On the Composition of Public-Coin Zero-Knowledge Protocols
Abstract
We show that only languages in BPP have public-coin black-box zero-knowledge protocols that are secure under an unbounded (polynomial) number of parallel repetitions. This result holds both in the plain model (without any set-up) and in the Bare Public-Key Model (where the prover and the verifier have registered public keys). We complement this result by constructing a public-coin black-box zero-knowledge proof based on one-way functions that remains secure under any a-priori bounded number of concurrent executions. A key step (of independent interest) in the analysis of our lower bound shows that any public coin protocol, when repeated sufficiently in parallel, satisfies a notion of "resettable soundness" if the verifier picks its random coins using a pseudorandom function.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 31, 2011
- Accession Number
- ADA582593
Entities
People
- Douglas Wikstroem
- Rafael Pass
- Wei-lung D. Tseng
Organizations
- Cornell University