In this thesis, an optical color image cryptosystem with a color image and data hiding scheme is proposed. In the proposed optical cryptosystem, a secret color image is embedded into host image of the same size to become a stego-image. The secret color image is hidden in the phase term of the host image. Then the stego-image is encrypted by the optical cryptosystem which employs a double random phase encoding algorithm. During the encoding process, secret data is embedded into the encrypted image by an adaptive steganographic technique. The secret image and data delivery is accomplished by hiding the image into the host image and embedding the data into the encrypted stego-image. In comparison with the traditional hiding scheme, a high data embedding capacity and high visual quality of the decrypted host and secret images are achieved. Experimental results show that the proposed image and data steganographic cryptosystem provides large data hiding capacity and high reconstructed image quality.
