Proof-of-stake longest chain protocols: security vs predicability

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, subjecting the system to serious bribery attacks. In this thesis, we prove that a natural longest chain PoS protocol with predictability similar to that of 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 Nakamoto block.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Electrical & Computer Engr

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2021

Author dc:creator

• Wang, Xuechao

Contributors dc:contributor

• Viswanath, Pramod

• Blockchain
• Proof-of-stake

Statement dc:rights

• Copyright 2020 Xuechao Wang

Language dc:language

en

Handle dc:identifier

http://hdl.handle.net/2142/109360

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/109360