Like a timed escrow service? 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

Like a timed escrow service? 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.