Blockchain in the Quantum Era: Surveying Security Challenges and Post-Quantum Cryptography

Recent advances in quantum technology are impacting cryptographic primitives, affecting their security. In this paper, we will survey the impact of these technologies on blockchain and distributed ledgers, and analyze the post-quantum primitives available to restore their security guarantees, including the latest NIST PQC standards ML-DSA-44 and SLH-DSA-SHA2-128s. Our analysis reveals critical trade-offs in signature size, key storage, and consensus resilience, highlighting challenges for IoT and PoW blockchains. Results underscore the urgency of improvements to the standardized NIST PQC algorithms to mitigate quantum risks to the blockchain without compromising throughput and decentralization.