Alternative variants of zero-knowledge proofs
Rafael Pass · 2004
Zero-knowledge proofs are one of the most important cryptographic notions. Since their introduction in the early 80's by Goldwasser, Micali and Racko, they have proven very useful in the design of cryptographic protocols. Nevertheless, many limitations (in terms of e ciency and robustness under concurrent executability of protocols) have also been noticed. In order to overcome these limitations two lines of research have been investigated in the literature: 1. Models with some limited intervention of a trusted party (for example during a set-up phase). 2. Weakenings of the notion of zero-knowledge. In this thesis we attempt to further the understanding of the notion of zero-knowledge proofs by addressing both the above lines of research. More precisely, 1. Concerning the rst line of research, we show that the de nition of zeroknowledge in certain popular models (namely the Common Reference