Obtaining the hash value of a video, then embedding that hash value into a secure block chain is one approach that gives evidence that a specific video (or any

Obtaining the hash value of a video, then embedding that hash value into a secure block chain is one approach that gives evidence that a specific video (or any other document) existed before some point in time. See, for example: https://petertodd.org/2016/opentimestamps-announcement https://petertodd.org/2016/opentimestamps-announcement Editing the video after the fact changes its hash value, thereby invalidating the timestamp on the altered video.