While researching real-world applications of post-quantum cryptography, I came across something pretty interesting. In February 2024, Lockheed Martin filed a U.S. patent (publication number US 2024/0048369 A1) describing a quantum-resistant secure communications system. That alone isn’t surprising given Lockheed’s defense background. But as I read through the patent, something stood out - they explicitly reference and reuse code from the Quantum Resistant Ledger (QRL).

The document directly cites QRL’s GitHub repo and uses its implementation of XMSS (hash-based signature scheme standardized by NIST in SP 800-208). Essentially, the patent builds upon QRL’s architecture to propose a secure communication network - likely intended for use in sensitive military or corporate environments.

Even more interesting is that QRL is currently transitioning to SPHINCS+, which was officially selected by NIST in their first round of post-quantum digital signature standards. Unlike XMSS, SPHINCS+ is stateless, making it a better fit for high-throughput environments and broader adoption. This transition could significantly improve the flexibility and scalability of QRL, especially for applications like the one Lockheed describes.

What caught my attention is how a major defense contractor is borrowing directly from open-source crypto code, particularly from a project like QRL, which many still see as niche within the broader blockchain space.


If anyone here knows more about the connection between QRL and real-world defense applications, or has updates on how the SPHINCS+ migration is progressing within QRL, I’d love to hear your thoughts. This might be an early sign that post-quantum blockchain infrastructure is getting picked up in places we didn’t expect.