Commitment scheme

In cryptography, a commitment scheme is a way for a someone to tell something to someone without letting other people know. Someone would do this to make sure they can prove who they are. Someone also might do this to make sure that someone does not cheat.
This is done by using a one-way function to change a string into a hash. This is called the "commit phase". Later, if someone needs to prove that they were the one who made the commitment, then they can tell people the original string they used. This is called the "reveal phase".