© 2006

Concurrent Zero-Knowledge

With Additional Background by Oded Goldreich


Part of the Information Security and Cryptography book series (ISC)

About this book


Zero-knowledge proofs are fascinating and extremely useful constructs. Their fascinating nature is due to their seemingly contradictory de?nition; ze- knowledge proofs are convincing and yet yield nothing beyond the validity of the assertion being proved. Their applicability in the domain of cryptography is vast; they are typically used to force malicious parties to behave according to a predetermined protocol. In addition to their direct applicability in cr- tography, zero-knowledge proofs serve as a good benchmark for the study of variousproblemsregardingcryptographicprotocols(e.g.,“securecomposition of protocols”). A fundamental question regarding zero-knowledge protocols refers to the preservation of security (i.e., of the zero-knowledge feature) when many - stances are executed concurrently, and in particular under a purely as- chronous model. The practical importance of this question, in the days of extensive Internet communication, seems clear. It turned out that this qu- tion is also very interesting from a theoretical point of view. In particular, this question served as a benchmark for the study of the security of concurrent executions of protocols and led to the development of techniques for coping with the problems that arise in that setting.


Black-box simulation Concurrent zero-knowledge Protocol security Zero-knowledge Zero-knowledge proof systems algorithms communication cryptography

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  1. 1.Harvard University DEASCambridgeUSA

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From the reviews:

"Protocols that remain zero-knowledge when many instances are executed concurrently are called concurrent zero-knowledge. This book is very well suited for the reader who wants to know the state of the art of concurrent zero-knowledge proofs. … The book could be used as a textbook on advanced topics in cryptography. It is highly recommended to the newcomer in the field who wants technical information, and to the researcher in the area who would like a survey on concurrent zero-knowledge." (Yongge Wang, Mathematical Reviews, Issue 2007 m)