Sharding for Scalable Blockchain Networks

Faiza Hashim, Khaled Shuaib, Nazar Zaki

Research output: Contribution to journalReview articlepeer-review

26 Citations (Scopus)


Blockchain technology has been extended from bitcoin transactions to applications in multiple domains. Scalability has been identified as a major challenge in large-scale blockchain networks because of the number of possible participants. Scalability becomes a consideration because the blockchain distributed ledger is replicated at all participating nodes, and the block validation process may experience transaction throughput, storage, latency, and energy consumption hurdles. Sharding is a database technique adopted in blockchain technology to attempt to resolve the scalability issue. Sharding enables parallelization of transactions to improve transaction throughput in a blockchain network where a single ledger is shared in each shard to optimize the storage issue of blockchain scalability. Herein, we present a detailed review focusing on scalability challenges in blockchain and solutions provided by database sharding to resolve these challenges. Various sharding consensus protocols are examined along with our insights into existing solutions. Extensive open challenges are provided in this research for future researchers, including cross-shard communication overhead, shard formation, node assignment to shards, optimal number of shards in a network and shard takeover attacks.

Original languageEnglish
Article number2
JournalSN Computer Science
Issue number1
Publication statusPublished - Jan 2023


  • Blockchain
  • Consensus protocols
  • Database sharding
  • Distributed ledger
  • Scalability

ASJC Scopus subject areas

  • Artificial Intelligence
  • General Computer Science
  • Computer Networks and Communications
  • Computer Science Applications
  • Computational Theory and Mathematics
  • Computer Graphics and Computer-Aided Design


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