This paper introduces the concept of interactive proofs of knowledge, extending the notion of interactive proofs of assertions to demonstrate that a prover possesses knowledge without revealing any computational information. The authors define unrestricted input zero-knowledge proofs of knowledge, where the prover demonstrates knowledge without revealing even a single bit of information. These proofs are relevant to identification schemes, where parties prove their identity by demonstrating knowledge rather than proving the validity of assertions. The authors describe a novel identification scheme that is provably secure if factoring is difficult and is significantly faster than RSA-based schemes. The advantages of thinking in terms of proofs of knowledge are demonstrated in two efficient variants of the scheme: one that requires no directory and another based on parallel interactive proofs, which are not known to be zero knowledge but are proved secure by observing that identification protocols are proofs of knowledge. The paper also discusses the importance of unrestricted input zero-knowledge proofs in identification schemes, highlighting their ability to ensure privacy and security. The authors present a parallel version of the identification scheme, which retains the completeness and soundness properties of the serial version and is shown to release no useful information. The paper concludes with a discussion of the security of the identification scheme and its practical applications.This paper introduces the concept of interactive proofs of knowledge, extending the notion of interactive proofs of assertions to demonstrate that a prover possesses knowledge without revealing any computational information. The authors define unrestricted input zero-knowledge proofs of knowledge, where the prover demonstrates knowledge without revealing even a single bit of information. These proofs are relevant to identification schemes, where parties prove their identity by demonstrating knowledge rather than proving the validity of assertions. The authors describe a novel identification scheme that is provably secure if factoring is difficult and is significantly faster than RSA-based schemes. The advantages of thinking in terms of proofs of knowledge are demonstrated in two efficient variants of the scheme: one that requires no directory and another based on parallel interactive proofs, which are not known to be zero knowledge but are proved secure by observing that identification protocols are proofs of knowledge. The paper also discusses the importance of unrestricted input zero-knowledge proofs in identification schemes, highlighting their ability to ensure privacy and security. The authors present a parallel version of the identification scheme, which retains the completeness and soundness properties of the serial version and is shown to release no useful information. The paper concludes with a discussion of the security of the identification scheme and its practical applications.