A Review of Privacy-Preserving Cryptographic Techniques Used in Blockchain Platforms

Abstract

Due to its reliance on cryptographic techniques to ensure a high level of security, Blockchain technologies are witnessing widespread adoption in many domains ranging from decentralized Finance (DeFi), contract management, e-health, and cyber defense, to IoT among many others. However, quantum computing makes some cryptographic techniques used in the known blockchain platforms vulnerable and breakable. In this direction, this paper compares, classifies, and analyzes the cryptographic techniques used by well-known blockchain platforms, which are: Zerocash, Hyperledger Fabric, Monero, Ethereum, Bitcoin, and Hyperledger Indy. The forecited analysis is against three criteria: crypto-technique category, quantum resistance, and anonymity type. Finally, the discussion highlights the pros and cons of the studied techniques as well as presents some recommendations to improve privacy-preserving, quantum-safety, and security properties for each one.