A stack-based chaotic algorithm for encryption of colored images

In this paper, a new method is presented for encryption of colored images. This method is based upon using stack data structure and chaos, which make the image encryption algorithm more efficient and robust. In the proposed algorithm, a series of data whose range is between 0 and 3 is generated using the chaotic logistic system. Then the original image is divided into four sub-images, which are subsequently pushed into the stack based on the next number in the series. In the next step, the first element in the stack, which includes one of the four sub-images, is popped, and this image is divided into four other parts. Then, based on the next number in the series, four sub-images are pushed into the stack again. This procedure is repeated until the stack is empty. Therefore, during this process, each pixel unit is encrypted using another series of chaotic numbers (generated by the Chen chaotic system). This method is repeated until all pixels of the plain image are encrypted. Finally, several extensive simulations on well-known USC datasets are conducted to show the efficiency of this encryption algorithm. The tests performed show that the proposed method has a really large key space and possesses a high-entropic distribution. Consequently, it outperforms the other competing algorithms in the case of security.