Research Summary - Scaling Blockchains: A Comprehensive Survey


  • A. Hafid, A. S. Hafid, and M. Samih, “Scaling Blockchains: A Comprehensive Survey,” in IEEE Access, vol. 8, pp. 125244-125262, 2020, DOI: 10.1109/ACCESS.2020.3007251.


Core Research Question

  • What are the existing solutions to blockchain scalability? What are the advantages and disadvantages of those existing scalability solutions?


  • This paper studied the existing blockchain scalability solutions. The authors classified these solutions into two categories: First layer solutions (e.g., sharding, bigger blocks, and DAG) and second layer solutions (e.g., payment channels and side chains). In particular, the authors focused on solutions that use the concept of sharding, given that it is one of the most promising solutions to the scalability problem.

  • The paper presented a taxonomy in which the authors classify sharding based blockchain protocols based on committee formation and intra-committee consensus. Also, the paper analyzed the security of these protocols by computing the failure probability for one committee and for each epoch (i.e., one sharding round).


  • Survey and comparison


Discussion & Key Takeaways

  • The paper gives an overview of blockchain scalability and provides a general taxonomy to classify existing blockchain scalability solutions.

  • The authors provide a detailed comparison of existing solutions of scalability based on their performances (i.e., throughput, latency), advantages, and disadvantages.

  • Security analysis of sharding-based blockchain protocols was also discussed in this paper and an investigation of the trade-off between security and performance (throughput) based on the failure probability and years to fail is given.


  • Up to now, no thorough literature review contribution covering the same concerns as this paper. This later provides researchers with a holistic overview and comparison of the existing sharding-based blockchain solutions.