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

The Bitcoin community is considering a novel approach to address the potential threat of quantum computing: instead of imposing a pre-emptive freeze on vulnerable coins, the network would only take action if a quantum-capable attacker demonstrates their capabilities. 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 address is accessed, it would trigger a network-wide freeze of older wallets. The proposal also includes a bounty system, where users can contribute bitcoin to incentivize the first entity to demonstrate a quantum attack, rather than exploiting the vulnerability for personal gain. However, this approach assumes that the attacker will prioritize claiming the bounty over executing a large-scale theft. This assumption has sparked debate, as it contradicts the network's historical emphasis on worst-case scenario planning and decentralized control. The proposal is an alternative to BIP-361, which would impose a fixed five-year timeline for phasing out vulnerable addresses and invalidating old signature schemes. Critics argue that this approach is overly restrictive and undermines the core principles of Bitcoin. The 'canary' system aims to reduce the risk of premature disruption, but it rests on the bet that the first entity capable of breaking Bitcoin's security would choose to claim the bounty rather than steal millions of bitcoin. If this bet fails, the network risks facing the worst of both worlds: the catastrophic consequences of a quantum attack and the realization that a fixed-timeline defense would have prevented it.