Taxonomy of Blockchain Technologies. Principles of Identification and Classification

A comparative study across the most widely known blockchain technologies is conducted with a bottom-up approach. Blockchains are disentangled into building blocks. Each building block is then hierarchically classified in main and subcomponents. Then, alternative layouts for the subcomponents are identified and compared between them. Finally, a taxonomy tree summarises the study and provides a navigation tool across different blockchain architectural configurations.

💡 Research Summary

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The paper addresses the growing heterogeneity of blockchain technologies by proposing a systematic taxonomy that breaks down blockchains into elementary building blocks, classifies them hierarchically, and compares possible design layouts. After a brief historical overview that traces blockchain origins to the convergence of distributed ledgers, public‑key cryptography, Merkle trees, and consensus protocols, the authors argue that the current proliferation of thousands of projects, forks, and novel architectures has created a fragmented landscape. This fragmentation hampers performance benchmarking, security assessment, regulatory compliance, and cross‑industry adoption because there is no common reference architecture.

To tackle this, the authors adopt a bottom‑up methodology. First, they compile a unified glossary of blockchain terminology, drawing from literature and an online database, to eliminate ambiguities. Next, they conduct a comparative study across four major families of blockchain applications: digital currencies, application stacks, asset‑registry platforms, and centric technologies. From this study they identify five primary layers that constitute any blockchain system:

1. Data Layer – structures such as blocks, Merkle trees, and state databases.
2. Consensus Layer – algorithms (Proof‑of‑Work, Proof‑of‑Stake, Byzantine Fault Tolerance, DAG‑based protocols, etc.).
3. Network Layer – peer‑to‑peer topologies, hybrid or hub‑spoke models, and communication protocols.
4. Smart‑Contract Layer – execution environments (EVM, WASM, off‑chain or hybrid execution).
5. Governance Layer – on‑chain voting, off‑chain committees, upgrade mechanisms, and incentive schemes.

Each primary layer is further divided into sub‑components (e.g., cryptographic primitives, node roles, block‑validation rules) and, where appropriate, sub‑sub‑components. For every sub‑component the authors enumerate two to three representative implementation layouts, creating a cross‑matrix that highlights trade‑offs in scalability, security, latency, and regulatory fit. For instance, the Consensus Layer may be realized via PoW (high energy consumption, strong decentralisation), PoS (lower energy, stake‑based influence), or BFT (fast finality but limited node count). The Network Layer can adopt a pure P2P mesh, a permissioned overlay, or a hybrid model that combines public discovery with private data channels.

The culmination of this analysis is a four‑tier taxonomy tree: Core Building Block → Main Layer → Sub‑Layer → Layout Options. This tree serves as a navigation tool that enables architects, researchers, and policymakers to quickly locate the set of components that satisfy a given set of functional and non‑functional requirements. By visualising the design space, the taxonomy helps in evaluating alternative architectures, estimating performance, and anticipating interoperability challenges.

Beyond the technical classification, the paper stresses the importance of standardisation. It surveys existing standardisation initiatives such as the Accord Project, ChinaLedger, R3, and especially ISO/TC 307, which has established working groups on reference architecture, taxonomy, and ontology. The authors argue that the proposed taxonomy can be adopted as a meta‑model for these bodies, providing a common language that facilitates the creation of interoperable specifications, certification schemes, and regulatory guidelines. They also outline potential benefits: accelerated industry adoption, clearer legal frameworks, improved security and privacy guarantees, and a foundation for future research on blockchain governance and economics.

In conclusion, the authors acknowledge that the taxonomy is not a static artifact; as blockchain technology evolves, new layers, sub‑components, and layouts will emerge. They call for continuous updates, empirical validation through real‑world deployments, and active feedback loops with standardisation organisations. The work thus positions the taxonomy as both a practical design aid and a stepping stone toward a globally recognised reference architecture for blockchain and distributed ledger technologies.