AsianScientist (Jul. 2, 2019) – Researchers at Singapore University of Technology and Design have developed an improved protocol that allows blockchains to reach consensus in a secure way. Their findings were awarded the Best Paper Award at the IEEE International Conference on Blockchain and Cryptocurrency in Seoul, South Korea, held on May 14-17, 2019.
Because they are designed to be resistant to the modification of data, blockchains offer security and privacy benefits sought by banks, governments and corporations. One of the ways that blockchain technology provides such security is through proof of stake (PoS) protocols, which rely on voting mechanisms to reach consensus on the current state of data. If an enhanced majority of staking nodes, also called validators, agree on a proposed block of data, then this block is appended to the blockchain.
However, these protocols remain vulnerable to faults caused by validators who abstain either accidentally or maliciously. In particular, while selecting staking nodes proportionally to their stake to form block-creating committees, current PoS protocols do not guarantee that selected committees will create blocks. This in turn violates the perceived fairness in the distribution of rewards in proportion to the stake of participating nodes.
To protect against such faults while retaining the PoS selection and reward allocation schemes, a team of researchers led by Assistant Professor Georgios Piliouras used weighted voting in validator committees. First, they introduced validators’ voting profiles to quantify the probability that a validator will cast a correct vote based on the validator’s previous contributions to date to the protocol. Then they defined the mathematical framework to apply optimal decision rules in committee voting.
The result is a two-layered scheme in which selection of nodes and allocation of rewards are performed by the underlying PoS mechanism whereas blocks are decided by a weighted majority voting rule. This scheme improves consensus within selected committees by scaling votes according to validators’ profiles without interfering with the PoS execution. Hence, it can be tested, implemented and reverted with minimal cost to existing users, the researchers said.
The article can be found at: Leonardos et al. (2019) Weighted Voting on the Blockchain: Improving Consensus in Proof of Stake Protocols.
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Source: Singapore University of Technology and Design; Photo: Shutterstock.
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