Enhanced chaotic key-based algorithm for low-entropy image encryption

As computing power of today´s computer enhances rapidly, secure encryption is getting harder and the need for powerful secure encryption methods becomes inevitable. To avoid brute-force attacks it is necessary to have a larger key space, which makes the chaotic systems more attractive. In order to sufficiently apply confusion and diffusion rules for an image data with any entropy structure, a two-dimensional chaotic system, which has high sensitivity to initial states, has been utilized in this study. The fact that adjacent pixels of an image have naturally close values makes it easier for crackers to perform statistical analysis. So, two chaotic functions are used to disrupt correlations among them, one for shuffling pixel positions and one for changing pixels values. Even with low entropy images the proposed algorithm has been proved to be more secure and faster than the previous algorithms.