Research On Image Encryption Algorithm Based On Iterative Retrieval Process

With the rapid development of computer and Internet technology,massive private information is transmitted in the Internet, which produces a series of information security issues, such as: illegal theft, monitoring, dissemination of data information, etc.. As an important information carrier, image is also facing increasingly serious security problems. In recent years, with the development of optical image encryption technology, more and more experts and scholars have been involved in the field of image security. In many of the image encryption algorithm, iterative retrieval process is very common. Therefore, this paper studies and proposes several image encryption algorithms based on it, and the main research works are summarized as follows:First, a color image encryption by using Yang-Gu mixture amplitude-phase retrieval process is proposed. The color image is decomposed and scrambled. Subsequently, each component is encrypted using the iterative amplitude-phase retrieval process in the GT domain.Finally, three result components are combined into a color image as the ciphertext. The ciphertext can be more convenient for storage and transmission because it is real-value function. The validity and security of the scheme are proved by the key sensitivity analysis,noise attack, occlusion attack, and statistical analysis.Second, on the basis of the bits coding and the single-intensity-recording phase retrieval algorithm, a QR code encryption and compression scheme is proposed. At the beginning, the QR code is encoded using its bits. Subsequently, the double random phase encoding technique is utilized to encrypt it, and only the intensity of the result is recorded. The intensity is scrambled to obtain the final ciphertext. Similarly,the ciphertext image is real-value, which is convenient to store and transmit. A series of simulation experiments show that the scheme has strong resistance to Gauss noise attack, and also has strong ability to resist statistical analysis.Finally, image compression and encryption scheme based on the cascaded compressive sensing is proposed. In this scheme, the plaintext image is transformed by the DCT. And then,the matrix is compressed twice in the DCT domain. After each compressive sensing process,the result is scrambled to improve the randomness and security of the system. Subsequently,the obtained result will be normalized. In the final stage, the exclusive or(XOR) operation is executed on the normalized matrix and a random matrix which is in the same range, and the ciphertext image can be gained. This algorithm can realize image compression and encryption,simultaneously. And the real-value encryption result facilitates the storage, management and transmission. The simulation results show the effectiveness and reliability of the proposed scheme.