Ouroboros: A Provably Secure Proof-of-Stake Blockchain Protocol

Cardano Blockchain currently runs Ouroboros Praos version of Ouroboros series of Proof of Stake consensus protocols, this version of Ouroboros uses Verifiable Random Function in order to hide the identity of next block-producer, which brings it's own issues, however, Ouroboros Omega is being planned as an upgrade for the Cardano consensus protocol, incorporating ideas from Ouroboros Genesis and Ouroboros Chronos.

Ouroboros Proof of Stake Research Papers