Color image encryption and decryption method and system based on double-chaos cross diffusion

Abstract

The invention discloses a color image encryption and decryption method and system based on double-chaos cross diffusion. Firstly, parameters of Logistic and ChebyShev iteration are randomly generated, initial secret keys needed by Logistic and ChebyShev iteration are input, after a transit state is eliminated through multiple times of iteration, Logistic and ChebyShev are used for carrying out iteration three times respectively, iteration results serve as initial secret keys used during encryption respectively, and therefore secret key space is actually increased. Then a pixel point in an image is taken, if the value corresponding to the position of the pixel point is an odd number, an encryption key is obtained through ChebyShev iteration, or else the encryption key is obtained through Logistic iteration, and therefore the dependency between adjacent pixel points is reduced. Then R, G and B channels of the pixel point and R', G' and B' of the former encrypted pixel point are subjected to difference or operation for diffusion. The iteration frequency is reduced on the premise of guaranteeing safety, the encryption time can be shortened, efficiency is improved, and the method and system are especially suitable for image encryption of mobile equipment such as mobile phones and tablet computers with the high real-time performance requirement.

Description

technical field

[0001] The invention relates to the field of image encryption, in particular to a color image encryption and decryption method and system based on double chaotic cross-diffusion. Background technique

[0002] With the rapid development of information technology, more and more image data are transmitted on the network, and the privacy, security and reliability of image information have been paid more and more attention by people. For this reason, encrypted transmission is required. When traditional encryption algorithms encrypt images, they first need to convert the image data into one-dimensional data, and then convert it into two-dimensional or three-dimensional data when decrypting. At the same time, because image data also has the characteristics of large amount of information and high redundancy, Therefore, the traditional encryption algorithm encrypts and decrypts the image, which has low efficiency and poor security.

[0003] Image encryption based on...

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