A Zero Knowledge Proofs protocol means: O User1 proves to User2 that he/she knows a secret without User2 knowing the secret. User1 proves to User2 that he/she knows a secret after sending an encrypted copy to User2 using public key of User2. User1 proves to User2 that he/she does not know anything. O User1 proves to User2 that he/she knows a secret after sending an encrypted copy to User2 using a shared secret symmetric key. User1 proves to User2 that he/she knows a secret after sending an encrypted copy to User2 using private key of User2. User1 proves to User2 that he/she knows a secret after sending an signed copy to User2 using private key of User1