Video Encryption and Decryption using Sine Transformed 3-D ILM

Image and video encryption has emerged as an important field of research among the researchers. The results of chaos based cryptographic technologies is gaining attention for the protection of digital data. This paper presents a confusion-diffusion based video encryption algorithm that uses Secure Hashing Algorithm (SHA-2) and a sine transformation-based chaos function. The proposed method is split into three major parts. Firstly, SHA-2 is used with sine transformed Intertwining Logistic Map (ST-ILM) to create the chaotic sequence. The ST-ILM has essential characteristics of randomness as its bifurcation diagram is uniform along with positive Lyapunov exponent and higher entropy. In the second part, each frame of the video is subjected to a sequence of processes, namely permutation (confusion), rotation, and substitution to obtain cipher frame. During the third part, the encrypted frames are reorganized to produce final encrypted video. To ensure that every video frame is encrypted with a distinct chaotic key without creating inter-frame dependency, a frame-adaptive key generation approach is presented in which the initial ST-ILM seed is dynamically disturbed using the frame index. A feedback-based diffusion method has been used, in which each cipher pixel depends on chaotic index mapping and previously encrypted pixels, which greatly increases resistance to differential attacks. The introduced chaotic algorithm has been verified on various encryption and decryption parameters. The findings proved that effectiveness of the proposed video encryption scheme and exhibits greater security compared to several previously proposed techniques.