Ironically, payment lightning ⚡️ channels may be the perfect environment for stateful post-quantum signatures. One of the biggest criticisms of stateful hash-based signatures like XMSS is that you must never sign 2 different messages with the same leaf. Channels already have a strictly increasing state counter, so you can simply map: State i → XMSS leaf i Surprisingly, this isn’t just a cryptographic property, but an economic one. In a well-designed lightning ⚡️ channel, signing 2 different states with the same counter is already irrational, even with ECDSA, because the counterparty can challenge the stale state and invalidate or penalize your attempt. The protocol already discourages equivocation. XMSS just aligns its security model with the protocol’s incentives. What was a wow realization from my today’s hacks? Sometimes the best use case for a stateful primitive is a stateful protocol. Checking edge cases…