Randomness in Blockchain: A Comprehensive Survey of Pseudo-Random Number Generation (PRNG) and Quantum Random Number Generation (QRNG)

Blockchain technology has grown rapidly and gained extensive adoption across various sectors due to its transparency and security benefits. Randomness plays crucial role in blockchain systems by ensuring fairness, security, and unpredictability in decentralized systems. This survey comprehensively analyzes randomness generation methods, particularly Pseudo-Random Number Generators (PRNGs) and Quantum Random Number Generators (QRNGs), in blockchain systems. PRNGs, while efficient, are vulnerable to predictability issues, whereas QRNGs offer higher security but require specialized hardware and have higher costs. The paper examines state-of-the-art randomness generation techniques, highlighting their strengths, limitations, and implications for blockchain security and efficiency. A novel taxonomy is proposed, categorizing randomness approaches into on-chain and off-chain mechanisms using PRNGs and QRNGs. By providing an in-depth exploration of existing methods and advancements, this survey enables readers to evaluate trade-offs and identify the most suitable approaches for specific blockchain applications. The survey also addresses gaps in current research and proposes future directions for secure and efficient randomness generation in decentralized systems. To the best of our knowledge, this paper is the first survey that analyses randomness techniques in blockchain using PRNG and QRNG.