A Chaos-based Color Image Encryption Algorithm

Chaos-based encryption appeared recently in the early 1990s as an original application of nonlinear dynamics in the chaotic regime. In this paper, a new image encryption algorithm is presented. In order to achieve security needs, an external secret key of 80-bit and two chaotic logistic maps are employed, and the initial conditions for the both logistic maps are derived by the external secret key. Firstly, the first logistic map is used to shuffle the position of plain-image pixels in the spatial-domain, so we can get shuffled image. Then the second logistic map is used to change grey value of shuffled image pixel and cipher-image appears. The relationship between the cipher-image and the plain-image is confused through the above two processes. The experimental results demonstrate that the proposed algorithm has large enough key space to resist all kinds of brute force attack and the distribution of grey value of the encrypted image has a random-like behavior, in addition, which is very sensitive to the secret key.