Toward a secure video watermarking in compressed domain

Collusion attack is a major concern in the field of video watermarking. To overcome this problem, a classic approach is exploiting a content-based key in order to select the embedding locations. This key should be chosen carefully especially in the blind embedding to prevent the possibility of any alteration after inserting the watermark. Extracting a robust content-based key is a more challenging issue in blind compressed domain watermarking since the syntactic elements such as DCT residuals may change after re-encoding even without inserting the watermark. Consequently, it is really desirable to derive a robust content-based key using just the syntactic elements of compressed video sequences. In this paper, we utilize the inter-mode values, as available information, to provide a robust content-based key. The key is evaluated and found to be robust against common compressed domain video watermarking attacks. In addition, the key generation mechanism is appropriate for real-time applications since the full decompression and recompression of the video stream are avoided. (C) 2019 Elsevier Ltd. All rights reserved.