Improving Security of Double Random Phase Encoding with Chaos Theory Using Fractal Images

This study presents a new method based on the combination of cryptography and information hiding methods. Firstly, the image is encoded by the Double Random Phase Encoding (DRPE) technique. The real and imaginary parts of the encoded image are subsequently embedded into an enlarged normalized host image. DRPE demands two random phase mask keys to decode the decrypted image at the destination. The two random phase masks are regenerated by the chaos theory using a fractal image. To enhance its security, instead of sending the second phase mask directly, the initial conditions and the parameter of the chaotic map and the fractal image are transferred to the authorized user through a secure channel. Experimental results reveal that the proposed method not only enjoys high security but also resists the commonplace attacks.