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Cited by 284Blockchain Technology Applications and SecurityBlockchain Technology in Education and LearningDistributed systems and fault tolerance

The DOI matches its Crossref record; 99 of the 108 references it cites were found in a registry or an index; none of the 97 sources its claims cite is checked for support yet.

A Review of Blockchain Architecture and Consensus Protocols: Use Cases, Challenges, and Solutions

Open access
Ismail, Leila, Materwala, Huned·2019·Symmetry
DOI 10.3390/sym11101198

Published version of a preprint

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Abstract

Over the last decade, blockchain technology has emerged to provide solutions to the complexity and privacy challenges of using distributed databases. It reduces cost for customers by eliminating intermediaries and builds trust in peer-to-peer communications. Over this time, the concept of blockchain has shifted greatly due to its potential in business growth for enterprises and the rapidly evolving applications in a collaborative smart-city ecosystem, healthcare, and governance. Many platforms, with different architectures and consensus protocols, have been introduced. Consequently, it becomes challenging for an application developer to choose the right platform. Furthermore, blockchain has misaligned with the goals for an efficient green collaborative digital ecosystem. Therefore, it becomes critical to address this gap and to build new frameworks to align blockchain with those goals. In this paper, we discuss the evolution of blockchain architecture and consensus protocols, bringing a retrospective analysis and discussing the rationale of the evolution of the various architectures and protocols, as well as capturing the assumptions conducive to their development and contributions to building collaborative applications. We introduce a classification of those architectures helping developers to choose a suitable platform for applications and providing insights for future research directions in the field to build new frameworks.

Overview

AI snapshot

Written from the paper’s full text.

TL;DR

This review surveys the evolution of blockchain architecture and consensus protocols, classifying platforms into single-ledger public/private/hybrid, multi-ledger private, and interoperability architectures, and consensus into compute-intensive, capability-based, and voting-based categories. It maps use cases and challenges, arguing that current designs misalign with scalable, green collaborative ecosystems and proposing directions for future frameworks.

Key findings

  • The paper presents a taxonomy of blockchain architectures and 21 consensus protocols, claiming to be the first detailed systematic survey with such a platform-architecture and consensus-protocol taxonomy.
  • Energy use is a central concern: 2017 bitcoin mining used about 30.14 TWh, equivalent to Ireland’s annual energy use; annual bitcoin CO₂ emissions are reported as high as 22.9 million metric tons; and annual energy consumption as of 22 June 2019 is 67.937 TWh.
  • PoW-based bitcoin throughput is reported as 4–7 transactions per second, while Gervais et al. showed PoW-based blockchain throughput can increase up to 60 transactions per second at the same security level.
  • Voting-based protocols such as PBFT improve throughput over PoW but require authority for leader/backup selection; FBA requires 80% agreement versus 66% in PBFT, and PBFT tolerates fewer than n/3 malicious or crashed nodes.

Methods

  • Design: a review/survey synthesizing blockchain architecture, consensus protocols, platforms, and applications, with retrospective temporal analysis.
  • Data: literature, existing blockchain platforms, consensus protocols, and application examples; no primary experimental dataset is collected.
  • Analysis: classification/taxonomy and comparison, including tables comparing public vs. private networks and mapping development platforms to architecture types.

Limitations

  • Stated: few consensus protocols have been evaluated for performance and security threats; evaluations use different experimental environments and setups, and no work compares all consensus algorithms in a unified experimental environment.
  • Stated: many proposed scalability and energy-efficiency solutions are still under development and not tested across existing blockchain networks; several consensus protocols have not been tested for performance or protection against security threats.
  • Evident from the text: despite being called a systematic survey, no search strategy, inclusion criteria, or systematic review protocol is described; the review also relies heavily on white papers, websites, and platform documentation.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.3390/sym11101198

Cites

99 of 99 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Verification

Claims the paper makes

0 of 97 cited sources checked · 0 supported · 0 flagged

Show all 95 claims

  • Probably not a substantial claim. 128
  • It may state two separate claims as one. 75
168 of 168

  • The paper relies on this without support.

    Addressing energy consumption and scalability problems often trades off with security and privacy.

    “Addressing these problems of energy consumption and scalability often trades off with security, and privacy.”

  • The paper relies on this without support.

    Growing business requires trust and transparency between customers and business providers.

    “Growing business requires trust and transparency between the customers and business providers.”

  • The paper relies on this without support.

    Customers require eliminating intermediaries to reduce transaction costs.

    “Customers require to eliminate intermediaries to reduce transactions cost.”

  • The paper relies on this without support.

    Data communication overhead increases with the number of network participants and hinders real-time services of developed applications.

    “The issues of data communication overhead with increasing number of network participants further hinders the real-time services of the developed applications.”

  • The paper relies on this without support.

    The rapid adoption of blockchain by different application domains motivated the development of many blockchain platforms.

    “The rapid adoption of blockchain by different applications domains motivated the development of many blockchain platforms.”

  • The paper relies on this without support.

    There is a gap between existing consensus algorithms and applications' needs in terms of scalability, complexity, cost effectiveness, and energy efficiency.

    “However, there prevails a gap between the existing algorithms and the applications' needs in terms of scalability, complexity, cost effectiveness, and energy efficiency.”

  • The paper relies on this without support.

    The increasing amount of energy consumption is affecting the environment with increasing global warming.

    “This increasing amount of energy consumption is affecting the environment with increasing global warming.”

  • The paper relies on this without support.

    The price of digital currency is increasing compared to computing hardware capacity.

    “This is because of the increasing price of digital currency (required in PoS) as compared to the computing hardware capacity (required in PoW).”

  • The paper relies on this without support.

    The economy benefits from financial flow.

    “to prevent the financial flow in the system, which is necessary for an economy to grow.”

  • The paper relies on this without support.

    A blockchain network is not controlled by any single authority.

    “Because a blockchain network is not controlled by any single authority”

  • The authors state this as an assumption.

    In the PoET z-test, each node has the same winning probability p, and the number of wins follows a normal distribution N(mp, mp(1-p)).

    “The test assumes that if the network has 'm' nodes, then each node has the same winning probability 'p', with the number of wins following a normal distribution N(mp, mp(1p)).”

  • The authors state this as an assumption.

    In PBFT, all honest nodes have an exact same copy of the ledger.

    “All nodes in the system communicates with each other with the goal of reaching to an agreement by assuming that all honest nodes will have a exact same copy of the ledger.”

  • The authors state this as an assumption.

    In voting-based consensus protocols, there are independent node failures in the network or some nodes behave maliciously.

    “These protocols are designed to tolerate byzantine faults by assuming that there are independent node failures in the network or some of the nodes will behave maliciously.”

  • The paper relies on this without support.

    Applications' needs are continuously evolving in a collaborative ecosystem such as smart cities, social networking, governance, and smart healthcare, with the ultimate goals of green computing and cost reduction.

    “This is due to the continuously evolving applications' needs in a collaborative ecosystem such as smart cities, social networking, governance, and smart heatlhcare with the ultimate goals of green computing and cost reduction.”
14 of 14

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

  • Proof-of-stake penalties are described oppositely

    Major

    The paper first says a malicious forger loses its staked coins, then says malicious users can generate invalid blocks because their staked coins are returned.

  • Proof-of-space hash iterations end at two different counts

    Minor

    The plotting procedure says its remaining iterations run through 8912, but the same description says that only 8192 hashes are generated.

  • Oracle citation points to a Credits reference

    Minor

    The cited reference [54] is listed as a Credits white paper, not an Oracle source.

  • An incorrect world-state output is classified as valid

    Minor

    The multi-ledger execution steps include a transaction with an incorrect world-state output in the block of valid transactions, but then say invalid transactions are excluded from that block.

  • Proof of Activity is called Proof of Authority

    Minor

    The section heading names the PoW-plus-PoS protocol Proof of Activity, while its description calls that same protocol Proof of Authority. The paper separately uses Proof of Authority for a reputation-based protocol.

5 of 5

Citations

Cites

Flagged first, then by citations

9 of the 108 references couldn’t be matched to a known paper.

Research works printed but not linked: 10

  1. Ahamad, S., Nair, M., and Varghese, B. (2013, January 13–14). A survey on crypto currencies. Proceedings of the 4th International Conference on Advances in Computer Science, AETACS, NCR, India.
  2. Nguyen, 2018, A survey about consensus algorithms used in Blockchain, J. Inf. Process. Syst., 14, 101
  3. Szabo, 1996, Smart contracts: Building blocks for digital markets, Extropy J. Transhumanist Thought, 18, 2
  4. King, 2013, Primecoin: Cryptocurrency with prime number proof-of-work, July 7th, 1, 6
  5. Ribenboim, P. (2012). The New Book of Prime Number Records, Springer Science & Business Media.
  6. Chen, L., Xu, L., Shah, N., Gao, Z., Lu, Y., and Shi, W. (2017, January 5–8). On security analysis of proof-of-elapsed-time (poet). Proceedings of the International Symposium on Stabilization, Safety, and Security of Distributed Systems, Boston, MA, USA. · DOI · Paper page
  7. Kwon, 2014, Tendermint: Consensus without mining, Draft v. 0.6, fall, 1, 11
  8. (2018, December 19). IBM News Room—2017-08-09 Sony and Sony Global Education Develop a New System to Manage Students’ Learning Data, Built on IBM Blockchain—United States. Available online: https://www-03.ibm.com/press/us/en/pressrelease/52970.wss.
  9. Pichel, 2016, Blockchain for land administration, GIM Int., 30, 38
  10. Panesir, M.S. (2018). Blockchain Applications for Disaster Management and National Security. [Ph.D. Thesis, State University of New York at Buffalo].

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Metadata

Authors
Ismail, L., & Materwala, H.
Affiliations
United Arab Emirates University (AE)
Corresponding author
Ismail, Leila
ORCID
Venue
Symmetry
Publisher
MDPI AG
Published
2019-09-24
Volume
11
Issue
10
Pages
1198
ISSN
2073-8994 (ISSN-L)
DOI
10.3390/sym11101198
OpenAlex
W2970755484
Semantic Scholar
4358f24ea5968eede3fffc4ce73d6b1ddeb9b470
Cited by
278
References
108
Citations by year
2026: 13 · 2025: 34 · 2024: 48 · 2023: 67 · 2022: 52 · 2021: 39 · 2020: 21 · 2019: 4
FWCI
36.11
Type
journal article
Language
en
Open access
Licence
Locations
  • Symmetry (publishedVersion, cc-by)
  • Preprints.org (acceptedVersion, cc-by)
  • DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion, cc-by-sa)
Funders
United Arab Emirates University (31R101)
Topics
  • Physical Sciences › Computer Science › Information Systems › Blockchain Technology Applications and Security
  • Physical Sciences › Computer Science › Information Systems › Blockchain Technology in Education and Learning
  • Physical Sciences › Computer Science › Computer Networks and Communications › Distributed systems and fault tolerance
Keywords
blockchain architecture, consensus algorithms, blockchain platform selection, distributed databases, peer-to-peer trust, smart cities, blockchain in healthcare, blockchain governance

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