using a hyper-chaotic system to generate a chaotic sequence, and performing grouping; generating a forward scrambling secret key K1 with the combination of a KSSG and KS dynamic selection mechanism based on a plaintext and performing forward scrambling of the P to obtained P1; generating a forward diffusion secret key K2 with the combination the KSSG and KS dynamic selection mechanism and performing forward diffusion of the P1 to obtain a P2; generating a backward scrambling secret key K3 with the combination of the KSSG and KS dynamic selection mechanism and performing backward scrambling of the P2 to obtain a P3; and generating a backward diffusion secret key K4 with the combination the KSSG and KS dynamic selection mechanism, performing forward diffusion of the P3 to obtain a P4, and performing regrouping of the P4 to obtain a final cryptograph image. The abovementioned method provided by the invention increases the secret key space, enables the security, the encryption effect and the secret key sensitivity to be higher and the anti-attach performance to be stronger, and is easy in hardware implementation.

Description

technical field [0001] The invention relates to an image encryption method, in particular to an image encryption algorithm based on dynamic key selection of a hyperchaotic system. Background technique [0002] Today, with the rapid development of smart devices, the Internet of Things, high-definition multimedia, and network technology, the transmission of most information in our lives, such as documents, audio, video, and especially image information, is inseparable from the support of the network. On the one hand, the network brings convenience to people's life, but on the other hand, some criminals will use the network to steal information, which brings great hidden dangers to people's information security, so the security and safety of information in the process of network transmission Confidentiality issues are also more and more people's attention and attention. Generally speaking, image information has the same characteristics, and they all have the characteristics of...

AI Technical Summary

Problems solved by technology

However, the currently used image encryption algorithms have the following problems: First, in the scrambling stage, most encryption algorithms lack the connection with the plaintext, although some encryption algorithms consider the connection with the plaintext, but when a certain pixel When a change occurs, the scrambling effect still cannot spread to the entire image, and the scrambling effect only affects the pixels behind the pixel change, so that the stealer can find the scrambling law through a simple comparison, which makes There are huge loopholes in the security of images; second, digital images are discrete finite point sets composed of pixels one by one, and will return to the original state after multiple times of scrambling and transformation, so as long as the stealer knows the encryption algorithm , it can be decrypted violently, and through multiple iterations, the plaintext image will be obtained within a limited number of steps; third, no matter in the scrambling stage or in the diffusion stage, for different images, as long as the initial value is the same as the control parameter , the key used for encryption is the same, the key cannot be dynamically selected according to the difference of plaintext pixels, and the corresponding chaotic system must generate the key in the scrambling and diffusion stages, which not only increases the system cost, and reduces the security of the image encryption algorithm; fourth, in the past, the low-dimensional chaotic system is generally used to encrypt the image, and the chaotic sequence generated by the low-dimensional chaotic system is only formed through simple repeated iterations, and the security is not good enough. And the calculation accuracy of the computer may also lead to the chaotic sequence of the low-dimensional chaotic system having a relatively short periodicity and poor randomness, which provides a breakthrough for the cracking of the image

The Chinese patent application number 201310412691.1 discloses a color image encryption method based on chaotic sequence and hyperchaotic system. In the scrambling stage of image encryption, the method uses the chaotic sequence generated by the one-dimensional chaotic system to scramble the image pixels. The scrambling process lacks the connection with the plaintext. In the diffusion stage, the hyperchaotic system is used to generate the key used for diffusion, which increases the overhead of the system and increases the complexity of the hardware. Its security needs to be improved.

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