A New Evaluation of Video Encryption Security with a Perceptual Metric

Peak Signal to Noise Ratio (PSNR) and Structural SIMilarity (SSIM) are metrics initially used to evaluate the visual quality of compressed images or sequences compared to the original ones. By analogy to compressed sequences, researchers use these metrics to evaluate the degradation of encrypted sequences. Video encryption algorithms target a maximum scrambling so that their contents become imperceptible to the human visual system. The distortion of PSNR and SSIM values comes from both compression and encryption. The use of these metrics to measure the degradation of joint compressed and encrypted sequences cannot give us a precise evaluation of the distortion. For a better evaluation, a Contrast Sensitivity Function (CSF) metric was used. This article aims to provide a perceptual evaluation of the encryption effect for the H.264 Advanced Video Coding compressed and encrypted sequences, using the CSF metric. The visual quality of the encrypted video is degraded and proven bad from different viewing distances.