Exploring Unfairness on Proof of Authority: Order Manipulation Attacks and Remedies

Wang，Qin1; Li，Rujia2,3; Wang，Qi3; Chen，Shiping4; Xiang，Yang5

10.1145/3488932.3517394

2022-05-30

17th ACM ASIA Conference on Computer and Communications Security 2022 (ACM ASIACCS)

ASIA CCS 2022 - Proceedings of the 2022 ACM Asia Conference on Computer and Communications Security

123-137

MAY 30-JUN 03, 2022

null,Nagasaki,JAPAN

1601 Broadway, 10th Floor, NEW YORK, NY, UNITED STATES

ASSOC COMPUTING MACHINERY

Proof of Authority (PoA) is a type of permissioned consensus algorithm with a fixed committee. PoA has been widely adopted by communities and industries due to its better performance and faster finality. In this paper, we explore the unfairness issue existing in the current PoA implementations. We have investigated 2,500+ in the wild projects and selected 10+ as our main focus (covering Ethereum, Binance smart chain, etc.). We have identified two types of order manipulation attacks to separately break the transaction-level (a.k.a. transaction ordering) and the block-level (sealer position ordering) fairness. Both of them merely rely on honest-but-profitable sealer assumption without modifying original settings. We launch these attacks on the forked branches under an isolated environment and carefully evaluate the attacking scope towards different implementations. To date (as of Nov 2021), the potentially affected PoA market cap can reach up to 681,087 million USD. Besides, we further dive into the source code of selected projects, and accordingly, propose our recommendation for the fix. To the best of knowledge, this work provides the first exploration of the unfairness issue in PoA algorithms.

fairness order manipulation proof of authority

Others

English

EI ; CPCI-S

Shenzhen Fundamental Research Programs[20200925154814002]

Computer Science ; Mathematics ; Telecommunications

Computer Science, Information Systems ; Computer Science, Theory & Methods ; Mathematics, Applied ; Telecommunications

WOS:000937026200011

20222712310662

2-s2.0-85130850536

Scopus

1.Swinburne University of Technology & CSIRO,Data61,Melbourne,Australia
2.University of Birmingham,United Kingdom
3.Southern University of Science and Technology,Shenzhen,China
4.CSIRO,Data61,Sydney,Australia
5.Swinburne University of Technology,Melbourne,Australia

Wang，Qin,Li，Rujia,Wang，Qi,et al. Exploring Unfairness on Proof of Authority: Order Manipulation Attacks and Remedies[C]. 1601 Broadway, 10th Floor, NEW YORK, NY, UNITED STATES:ASSOC COMPUTING MACHINERY,2022:123-137.