A Formally Verified Protocol for Log Replication with Byzantine Fault Tolerance


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Date

2020

Publication Type

Conference Paper

ETH Bibliography

yes

Citations

Altmetric

Data

Abstract

Byzantine fault tolerant protocols enable state replication in the presence of crashed, malfunctioning, or actively malicious processes. Designing such protocols without the assistance of verification tools, however, is remarkably error-prone. In an adversarial environment, performance and flexibility come at the cost of complexity, making the verification of existing protocols extremely difficult. We take a different approach and propose a formally verified consensus protocol designed for a specific use case: secure logging. Our protocol allows each node to propose entries in a parallel subroutine, and guarantees that correct nodes agree on the set of all proposed entries, without leader election. It is simple yet practical, as it can accommodate the workload of a logging system such as Certificate Transparency. We show that it is optimal in terms of both required rounds and tolerable faults. Using Isabelle/HOL, we provide a fully machine-checked security proof based upon the Heard-Of model, which we extend to support signatures. We also present and evaluate a prototype implementation.

Publication status

published

Editor

Book title

2020 International Symposium on Reliable Distributed Systems (SRDS)

Journal / series

Volume

Pages / Article No.

101 - 112

Publisher

IEEE

Event

39th International Symposium on Reliable Distributed Systems (SRDS 2020) (virtual)

Edition / version

Methods

Software

Geographic location

Date collected

Date created

Subject

Byzantine fault tolerant; Consensus algorithms; Formal verification

Organisational unit

03975 - Perrig, Adrian / Perrig, Adrian check_circle

Notes

Due to the Coronavirus (COVID-19) the conference was conducted virtually.

Funding

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