Knowledge extraction is a fundamental notion, modeling knowledge possession in a computational complexity sense. The notion provides a tool for cryptographic protocol design and analysis, enabling one to argue about the internal state of protocol players. We define and
investigate the relative power of the notion of ``concurrent knowledge-extraction'' ... more >>>

In this work, we present a generic yet practical transformation from any public-coin honest-verifier zero-knowledge (HVZK) protocols to normal zero-knowledge (ZK) arguments. By ``generic", we mean that the transformation is applicable to any public-coin HVZK protocol under any one-way function (OWF) admitting Sigma-protocols. By ``practical" we mean that the transformation ... more >>>

We present constant-round concurrently secure (sound) resettable
zero-knowledge (rZK-CS) arguments in the bare public-key (BPK)
model. Our constructions deal with general NP ZK-arguments as well
as with highly efficient ZK-arguments for number-theoretic
languages, most relevant to identification scenarios. These are the
first constant-round protocols of ... more >>>