| 摘要 |
<p>A method and apparatus for verifying the authenticity and integrity of an ordered sequence of digital video frames (60), without having access to the original recording, by embedding therein a respective series of digital signatures (66) based on a secret key (61), or keys, and on the video content of respective frames (69). Signatures are camouflaged by embedding in transform coefficients of a transformed representation of the video data in parts of the frame corresponding to motion. If there is sufficient motion to contain all of the signature bits, a supplementary technique embeds in high-texture areas of a frame. A final fall-back is to embed in a pre-defined default zone. A method of predicting when supplementary embedding is needed enables the process to be applied in a single pass allowing real-time operation. Verification is done during decoding by comparing, for identiy, embedded signatures with signatures calculated anew using the method employed to embed.</p> |
