Two-Layer Security for Image Encryption: A Switched System Approach

This paper proposes an image encryption-decryption scheme with two-layer security. In the first layer, an image is encrypted by a switched system, using the concept from control theory. Also, from this switched system, a random key matrix will be generated while encrypting in the first layer. This key matrix is used to diffuse the image pixels from the first layer, providing the second layer of security. Then, in the decryption stage, the random key matrix plays a role as a cryptographic key and the optimization method will be used to decrypt the second layer encrypted image. The flatness property of the switched system that makes the plain image to be recovered from the encrypted image of the first layer. This scheme is to enhance the security in image encryption and also fortifies the encryption process against sophisticated attacks while maintaining computational efficiency. Finally, the effectiveness of the proposed scheme is evaluated by simulation, then assessing it to different types of cryptanalytic analyses such as information entropy analysis, adjacent pixel correlation, differential attack analysis, key sensitivity analysis, and histogram analysis. The numerical values that can achieved by the proposed schemes are entropy 7.996, adjacent pixel correlation for horizontal -0.0012, vertical -0.0039, diagonal 0.0005; and differential attack analysis with Number of Pixels Change Rate 0.9963 and Unified Average Changing Intensity 0.3341.