Resettability Problem Recall
What if the Verifier could execute the ID protocol repeatedly reseting the prover to use same randomness?
(e.g. Disconnect the power supply of prover implemented by a Smart Card.)
Observation: Proofs of Knowledge of a secret (by definition) can not be ZK/WI/WH if prover can be reset.
Extractor reset attack discovers the secret.
Thus: Identification Schemes based on POK-paradigm are insecure against reset attacks.