SHRINCS BIP published: Quantum-secure Bitcoin comes with a catch

A newly published BIP called SHRINCS proposes an opt‑in, quantum‑resistant signature scheme for Bitcoin that would protect outputs created under the new standard but does not automatically secure existing addresses. The approach relies on post‑quantum cryptography that produces substantially larger signatures and therefore increases on‑chain footprint and fees. Deployment would require consensus adoption and active migration of funds to the new output type, leaving legacy UTXOs exposed until moved. The net implication: Bitcoin can be made quantum‑secure in practice, but only at the cost of higher transaction costs, coordination overhead, and phased migration risk.