Could you create a system which allows some encrypted messages to only be decrypted after/at a given time t and without any authority?<p>There would be so cool applications of such a system, imagine if someone (like Snowden) want to share to the world some important document but which only are auto-decrypted in the future, whatever happen to the person.<p>Do you think this will ever be possible? I'm afraid this need the time to be provable?
Like a timed escrow service?<p>In your example you would be relying on a system clock in the end, which is easily manipulated. Better to use a trusted person or machine who can reveal the data or the key to the data at a given time, or to use a dead man's switch.
The easiest way to achieve this is to encrypt and release the data the set up some kind of timed mechanism to release the decryption key. I believe Julian Assange has already done something similar.