Delegated Proof of Stake Consensus with Mobile Voters and Multiple Entry PBFT Voting

Abstract

In this work we combine Delegated Proof of Stake (DPoS) consensus technique with multiple entry Practical Byzantine Fault Tolerant voting in a permissioned blockchain network. Voting is organized in rounds that contain a number of PBFT consensus cycles. Nodes with low stake are forced to leave at the end of current round and may return to a new round when they repurchase the stake tokens, while nodes with sufficient stake may leave the network temporarily at the completion of current round due to mobility. We consider multiple DPoS classes based on node's initial stake and probability of truthful voting, and model their behavior using embedded Markov Chain which corresponds to a Semi Markov Process (SMP). We show that probability of reaching consensus is higher when rounds are shorter and/or there are more nodes in the network. In addition, we find that nodes from higher priority classes are mostly excluded from voting due to their mobility, while those from lower priority classes are excluded more often on account of low stake.