Zero-knowledge password proof

Zero-knowledge password proof is a way of confirming that you know something without actually telling the person or computer what it is. It's a bit like playing a guessing game. For example, let's say you have a secret password and someone asks you to prove that you know it. With zero-knowledge password proof, you might give the person or computer three hints: hints about the letters in the password, the length of the password, and the first letter of the password. With these hints, the person or computer can test your knowledge without you having to tell them your secret password.