A method and device for digital image encryption based on fractional transformation

Abstract

The embodiment of the invention provides a digital image encryption method and apparatus based on fractional order transformation, and belongs to the technical field of digital image encryption. The digital image encryption method based on fractional order transformation includes the steps: acquiring the gray value of each pixel of an original image and the image matrix corresponding to the original image; according to the image matrix corresponding to the original image and a preset first scrambling algorithm, determining a spatial domain scrambling image matrix; presetting first fractional order transformation for the spatial domain scrambling image matrix, and obtaining a transformation domain image matrix; according to the transformation domain image matrix, the line number value and the row number value of the image matrix corresponding to the original image, the gray value of each pixel and a preset first diffusion algorithm, determining a diffusion matrix; and according to the diffusion matrix, the transformation domain image matrix and the preset first scrambling algorithm, determining an encryption image matrix. The digital image encryption method based on fractional ordertransformation can improve the anti-noise and anti-loss performance of the cryptograph image during the practical transmission process, and can reduce the bandwidth cost generated during the image transmission process.

Description

technical field [0001] The invention relates to the technical field of digital image encryption, in particular to a method and device for digital image encryption based on fractional transformation. Background technique [0002] With the rapid development of computer and multimedia technology, the transmission of digital images in the network is very frequent. Some image information, such as ID card information pictures, military base pictures and design drawings, etc., not only involves personal privacy, but also has a bearing on national security, so encrypted transmission must be adopted. The two most commonly used encryption algorithms are the image encryption algorithm based on the spatial domain and the image encryption algorithm based on the transform domain. [0003] The image encryption algorithm based on the space domain directly performs a series of processing on the digital image in the space domain, and the typical processing method is the "scrambling-diffusion...

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Problems solved by technology

[0004] However, there are some problems in the digital image encryption method based on the prior art, whether it is an image encryption algorithm based on the space domain or the transform domain.

The main disadvantage of the image encryption algorithm based on the spatial domain is that the anti-noise and anti-loss performance in the actual transmission process of the image is poor; while the main disadvantage of the image encryption algorithm based on the transform domain is that the bandwidth cost is increased during the image transmission process of the transform domain, and Statistical properties of transform domain images are often incomplete

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