BIS, Swift and Central Banks Validate Post-Quantum Cryptography for Payments

The Bank for International Settlements (BIS), in collaboration with Swift and central banks from Italy, France, and Germany, has completed a major experiment assessing how payment systems can transition to post-quantum cryptography (PQC) — a critical step in safeguarding the global financial system against future quantum computing threats.

The initiative, Project Leap Phase 2, was led by the BIS Innovation Hub Eurosystem Centre alongside the Bank of Italy, the Bank of France, Deutsche Bundesbank, Nexi-Colt, and Swift. The project tested the use of post-quantum cryptographic algorithms in a live-like operational environment, specifically within the Eurosystem’s TARGET2 real-time gross settlement system.

As part of the experiment, traditional digital signatures were replaced with quantum-resistant alternatives during the execution of liquidity transfers. This required modifications across multiple system components to ensure compatibility with updated cryptographic libraries — highlighting the scale and complexity of migrating mission-critical financial infrastructure.

All test scenarios were completed successfully, demonstrating that payment systems can operate with post-quantum cryptography. However, the results also revealed significant performance differences between classical and post-quantum algorithms, underlining the need for further testing, optimisation, and phased implementation before large-scale deployment.

Beyond technical performance, the BIS emphasised that achieving quantum resilience is as much an organisational challenge as it is a technological one. Key issues include institutional awareness, governance, skills development, resource allocation, cryptographic agility, and system inventory management.

“Migrating payment systems to quantum-safe solutions is a complex and high-stakes process that affects the entire financial ecosystem,” the BIS noted. “Project Leap Phase 2 highlighted the importance of timely preparation and close collaboration across institutions to ensure long-term financial stability in the face of emerging quantum threats.”

The findings reinforce the urgency for financial institutions to begin structured post-quantum transition strategies today, rather than waiting for quantum computers to reach cryptographically relevant scale.

Reference: Finextra