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ABSTRACTA novel data hiding approach is being proposed in this article, camouflaging secret data within a very high-quality video object. The proposed algorithm utilizes Discrete Wavelet Transform (DWT) and Discrete Cosine Transform (DCT) to hide image data, preprocessed using Arnold Transform. The novelty of this approach lies in the combination of five factors, which are – use of very high-resolution Ultra HD 4 K video as a cover object; Use of DCT coefficient in Scene Change Detection to identify cover frame; Scrambling the secret image by Arnold Transformation; Use of DCT-DWT in embedding and extraction process to that hide data in the blue plane of the RGB frame; and lastly, use of three different keys for data hiding to secure the proposed method against attacks, by adhering the Kerckhoff’s principle of a cryptosystem. Several quality metrics like Structural Content, Peak Signal-to-Noise Ratio, Normalized Cross-Correlation, Average Difference, Maximum Difference, and Normalized Absolute Error have been calculated to validate the imperceptibility. This method has also been validated against different steganalysis attacks like random cropping, rotating, resizing, noise addition, filtering, histogram attack, and lastly, compared with existing data hiding methods to prove superiority.

In this paper, a new substitution-diffusion type chaos-based cryptosystem is proposed, which can encrypt greyscale images having arbitrary resolution. In substitution, image pixels are permuted using a modified form of the discretised 2-D Baker map, followed by a two-step diffusion approach, which employs a chaotic logistic map. The proposed cryptosystem is resistant to brute force attacks (measured by key-space and key-sensitivity analysis), statistical attacks (tested by histogram and chi-square test) and differential attacks (measured against NPCR, UACI, and hamming distance); the proposed method has also been tested for encryption quality, correlation analysis, entropy analysis, and performance analysis by measuring encryption speed as well as time complexity. Therefore, it is sufficiently secured to be used in real-world applications. To prove the unparalleled outcome of the proposed system, four sets of comparisons have been presented with respect to NPCR and UACI, Encryption throughput, and, lastly, with similar and non-similar existing cryptosystems.

According to the International Telecommunication Union, currently 51% of the world's population has internet access, out of which over 80% prefers video sharing. Henceforth for secure communication, secret data hiding in video can be a viable option. Here a blind, key-based video steganography has been proposed which can hide RGB image within a colour video. The novelty of this approach lies in the security imposed by various factors including scene change detection by maximum likelihood estimation; pre-processing of secret image by Fibonacci encryption and discrete wavelet transform based keyed embedding technique, which can hide colour images without any perceivable differences and does not require cover video frame during extraction. Quality of the method has been analysed by peak signal to noise ratio, structural similarity index, normalised absolute error and correlation coefficient; robustness has been tested against random cropping, rotating, resizing and histogram equalization; comparison with the literature demonstrates its superiority.