Loosely speaking, zero-knowledge interactive-proofs allow one player (called the Prover) to convince another player (the Verifier) of the validity of a mathematical statement, while providing zero additional knowledge to the Verifier. This is formalized by requiring that the view of every "efficient" verifier can be "efficiently" simulated. An outstanding open question regarding zero-knowledge is whether constant-round concurrent zero-knowledge proofs exist for non-trivial languages. We answer this question in the affirmative when modeling "efficient adversaries" as probabilistic *quasi-polynomial* time machines (instead of the traditional notion of probabilistic polynomial-time machines).
In this talk, I will give a brief introduction on zero-knowledge and concurrency and then present our result. The talk will be self contained.
This is joint work with Rafael Pass. Appeared in Theory of Cryptography Conference (TCC 2008).