A Digital Image Encryption Algorithm Based A Composition of Two Chaotic Logistic Maps

The chaos based cryptographic algorithms have suggested several advantages over the traditional encryption algorithms such as high security, speed, reasonable computational overheads and computational power. This paper introduces an efficient chaos-based stream cipher, composing two chaotic logistic maps and a large enough external secret key for image encryption. The external secret key is used to derive the initial conditions for the chaotic maps, and is employed with the two chaotic maps to confuse the relationship between the cipher image and the plain image. In the encryption phase, the pixels are encrypted using an iterative cipher module based feedback and data-dependent inputs mechanism for mixing the current encryption parameters with previously encrypted information. To make the cipher more robust against any attack, the secret key is modified after encryption of each pixel of the plain image. The results of several experimental, statistical analysis and key sensitivity tests show that the proposed image encryption scheme provides an efficient and secure way for real-time image encryption and transmission.