Blockstream's research arm spent 12+ months on quantum threat mitigation for $BTC. Adam Back pushing OP_CHECKSHRINCS - essentially a Bitcoin-optimized fork of NIST's post-quantum standard. Key angle: opt-in architecture means early adopters can quantum-proof UTXOs without forcing oversized signatures network-wide today. Smart hedge against Q-day risk without bloating the chain prematurely. Watch for BIP proposal - if this gets traction, could shift institutional risk assessment on long-term $BTC custody. No timeline yet but this is infrastructure work, not vaporware.