Post Quantum Lightning: Layer by Layer

A Delving Bitcoin write-up walking through how a quantum computer would affect the Lightning Network, layer by layer. It identifies which parts of the BOLT specifications depend on elliptic-curve cryptography and would therefore need post-quantum replacements: the channel signatures (BOLTs 2/3/5), the Sphinx onion-routing packet that relies on EC point blinding (BOLT 4), gossip signatures (BOLT 7), the encrypted transport (BOLT 8), and signed invoices (BOLTs 11/12).

The author's reassuring conclusion is that while every layer needs some change, the protocol's overall structure and flows would survive largely intact. The post includes a comparison table of public-key and signature sizes across secp256k1 and the NIST post-quantum schemes, underscoring the recurring cost theme: post-quantum primitives are much larger, which matters acutely for an off-chain protocol built around compact packets.