I don't know how to call this kind of proof in English, but maybe if I explain it a little bit further you'll get the idea.

Basically I want to create video/audio proof that something was shot in 2013 and have this "proof" video as evidence later, in 2015.

The question is what to do so the people will believe that the video from back in the days is authentic and not fabricated in 2015.

  • I was thinking that it should be one-taker and that
  • it should contain some evidence of the date and time and
  • some things that were unique for that time and don't exist anymore or something like that e.g. building that will be destroyed, people who will be dead in 2 years ;D etc.

But I need something easier to accomplish, because the newspapers and TV, radio could be faked. Something more bullet proof would be needed.

Any ideas how to accomplish that? Thanks in advance for every take on this. I am really curious how would you solved this problem.

  • 3
    Now with good chroma keying methods and other digital tricks available to anyone, you probably won't get anything bullet-proof. Macabrely, speaking to someone terminally ill and perhaps hugging them is the only thing that would seem really convincing to me; I don't think this could be faked so well that a close relative of the person in question wouldn't notice. But that's for several reasons not a idea you should consider. – If you need to proove something happened at a particular time, a video just isn't the right way; get something signed by a notary instead. Aug 7, 2013 at 11:15

2 Answers 2


There isn't any way to do it within the video. You can easily prove a video was made (or altered) after a particular time, but you can't prove that it happened before a particular time via the media itself, since you could edit things in from previous time to make it look that way.

The non-video answer would be to generate a signature of the video file and get it cryptographically signed by a reliable time stamping service. This would prove that the video files had been unaltered since the time the stamp was applied. Most Certificate Authorities can do this. I personally use StartSSL because they are pretty cheap but reasonably well respected.

Alternately, you can have a document from a notary about when the video was made, though that won't prove it wasn't altered in some way. The notary may have more legal baring than a particular CA's time server though depending on if anything causes a loss of faith in the Certificate Authority.


Hash the video and publish the hash of the video on any blockchain that is likely to still be there in the future. Later you can prove the video existed at the time its hash was published.

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