Zero-knowledge Proof refers to the system which one can prove to the verifier a given statement is true without revealing additional information.
At present, the highly anonymous cryptocurrency Zcash ensures anonymous transactions with “Zero-knowledge Proof”.
For example, A wants to prove to B that he possesses the key to a certain room, and that the room can only be unlocked with the key
Now, A can choose to hand the keys over to B and B uses the key to unlock the room, proving that A holds the correct key.
Alternatively, A himself can unlock the room using the key and showing an item to B, who knows that it is only available in that room. The principle behind the latter method is Zero-knowledge Proof.
Zero-knowledge Proof is proving that one knows the password without conveying any other information. This effectively solves many verification related problems.