Bitcoin Developers Propose 'Wait and React' Strategy to Counter Quantum Computing Threats

The Bitcoin community is considering a novel approach to mitigate the risks posed by quantum computing: instead of preemptively freezing vulnerable coins, the network would wait for a quantum-capable attacker to demonstrate their capabilities and then react. This 'wait and react' strategy relies on a 'canary' system, where a small amount of bitcoin is placed in a special address that can only be unlocked by a quantum-capable attacker. If the attacker unlocks the address, it would serve as public proof that the quantum threat is real, triggering a network-wide freeze of older wallets. The proposal is designed to provide an alternative to a previously suggested five-year timeline for implementing restrictions on older bitcoin wallets. This timeline, outlined in BIP-361, has been criticized for being 'authoritarian and confiscatory' as it would render any unmigrated coins permanently frozen. The new proposal includes a financial incentive, where users can contribute to a bounty that rewards the first entity to demonstrate a quantum attack publicly. However, this approach assumes that the first entity capable of breaking Bitcoin's security would claim the bounty rather than carrying out a large-scale theft. This assumption has raised concerns, as it goes against the network's historical emphasis on preventing worst-case scenarios. If the assumption proves incorrect, Bitcoin may face the worst of both worlds: the catastrophic consequences of a quantum attack and the realization that a fixed-timeline defense could have prevented it. The proposal also introduces a 'safety window' to make stealth attacks more difficult, during which vulnerable coins could still be moved but the recipient would be unable to spend them for an extended period.