Notebook of Zero-Knowledge Proof

Theoritical Examples

1. There is a cave with two corridors which connects to each other at their ends, divided by a door which is locked. Only Peggy knows the password but doesn’t want to reveal it and has to prove that she knows it. So Victor asks Peggy to choose one any corridor she likes to enter but returns from the one that Victor chooses. That means any corridor Peggy enters must be able to come back from both. If Victor chooses the one she didin’t enter than she has to unlock the door at back and pass to the other corridor to get out from the one that Victor asked. Victor and Peggy replays the scenario several times and everytime Peggy could come out that convince the Victor that Peggy knows the secret of the door without giving it to Victor.