s A Hybrid Security System Based on Bit Rotation and Chaotic Maps

Background: This paper presents an image security system by combining bit rotation with block based chaotic maps cryptography. Methods: The system uses permutation technique that divides the image into blocks before applying right/left rotation of bits to the pixel values based on a randomly generated key. Then, the image blocks are fused together. A scrambling operation followed by chaotic map is applied on the rotated image to diffuse the image pixels using another randomly generated key. The chaotic map scatters all the pixel positions in the image. The decryption is the complete reversal operation of the encryption process. Results & Conclusion: The performance of the proposed technique is evaluated using several metrics: Histograms of both original and cipher images, correlation of adjacent pixels and correlation between the original and cipher images, Number of Pixel Change Rate (NPCR), Unified Average Changing Intensity (UACI), Mean Square Error (MSE), and Peak Signal to Noise Ratio (PSNR). The results indicate a very secure technique to protect all types of images.