What is post-quantum cryptography?
Post-quantum cryptography is a group of classical algorithms designed to resist attacks by both conventional and future quantum computers. It replaces vulnerable public-key methods such as RSA and elliptic-curve cryptography. It does not require a quantum computer or quantum network. Banks can deploy the new algorithms in existing software, protocols and hardware after compatibility testing.
Post quantum cryptography in brief
| Term | post quantum cryptography |
|---|---|
| Meaning | Post-quantum cryptography is a group of classical algorithms designed to resist attacks by both conventional and future quantum computers. It replaces vulnerable public-key methods such as RSA and elliptic-curve cryptography. It does not require a quantum computer or quantum network. Banks can deploy the new algorithms in existing software, protocols and hardware after compatibility testing. |
| Bank use | Banks use public-key cryptography in TLS, certificates, payment connections, code signing, document signatures and key exchange. Migration begins with a cryptographic inventory showing algorithm, key size, library, owner and data lifetime for every use. Long-lived confidential data moves first because an attacker can record it now and decrypt it later when stronger quantum machines exist. |
| Main risk | Treating migration as one algorithm swap misses hard-coded lengths, old appliances, partner protocols and long-lived signatures. A PQC migration needs crypto-agility so teams can adopt quantum-safe cryptography and quantum-resistant encryption through configuration or shared services. Banks also test performance, certificate chains, hardware security modules and recovery. A new algorithm can fail too, so fallback and staged deployment matter. |
| Rule set | NIST published its first post-quantum standards in 2024. The BSI recommends hybrid deployment for high-assurance use, and the G7 Cyber Expert Group published a financial-sector transition roadmap. The BIS roadmap starts with awareness and cryptographic inventory. DORA makes the migration part of broader ICT risk and resilience planning. |
| Detailed page | Detailed guide |
How does post quantum cryptography work?
Post-quantum cryptography is a group of classical algorithms designed to resist attacks by both conventional and future quantum computers. It replaces vulnerable public-key methods such as RSA and elliptic-curve cryptography. It does not require a quantum computer or quantum network. Banks can deploy the new algorithms in existing software, protocols and hardware after compatibility testing.
A sufficiently capable quantum computer could use Shor's algorithm against current public-key cryptography. NIST standardized ML-KEM for key establishment and ML-DSA and SLH-DSA for signatures. Keys, ciphertexts and signatures are often larger than today's equivalents, which affects protocols and fixed fields. Hybrid deployment combines a classical and a post-quantum method during the transition.
Why does post quantum cryptography matter to banks?
Banks use public-key cryptography in TLS, certificates, payment connections, code signing, document signatures and key exchange. Migration begins with a cryptographic inventory showing algorithm, key size, library, owner and data lifetime for every use. Long-lived confidential data moves first because an attacker can record it now and decrypt it later when stronger quantum machines exist.
What risks and design choices come with post quantum cryptography?
Treating migration as one algorithm swap misses hard-coded lengths, old appliances, partner protocols and long-lived signatures. A PQC migration needs crypto-agility so teams can adopt quantum-safe cryptography and quantum-resistant encryption through configuration or shared services. Banks also test performance, certificate chains, hardware security modules and recovery. A new algorithm can fail too, so fallback and staged deployment matter.
Which rules and standards apply to post quantum cryptography?
NIST published its first post-quantum standards in 2024. The BSI recommends hybrid deployment for high-assurance use, and the G7 Cyber Expert Group published a financial-sector transition roadmap. The BIS roadmap starts with awareness and cryptographic inventory. DORA makes the migration part of broader ICT risk and resilience planning.
Post quantum cryptography in Germany, Austria and Switzerland
BaFin and the ECB supervise operational risk at German banks, the FMA in Austria and FINMA in Switzerland. The BSI supplies German technical guidance. Frankfurt's Bundesbank worked with the Banque de France and BIS Innovation Hub on Project Leap, which tested quantum-resistant protection for central-bank communications. The experiment links standards work with the payment infrastructure that banks already use.
About Finance Loop: post quantum cryptography
Finance Loop brings together bank technology, payments, capital markets and supervisory professionals who work on post quantum cryptography. In Frankfurt, technical decisions meet the systems of the ECB, Bundesbank, Deutsche Börse and the banks based there.
The detailed page on post quantum cryptography and Finance Loop events connect the definition with financial-sector projects and practitioners.