A Practical Post-Quantum Distributed Ledger Protocol for Financial Institutions

TL;DR

This paper introduces a post-quantum, privacy-preserving distributed ledger protocol tailored for financial institutions, utilizing lattice-based cryptography and zero-knowledge proofs to enhance confidentiality and auditability.

Contribution

It presents a novel lattice-based transaction scheme with zero-knowledge proofs and a new commitment equivalence method, improving privacy and efficiency for financial ledgers.

Findings

Developed a post-quantum secure transaction scheme

Designed a compact range-proof for multi-asset transactions

Provided security analysis demonstrating protocol robustness

Abstract

Traditional financial institutions face inefficiencies that can be addressed by distributed ledger technology. However, a primary barrier to adoption is the privacy concerns surrounding publicly available transaction data. Existing private protocols for distributed ledger that focus on the Ring-CT model are not suitable for adoption for financial institutions. We propose a post-quantum, lattice-based transaction scheme for encrypted ledgers which better aligns with institutions' requirements for confidentiality and audit-ability. The construction leverages various zero-knowledge proof techniques, and introduces a new method for equating two commitment messages, without the capability to open one of the commitment during the re-commitment. Subsequently, we build a publicly verifiable transaction scheme that is efficient for single or multi-assets, by introducing a new compact range-proof. We then provide a security analysis of it. The techniques used and the proofs constructed could be of independent interest.