|Author||Dwork, Cynthia ♦ Naor, Moni ♦ Reingold, Omer ♦ Stockmeyer, Larry|
|Source||ACM Digital Library|
|Publisher||Association for Computing Machinery (ACM)|
|Subject Domain (in DDC)||Computer science, information & general works ♦ Data processing & computer science|
|Subject Keyword||Digital signature ♦ Fiat-Shamir methodology ♦ Interactive argument ♦ Interactive proof system ♦ Magic function ♦ Selective decommitment ♦ Zero knowledge|
|Abstract||We prove that three apparently unrelated fundamental problems in distributed computing, cryptography, and complexity theory, are essentially the same problem. These three problems and brief descriptions of them follow. (1) The selective decommitment problem. An adversary is given commitments to a collection of messages, and the adversary can ask for some subset of the commitments to be opened. The question is whether seeing the decommitments to these open plaintexts allows the adversary to learn something unexpected about the plaintexts that are unopened. (2) The power of 3-round weak zero-knowledge arguments. The question is what can be proved in (a possibly weakened form of) zero-knowledge in a 3-round argument. In particular, is there a language outside of BPP that has a 3-round public-coin weak zero-knowledge argument? (3) The Fiat-Shamir methodology. This is a method for converting a 3-round public-coin argument (viewed as an identification scheme) to a 1-round signature scheme. The method requires what we call a "magic function" that the signer applies to the first-round message of the argument to obtain a second-round message (queries from the verifier). An open question here is whether every 3-round public-coin argument for a language outside of BPP has a magic function.It follows easily from definitions that if a 3-round public-coin argument system is zero-knowledge in the standard (fairly strong) sense, then it has no magic function. We define a weakening of zero-knowledge such that zero-knowledge ⇒ no-magic-function still holds. For this weakened form of zero-knowledge, we give a partial converse: informally, if a 3-round public-coin argument system is not weakly zero-knowledge, then some form of magic is possible for this argument system. We obtain our definition of weak zero-knowledge by a sequence of weakenings of the standard definition, forming a hierarchy. Intermediate forms of zero-knowledge in this hierarchy are reasonable ones, and they may be useful in applications. Finally, we relate the selective decommitment problem to public-coin proof systems and arguments at an intermediate level of the hierarchy, and obtain several positive security results for selective decommitment.|
|Age Range||18 to 22 years ♦ above 22 year|
|Education Level||UG and PG|
|Learning Resource Type||Article|
|Publisher Place||New York|
|Journal||Journal of the ACM (JACM)|
Ministry of Human Resource Development (MHRD) under its National Mission on Education through Information and Communication Technology (NMEICT) has initiated the National Digital Library of India (NDLI) project to develop a framework of virtual repository of learning resources with a single-window search facility. Filtered and federated searching is employed to facilitate focused searching so that learners can find out the right resource with least effort and in minimum time. NDLI is designed to hold content of any language and provides interface support for leading vernacular languages, (currently Hindi, Bengali and several other languages are available). It is designed to provide support for all academic levels including researchers and life-long learners, all disciplines, all popular forms of access devices and differently-abled learners. It is being developed to help students to prepare for entrance and competitive examinations, to enable people to learn and prepare from best practices from all over the world and to facilitate researchers to perform inter-linked exploration from multiple sources. It is being developed at Indian Institute of Technology Kharagpur.
NDLI is a conglomeration of freely available or institutionally contributed or donated or publisher managed contents. Almost all these contents are hosted and accessed from respective sources. The responsibility for authenticity, relevance, completeness, accuracy, reliability and suitability of these contents rests with the respective organization and NDLI has no responsibility or liability for these. Every effort is made to keep the NDLI portal up and running smoothly unless there are some unavoidable technical issues.
Ministry of Human Resource Development (MHRD), through its National Mission on Education through Information and Communication Technology (NMEICT), has sponsored and funded the National Digital Library of India (NDLI) project.
For any issue or feedback, please write to email@example.com