Researchers from East Texas A&M University’s RELLIS Campus published PQLN, or Post-Quantum Lightning Network, on September 12, 2026. The project is described as the first working implementation to add quantum-resistant cryptography to Bitcoin’s main layer-2 scaling network. Released on GitHub as a nearly 11,000-line addition to a fork of rust-lightning, PQLN combines Bitcoin’s existing secp256k1-based cryptography with lattice-based ML-DSA signatures and ML-KEM key exchange, algorithms drawn from the family being standardized by the U.S. National Institute of Standards and Technology. The implementation covers Lightning gossip, peer transport, invoices, payment onions and BOLT-based offers, while allowing upgraded and legacy nodes to communicate. Tests recorded cryptographic overhead of 0.33 milliseconds or less per operation, although default ML-DSA settings increased gossip-download bandwidth by roughly 10 times; an alternative Falcon signature scheme reduced that increase to about four times. All 12 mixed-node interoperability scenarios produced zero stuck payments. PQLN protects Lightning’s communication and routing layers, not channel funds or on-chain Bitcoin elements, which would require a consensus upgrade. Discussions appeared on Delving Bitcoin and BitcoinTalk within days of the arXiv publication, and the open-source release includes a modified sample node for further study and potential adoption.