A Novel Cosine Transformed Chebyshev Chaotic Map based Image Encryption

Digital chaos has become a popular approach for developing secure and efficient image encryption techniques. On the other hand, image encryption techniques are vulnerable to the differential, statistical, and known/chosen plaintext attacks. This paper creates a novel approach for encrypting medical images using the novel cosine transformed Chebyshev chaotic map. The proposed novel chaotic map is analyzed using parameters like bifurcation diagram and Lyapunov Exponent. In the proposed approach, first, both seed and control parameter are initialized using the secret key and initial vector. After that, the intermediate key for each color image component is generated using the propoed chaotic map and the shared key. Finally, the cipher image is created using the combination of the intermediate key and the chaotic map. This scheme has been analyzed using various security parameters like brute force attack, known/chosen plaintext attack, Number of Pixel Change Rate (NPCR), Unified Averaged Changed Intensity (UACI), Corrleation Coefficient (CC), and Entropy.