An improved parallel interactive Feige-Fiat-Shamir identification scheme with almost zero soundness error and complete zero-knowledge

Zero-knowledge protocols are used in some real-world applications where lighter computation and no encryption are required, for instance, securing smart card. Feige-Fiat-Shamir is one of the well-known ZKP identification schemes. However some of its security problems are the zero-knowledge not closed under parallel execution and its negligible soundness error (2-kt). Although computationally secure, this error may become significant with future advanced technology. In this paper we present an improved 3-pass parallel interactive scheme with `almost' zero soundness error and complete zero-knowledge. This new scheme is based on Feige-Fiat-Shamir digital signature.