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'' (CKE) ... 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 this type in the original ... more >>>

We investigate the decoding problem of Reed-Solomon Codes (aka: the Polynomial Reconstruction Problem -- PR) from a cryptographic hardness perspective. First, following the standard methodology for constructing cryptographically strong primitives, we formulate a decisional intractability assumption related to the PR problem. Then, based on this assumption we show: (i) hardness ... more >>>