Digital image encrypting and decrypting method

Abstract

The invention discloses a digital image encrypting and decrypting method comprising the following steps of: appointing the gray value range of an encrypted image according to an image to be encrypted; dividing the image to be encrypted into pixel blocks with the same size, and computing a pixel mean value by virtue of a formula; generating a sub-secret key according a 48-bit binary system key stream preset by a user, and building Logistic mapping according to the pixel mean value; converting into a binary sequence according to the number of floating points generated by the Logistic mapping, and taking the binary sequence as the sub-secret key of the next pixel block; scrambling the pixel in each pixel block based on the improved Arnold conversion, and combining the scrambled pixel blocks into a matrix; and replacing the adjoining pixels in the matrix, so that a ciphertext image can be formed. According to the requirement of a user, the image can be encrypted by means of different numbers of sheaves, various filtering attacks can be resisted, and the invariability of the pixel mean value of the image can be realized, so that the whole style and feature of the original image can be maintained.

Description

technical field [0001] The invention relates to the field of image processing, in particular to a digital image encryption and decryption method. Background technique [0002] With the continuous development of the Internet and communication technology, digital images, as the most intuitive, vivid and vivid information carriers, are used more and more widely in daily life, and gradually become a mainstream way of expressing network information. , not subject to geographical restrictions, and the cost is very low and the efficiency is high. The sales model of traditional photo dealers has also gradually changed to an e-commerce model. Under this commercial background, in order to solve the problem that customers can preview the basic information of the picture before deciding whether to buy a digital picture, a digital image selection encryption mode is proposed. Although the selected encrypted image still retains its main content, but Visually, it is rougher than the origi...

AI Technical Summary

Problems solved by technology

[0006] The technical problem to be solved by the present invention is to provide a digital image encryption and decryption method for the defects of uncontrollable encryption and poor image quality in the prior art. Encryption, and can resist various filtering attacks at the same time, realize the image pixel mean value unchanged, in order to maintain the overall style of the original image

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