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PBFT vs proof-of-authority: applying the CAP theorem to permissioned blockchain

PBFT vs proof-of-authority: applying the CAP theorem to permissioned blockchain
PBFT vs proof-of-authority: applying the CAP theorem to permissioned blockchain
Permissioned blockchains are arising as a solution to federate companies prompting accountable interactions. A variety of consensus algorithms for such blockchains have been proposed, each of which has different benefits and drawbacks. Proof-of-Authority (PoA) is a new family of Byzantine fault-tolerant (BFT) consensus algorithms largely used in practice to ensure better performance than traditional Practical Byzantine Fault Tolerance (PBFT). However, the lack of adequate analysis of PoA hinders any cautious evaluation of their effectiveness in real-world permissioned blockchains deployed over the Internet, hence on an eventually synchronous network experimenting Byzantine nodes.
In this paper, we analyse two of the main PoA algorithms, named Aura and Clique, both in terms of provided guarantees and performances. First, we derive their functioning including how messages are exchanged, then we weight, by relying on the CAP theorem, consistency, availability and partition tolerance guarantees. We also report a qualitative latency analysis based on message rounds. The analysis advocates that PoA for per- missioned blockchains, deployed over the Internet with Byzantine nodes, do not provide adequate consistency guarantees for scenarios where data integrity is essential. We claim that PBFT can fit better such scenarios, despite a limited loss in terms of performance.
De Angelis, Stefano
3a260021-da00-4b26-b9f0-b91dcf70cb19
Aniello, Leonardo
9846e2e4-1303-4b8b-9092-5d8e9bb514c3
Baldoni, Roberto
4265db45-a184-45c4-a56d-b5829b6f6f1f
Lombardi, Federico
78e41297-64c9-4c1e-9515-8eb59334a795
Margheri, Andrea
4b87c32d-3eaf-445e-8ac0-8207daace2e1
Sassone, Vladimiro
df7d3c83-2aa0-4571-be94-9473b07b03e7
De Angelis, Stefano
3a260021-da00-4b26-b9f0-b91dcf70cb19
Aniello, Leonardo
9846e2e4-1303-4b8b-9092-5d8e9bb514c3
Baldoni, Roberto
4265db45-a184-45c4-a56d-b5829b6f6f1f
Lombardi, Federico
78e41297-64c9-4c1e-9515-8eb59334a795
Margheri, Andrea
4b87c32d-3eaf-445e-8ac0-8207daace2e1
Sassone, Vladimiro
df7d3c83-2aa0-4571-be94-9473b07b03e7

De Angelis, Stefano, Aniello, Leonardo, Baldoni, Roberto, Lombardi, Federico, Margheri, Andrea and Sassone, Vladimiro (2018) PBFT vs proof-of-authority: applying the CAP theorem to permissioned blockchain. Italian Conference on Cyber Security. 11 pp.

Record type: Conference or Workshop Item (Paper)

Abstract

Permissioned blockchains are arising as a solution to federate companies prompting accountable interactions. A variety of consensus algorithms for such blockchains have been proposed, each of which has different benefits and drawbacks. Proof-of-Authority (PoA) is a new family of Byzantine fault-tolerant (BFT) consensus algorithms largely used in practice to ensure better performance than traditional Practical Byzantine Fault Tolerance (PBFT). However, the lack of adequate analysis of PoA hinders any cautious evaluation of their effectiveness in real-world permissioned blockchains deployed over the Internet, hence on an eventually synchronous network experimenting Byzantine nodes.
In this paper, we analyse two of the main PoA algorithms, named Aura and Clique, both in terms of provided guarantees and performances. First, we derive their functioning including how messages are exchanged, then we weight, by relying on the CAP theorem, consistency, availability and partition tolerance guarantees. We also report a qualitative latency analysis based on message rounds. The analysis advocates that PoA for per- missioned blockchains, deployed over the Internet with Byzantine nodes, do not provide adequate consistency guarantees for scenarios where data integrity is essential. We claim that PBFT can fit better such scenarios, despite a limited loss in terms of performance.

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Accepted/In Press date: 2017
Published date: January 2018
Venue - Dates: Italian Conference on Cyber Security, 2018-02-06

Identifiers

Local EPrints ID: 415083
URI: https://eprints.soton.ac.uk/id/eprint/415083
PURE UUID: 1bc8c30c-b80e-40c2-9810-a56815582308
ORCID for Stefano De Angelis: ORCID iD orcid.org/0000-0002-1168-9064
ORCID for Federico Lombardi: ORCID iD orcid.org/0000-0001-6463-8722
ORCID for Andrea Margheri: ORCID iD orcid.org/0000-0002-5048-8070

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Date deposited: 25 Oct 2017 16:30
Last modified: 06 Jun 2018 12:23

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Contributors

Author: Stefano De Angelis ORCID iD
Author: Leonardo Aniello
Author: Roberto Baldoni
Author: Federico Lombardi ORCID iD
Author: Andrea Margheri ORCID iD
Author: Vladimiro Sassone

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