Reaching consensus for asynchronous distributed key generation

We give a protocol for Asynchronous Distributed Key Generation (A-DKG) that is optimally resilient (can withstand $${{\varvec{f}}}<\frac{{{\varvec{n}}}}{{{\varvec{3}}}}$$ faulty parties), has constant expected number of rounds, $${{\varvec{O}}}({\varvec{\lambda }} {{\varvec{n}}}^{{\varvec{3}}})$$ communication complexity, and assumes only the existence PKI. Prior to our work, best A-DKG protocols required $${\varvec{\Omega }}({{\varvec{n}}})$$ }}({{\varvec{n}}}^4)$$ communication. Our relies on several building blocks are independent interest. define design Proposal Election (PE) allows parties retrospectively agree valid proposal after enough proposals have been sent from different parties. With probability elected was proposed by nonfaulty party. In PE protocol, we Verifiable Gather which communicate they not seen in verifiable manner. The final block Validated Byzantine Agreement (VABA) protocol. use construct VABA does require leaders or an asynchronous DKG setup. can be used more generally when it possible threshold signatures.