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Electronic Colloquium on Computational Complexity

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All reports by Author Shien Jin Ong:

TR06-139 | 14th November 2006
Shien Jin Ong, Salil Vadhan

Zero Knowledge and Soundness are Symmetric

Revisions: 1

We give a complexity-theoretic characterization of the class of problems in NP having zero-knowledge argument systems that is symmetric in its treatment of the zero knowledge and the soundness conditions. From this, we deduce that the class of problems in NP intersect coNP having zero-knowledge arguments is closed under complement. ... more >>>

TR06-075 | 19th June 2006
Minh-Huyen Nguyen, Shien Jin Ong, Salil Vadhan

Statistical Zero-Knowledge Arguments for NP from Any One-Way Function

We show that every language in NP has a *statistical* zero-knowledge
argument system under the (minimal) complexity assumption that
one-way functions exist. In such protocols, even a computationally
unbounded verifier cannot learn anything other than the fact that the
assertion being proven is true, whereas a polynomial-time prover
cannot convince ... more >>>

TR05-114 | 9th October 2005
Boaz Barak, Shien Jin Ong, Salil Vadhan

Derandomization in Cryptography

We give two applications of Nisan--Wigderson-type ("non-cryptographic") pseudorandom generators in cryptography. Specifically, assuming the existence of an appropriate NW-type generator, we construct:

A one-message witness-indistinguishable proof system for every language in NP, based on any trapdoor permutation. This proof system does not assume a shared random string or any ... more >>>

TR05-093 | 24th August 2005
Daniele Micciancio, Shien Jin Ong, Amit Sahai, Salil Vadhan

Concurrent Zero Knowledge without Complexity Assumptions

We provide <i>unconditional</i> constructions of <i>concurrent</i>
statistical zero-knowledge proofs for a variety of non-trivial
problems (not known to have probabilistic polynomial-time
algorithms). The problems include Graph Isomorphism, Graph
Nonisomorphism, Quadratic Residuosity, Quadratic Nonresiduosity, a
restricted version of Statistical Difference, and approximate
versions of the (<b>coNP</b> forms of the) Shortest Vector ... more >>>

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