Proof-of-Stake Longest Chain Protocols: Security vs Predictability
Abstract
The Nakamoto longest chain protocol is remarkably simple and has been proven to provide security against any adversary with less than 50% of the total hashing power. Proof-of-stake (PoS) protocols are an energy efficient alternative; however existing protocols adopting Nakamoto's longest chain design achieve provable security only by allowing long-term predictability (which have serious security implications). In this paper, we prove that a natural longest chain PoS protocol with similar predictability as Nakamoto's PoW protocol can achieve security against any adversary with less than 1/(1+e) fraction of the total stake. Moreover we propose a new family of longest chain PoS protocols that achieve security against a 50% adversary, while only requiring short-term predictability. Our proofs present a new approach to analyzing the formal security of blockchains, based on a notion of adversary-proof convergence.
Cite
@article{arxiv.1910.02218,
title = {Proof-of-Stake Longest Chain Protocols: Security vs Predictability},
author = {Vivek Bagaria and Amir Dembo and Sreeram Kannan and Sewoong Oh and David Tse and Pramod Viswanath and Xuechao Wang and Ofer Zeitouni},
journal= {arXiv preprint arXiv:1910.02218},
year = {2020}
}
Comments
65 pages, 16 figures