Kamal Swami

Post-Quantum Cryptography: A Shield Against Quantum Threats

Quantum computing is one of the emerging technologies that would be able to solve complex computing problems in a few seconds. But the use of this technology can be risky for today’s cryptographic systems. Algorithms such as RSA, ECDSA, and ECDH, which are considered the backbone of current computing security, will no longer be able to perform their tasks. This will put the security of sensitive data and secure communications at the edge of exposure.

To combat this challenge, organisations are now exploring the possibilities of deploying Post-Quantum Cryptography (PQC) technology to protect their data. Although this will not happen overnight, considering the expected loss, developers can start preparing their systems today. In this blog, we’ll explore how developers can migrate a Node.js (or hybrid) system to PQC using open-source tools like Open Quantum Safe (liboqs), BouncyCastle, and custom bindings.

1. Integrate PQC Libraries

Your first step is to bring PQC-ready libraries into your systems:

• Open Quantum Safe (liboqs): Available via native bindings or WebAssembly.
• BouncyCastle PQC: A strong choice for Java-based services in hybrid architectures.
• Node.js Options:
• node-liboqs – unofficial bindings for liboqs.
• WebAssembly wrappers – a fallback when native bindings aren’t available.

2. Replace or Wrap Existing Crypto Systems

• Hybrid Key Exchange (ECDH + Kyber):

Instead of crypto.createECDH('prime256v1'), adopt the hybrid approach that has the features of classical ECDH with Kyber. This will protect your system from both classical and quantum attackers.

• Digital Signatures with Dilithium:

Replace traditional ECDSA signatures with Dilithium from liboqs. This will minimise the impacts of quantum computing without any significant change in your performance.

3. Key Management & Migration

Adopting PQC isn’t limited to swapping algorithms—it also means revisiting how you manage keys:

• Use secure storage solutions such as Supabase Vault or KMS.
• Write migration scripts to:
• Re-issue user key pairs in hybrid formats (ECDH + Kyber).
• Provide fallback to legacy ECDSA for compatibility.

4. Update TLS/SSL Stack

At present, Node.js doesn’t support PQC integrated in TLS. This can be done following the steps mentioned below:

• Using OpenSSL with liboqs support.
• Terminating TLS at a proxy (nginx, stunnel, haproxy) compiled with PQC.
• Managing traffic from the proxy to your Node.js backend.

This will keep your system compatible with the ongoing changes while preparing for quantum-safe connections.

5. Update JWT Signing & Tokens

If you’re using JWTs, replace RSA/ECDSA signatures with Dilithium-signed tokens. Extend existing libraries like jsonwebtoken with custom sign/verify handlers if needed.

6. API Changes

You will also need to adjust API endpoints:
• Login & Wallet APIs: Accept hybrid public keys.
• Token APIs: Return and verify PQC-based signatures.
7. Testing & Benchmarking

Thorough testing is of high importance when migrating to quantum computing:

• Unit test Kyber key exchange, Dilithium signing, and hybrid fallback logic.
• Note down the key metrics:
• Key generation time
• Handshake latency
• Signature size

Compare performance between classical and PQC implementations to measure overhead.

8. Ensure Backwards Compatibility

Not every client will support PQC immediately. Solve this with API versioning:

• v1: Legacy RSA/ECDSA/ECDH
• v2: Hybrid PQC (ECDH + Kyber, Dilithium)

Implement a negotiation layer to select the best crypto scheme depending on the client's capability.

9. Update Documentation

Don’t leave your teams guessing—update your documentation to include:

• New key formats and API endpoints.
• Migration strategies.
• Guidance for fallbacks and legacy compatibility.
10. Explore Optional Tools & Libraries

For smoother integration, consider using:

• @openquantumsafe/liboqs (C bindings)
• node-ffi-napi (Node.js bindings for C libraries)
• jsonwebtoken (extended for PQC signatures)
• WebAssembly loaders (for browser compatibility)
Conclusion

Although the concept of quantum computing is in its primary stage, there is a need to adopt crypto agility. By adopting hybrid PQC strategies, you can protect your applications against both classical and quantum threats.

Migration to quantum computing is not only changing algorithms, but it is also remapping the whole management, TLS termination, and backwards compatibility. With the help of tools like liboqs, it will be possible to shift to the new era of computing.