An alternative paradigm to analyze proof-of-stake protocols

In applications that use blockchains, Proof of Stake (PoS) chains have become an attractive alternative to more classical Proof of Work (PoW) chains due to their low transaction latency and cheap hardware requirements. Correct implementations of both types of chains provide security against the “double-spend” attack referenced in the original Bitcoin protocol. However, while PoW chains use cryptographic puzzle “mining” as a mechanism for block extension, PoS chains must utilize alternate methods of proposing blocks. As a result, when it is able to participate, an adversary targeting PoS chains can extend multiple blocks without making sacrifices in the strength of its attack. This extension of multiple blocks allows for the adversary to create forks of non-trivial length, which is not explored in PoW analysis. Such forks allow for additional adversarial strategies, and alter the random walk governing the security of the chain in ways that are difficult to monitor. In this paper, we will present a pair of metrics designed to accurately track the advantage gained by an adversary in a reasonable PoS setting. This pair of metrics, determined by the hidden progress of the adversary against publicly released chains, directly map to the adversary’s ability to remove committed blocks from the chain, and behave naturally in a walk detailing the lifetime of a chain. We offer these metrics for the simplification of further analysis of PoS chains and applications. Finally, we confirm previous results regarding the security of PoS chains. Through an analysis of our metric, we show that, like PoW chains, PoS chains are secure against double-spend attacks except for probability which decays exponentially with respect to chain length.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Computer Science

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2021

Author dc:creator

• Tran, Hung

Contributors dc:contributor

• Ren, Ling

• Blockchain
• Proof of Stake
• Proof of Work
• Double-Spend
• Metric
• Paradigm

Statement dc:rights

• Copyright 2021 Hung Tran

Language dc:language

en

Handle dc:identifier

http://hdl.handle.net/2142/110584

OAI record oai:identifier

https://www.ideals.illinois.edu/oai-pmh?verb=GetRecord&metadataPrefix=etdms&identifier=oai%3Awww.ideals.illinois.edu%3A2142%2F110584