Bitcoin Developers Propose '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 to the network's security. Instead of imposing a blanket freeze on vulnerable coins, the proposed 'wait and react' strategy would only trigger a network-wide restriction if a quantum-capable attacker demonstrates their capabilities on-chain. This approach is based 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, serving as public proof of the threat and automatically triggering a network-wide freeze. The proposal includes a bounty system, where users can contribute bitcoin to reward the first entity to demonstrate a quantum attack, rather than attempting to exploit vulnerable wallets. However, this approach relies on the assumption that the first entity capable of breaking Bitcoin's security would claim the bounty rather than executing a large-scale theft. This assumption has sparked debate, as it goes against the network's historical approach to preventing worst-case scenarios. The proposed system also includes a 'safety window' to make stealth attacks more difficult, allowing vulnerable coins to move but preventing the recipient from spending them for an extended period. If the canary is triggered during this window, those coins would be frozen retroactively, increasing the risk to any attacker attempting to quietly extract funds. The proposal is seen as an alternative to BIP-361, which would impose a fixed five-year timeline for phasing out vulnerable addresses and invalidating old signature schemes. Critics have argued that this approach is 'authoritarian and confiscatory,' undermining Bitcoin's core principle of private key holder control. The 'wait and react' strategy aims to reduce the risk of disrupting users prematurely, but its success depends on the assumption that the first quantum-capable attacker will prioritize the bounty over exploiting the network's vulnerabilities.