Can content providers not include a digital signature in the video metadata? Then you can authenticate the video against the original provider, a bit like the g

Can content providers not include a digital signature in the video metadata? Then you can authenticate the video against the original provider, a bit like the green padlock next to the URL bar in Chrome. Even better (though I'm not sure this technology exists yet), some some kind of "rolling signature", available running along side the video in metadata, that a media player can use to validate the authenticity of the video at that point in time. Then you don't need the full video to be able to verify the source.