分野別セミナー

Verifiable secret sharing (VSS) allows honest parties to ensure consistency of their shares even if a dealer and/or a subset of parties are corrupt. We focus on perfect VSS, i.e., those providing perfect privacy, correctness and commitment with zero error, in the unconditional (information-theoretic) security setting where no assumption on the computational power of the participants is imposed.
To motivate our study, we consider a scenario where the dealer uses a mobile device such that connection problems and performance restrictions limit her capability for interaction and generation of good randomness. We call such a scenario {\em VSS with non-interactive dealer}. So, the parties are able to verify consistency of their shares by themselves.
We present such protocols tolerating $Q^3$ active adversaries for general and threshold adversaries. Since the errors created by the active adversaries can be regarded as forming a tensor, we link our approach with Tensor Codes.