Quantum-Resilient Privacy Ledger (QRPL): A Sovereign Digital Currency for the Post-Quantum Era

TL;DR

This paper introduces QRPL, a quantum-resistant digital currency architecture that enhances privacy, security, and decentralization using post-quantum cryptography and zero-knowledge proofs, addressing CBDC limitations.

Contribution

It presents a novel quantum-resilient digital currency design incorporating NIST-standardized PQC, privacy-preserving proofs, and a privacy-weighted PoS consensus, advancing CBDC privacy and security.

Findings

Design of ephemeral proof chains for unlinkable transactions

A privacy-weighted PoS consensus mechanism

A zero-knowledge proof-based privacy-preserving disclosure method

Abstract

The emergence of quantum computing presents profound challenges to existing cryptographic infrastructures, whilst the development of central bank digital currencies (CBDCs) has raised concerns regarding privacy preservation and excessive centralisation in digital payment systems. This paper proposes the Quantum-Resilient Privacy Ledger (QRPL) as an innovative token-based digital currency architecture that incorporates National Institute of Standards and Technology (NIST)-standardised post-quantum cryptography (PQC) with hash-based zero-knowledge proofs to ensure user sovereignty, scalability, and transaction confidentiality. Key contributions include adaptations of ephemeral proof chains for unlinkable transactions, a privacy-weighted Proof-of-Stake (PoS) consensus to promote equitable participation, and a novel zero-knowledge proof-based mechanism for privacy-preserving selective disclosure. QRPL aims to address critical shortcomings in prevailing CBDC designs, including risks of pervasive surveillance, with a 10-20 second block time to balance security and throughput in future monetary systems. While conceptual, empirical prototypes are planned. Future work includes prototype development to validate these models empirically.