Bitcoin or achieving anti-quantum security, while the privacy issue of Bitcoin Lightning Network remains unresolved

Bitcoin Even after the completion of the anti-quantum upgrades for on-chain and Bitcoin Lightning Network , the payment system in off-chain still needs to be modified. A study published on September 12 stated that there are five parts of Bitcoin Lightning Network which need to be independently upgraded against quantums.

PQLN: a hybrid anti-quantum scheme with off-chain components

The paper proposes a hybrid post-quantum expansion called PQLN and is implemented in the manner of a rust-lightning research prototype. Components targeted by this program include: gossip protocols for distributing nodes with channel information, encrypted inter-node connections, signed invoices with reusable payment requests, and onion data packets that hide routing details.

Currently Bitcoin Lightning Network relies on ECDSA, Schnorr signature or ECDH based on secp256k1 for these functions. PQLN retains the original classical mechanism while adding ML-DSA signatures in gossip, invoice and payment requests and introducing hybrid ML-KEM key exchange at the transport layer, Pay Onion Postings and BOLT 12 privacy pathways.

Compatibility testing and limitations

The authors constructed a forked version of Rust-Lightning with feature switches, as well as a modified LDK sample node. In the 12-scenario test matrix, an anti-quantum version compiled based on the same RUST-LIGHTNING code can coexist with the original nodes. Under mixed environments, visual routing differs from configuration either by using classical protection or direct security failures.

However, this compatibility does not mean that the entire network is ready for migration. The relevant code repository explicitly identifies it as a research product and no cross-testing of other Bitcoin Lightning Network implementations has been carried out.

bandwidth Expenditure higher than calculated

The test results showed that the communication overhead was much greater than cryptography computation itself. During a network-wide mapping static synchronization phase, the default combination of ML-DSA-44 with ML-KEM-768 increased gossip downloads to 10.2 times the original version and stored data in graphs by 8.8 times. A smaller FN- DSA (originating from Falcon) configuration could reduce download duplicates to 4.2 times, but NIST still listed Falcon as an option currently under development rather than the final standard.

The privacy payment route also costs bandwidth . A fixed 21.8 kilobyte anti-quantum cryptographic list increases per hop from 19 to 53 milliseconds on a 10 Mbit/s analog link, and reaches 160 to 187 milisecond per jump under 1 Mbit / s. In comparison, the ML-DSA-44 signature takes an average of only 327 microseconds at author's 16-core AMD Ryzen Threadripper PRO 3955WX 64GB memory workstation but this single machine basic performance test does not equal end-to-end payment latency.

on-chain Risks to be addressed

PQLN is not covered by the Bitcoin layer of risk. It does not protect funds outputs, pledges outpots, and HTLC outpits as well as punishes trading pair 's corresponding on-chain keys, so it still requires anti-quantum transformations at the main chain level to secure channel funds.

The preprint was supposed to assume possible future quantum attackers, and did not report that either Bitcoin or Bitcoin Lightning Network is currently undergoing a quantum breakthrough. Prototype experiments showed that the off-chain defense of Bitcoin Lightning Network , could be upgraded independently from previous tests on Bitcoin , but does not equal network readiness for migration.