Lightweight Multi-Layered Encryption and Steganography Model for Protecting Secret Messages in MPEG Video Frames

Ensuring the secure transmission of secret messages, particularly through video—one of the most widely used media formats—is a critical challenge in the field of information security. Relying on a single-layered security approach is often insufficient for safeguarding sensitive data. This study proposes a triple-lightweight cryptographic and steganographic model that integrates the Hill Cipher Technique (HCT), Rotation Left Digits (RLD), and Discrete Wavelet Transform (DWT) to embed secret messages within video frames securely. The approach begins with encrypting the secret text using a private key matrix (PK1) of size 2 × 2 up to 6 × 6 via HCT. A second encryption layer is applied using a dynamic private key (PK2) derived from the RGB pixel values of the video frame, resulting in a rotated cipher. The doubly encrypted message is then embedded into the video frames using the DWT method. Upon transmission, the concealed message is extracted using inverse DWT and decrypted in two steps—first with PK2 and then with the inverse of PK1. Experiments conducted using MPEG video sequences and message lengths ranging from 10 to 300 bytes demonstrate strong performance in terms of Mean Square Error (MSE), Peak Signal-to-Noise Ratio (PSNR), and Correlation Coefficient (CC) between original and encrypted messages. The similarity between original and stego frames is further validated using Structural Similarity Index (SSIM), Mean Absolute Error (MAE), Number of Pixel Change Rate (NPCR), and Unified Average Changing Intensity (UACI). Results confirm that utilizing video frames to generate PK2 offers superior security compared to static key images. Moreover, the indistinguishability between original and stego frames highlights the method’s robustness against visual and statistical attacks.