Everything provable is provable in zero-knowledge

Abstract

Assuming the existence of a secure probabilistic encryption scheme, we show that every language that admits an interactive proof admits a (computational) zero-knowledge interactive proof. This result extends the result of Goldreich, Micali and Wigderson, that, under the same assumption, all of NP admits zero-knowledge interactive proofs. Assuming envelopes for bit commitment, we show tht every language that admits an interactive proof admits a perfect zero-knowledge interactive proof.