R3V: Robust Round Robin VDF-based Consensus

Abstract

Proof of Stake (PoS) based consensus provides a better mechanism than Proof of Work (PoW) consensus for extending the blockchain without significant energy waste. Most of the PoS consensus protocols derive or use some randomness to elect a leader candidate. This makes the consensus weaker and attracts more attackers to mount different attacks, e.g., long-range attacks and block withholding attacks. In PoS consensus, having more stakes gives more chances to be a leader among participating stakeholders. Therefore, most PoS protocols do not provide better fairness for the stakeholders participating in the consensus protocol. Moreover, these protocols suffer from high communication complexity for selecting a leader candidate in each consensus round. In this work, we propose a novel consensus protocol “R3V” that selects a set of leader candidates in a round-robin manner according to age. Finally, these leader candidates compete to be the block leader by solving a Verifiable Delay Function (VDF) based puzzle. We propose different methods to generate verifiable identities for the stakeholders. The identities are enrolled in the blockchain, which provides the age norm needed for the consensus. Compared with the other PoS consensus protocols, our protocol shows better resilience against most of the common attacks on PoS protocols. Additionally, it proclaims low energy consumption, less communication complexity, and better fairness.