Cryptology ePrint Archive: Report 1999/014
Concurrent Zero-Knowledge is Easy in Practice
Abstract: We show that if any one-way function exists, then 3-round concurrent
zero-knowledge arguments for all NP problems can be built in a model
where a short auxiliary string with a prescribed distribution is
available to the players. We also show that all known efficient
identification schemes using specialized assumptions can be modified
to work in this model with no essential loss of efficiency. We argue
that the assumptions of the model will be satisfied in most practical
scenarios where public key cryptography is used, in particular our
construction works given any secure public key
infrastructure. Finally, we point out that in a model with
preprocessing (and no auxiliary string) proposed earlier, concurrent
zero-knowledge for NP can be based on any one-way function.
Category / Keywords: Concurrent Zero-Knowledge, Protocols, Proofs of knowledge.
Publication Info: Appeared in the THEORY OF CRYPTOGRAPHY LIBRARY and has been included in the ePrint Archive.
Date: received June 16th, 1999. Revised July 28th, 1999.
Contact author: ivan at daimi aau dk
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