A Taxonomy of Proof-of-Stake Consensus Mechanisms: Classification, Security, and Economic Implications

Level: BA/MA
Responsible person: Dr. Sheng Nan Li
Keywords:  Proof-of-stake, Consensus, Crypto economic, Literature review

Proof-of-Stake (PoS) consensus mechanisms have emerged as a leading alternative to Proof-of-Work (PoW) due to their energy efficiency, scalability, and economic security. However, the growing diversity of PoS models—ranging from pure staking to delegated and hybrid approaches—creates a need for a structured classification framework. 

This thesis aims to develop a taxonomy of PoS mechanisms by systematically analyzing their design variations, security trade-offs, and economic implications. The study will categorize PoS models based on consensus, block (or transaction) finalisation, monetary policy, stake weighting, validator selection, slashing conditions, governance structures, and decentralisation levels. Additionally, it will evaluate the resilience of different PoS models against common attacks, such as long-range attacks, stake centralised, and cartel formation. 

Through formal classification, case studies, and comparative analysis, this research will contribute to a deeper understanding of PoS consensus models and guide protocol designers in optimising security, fairness, and decentralisation. 

References: 

[1] Tasca, P., & Tessone, C. J. (2019). A Taxonomy of Blockchain Technologies: Principles of Identification and Classification. Ledger, 4. 
[2] Spychiger, F., Tasca, P., & Tessone, C. J. (2021). Unveiling the importance and evolution of design components through the “tree of blockchain”. Frontiers in Blockchain, 3, 613476. 
[3] Kiayias, A., Russell, A., David, B., & Oliynykov, R. (2017, July). Ouroboros: A provably secure proof-of-stake blockchain protocol. In Annual international cryptology conference (pp. 357-388). Cham: Springer International Publishing. 

[4] Saleh, F. (2021). Blockchain without waste: Proof-of-stake. The Review of financial studies, 34(3), 1156-1190.