Weighted Voting on the Blockchain: Improving Consensus in Proof of Stake Protocols. (arXiv:1903.04213v4 [cs.GT] UPDATED)

Proof of Stake (PoS) protocols rely on voting mechanisms to reach consensus
on the current state. If an enhanced majority of staking nodes, also called
validators, agree on a proposed block, then this block is appended to the
blockchain. Yet, these protocols remain vulnerable to faults caused by
validators who abstain either accidentally or maliciously. To protect against
such faults while retaining the PoS selection and reward allocation schemes, we
study weighted voting in validator committees. We formalize the block creation
process and introduce validators’ voting profiles which we update by a
multiplicative weights algorithm relative to validators’ voting behavior and
aggregate blockchain rewards. Using this framework, we leverage weighted
majority voting rules that optimize collective decision making to show, both
numerically and analytically, that the consensus mechanism is more robust if
validators’ votes are appropriately scaled. We raise potential issues and
limitations of weighted voting in trustless, decentralized networks and relate
our results to the design of current PoS protocols.