This is probably what you want: http://proofofexistence.com/

Though I'm not sure how large a file you can input; I've only done it with documents and pictures. I imagine a <20MB video file would be fine, though.


I dropped a Casascius coin in my daughter's piggy bank when she was born a couple years ago. She was probably therefore the youngest bitcoin holder for a while.

Now she's talking and "bitcoin" is a household word. Bitcoin-as-money will seem totally normal and obvious to her.