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

The Bitcoin community is considering a novel approach to addressing the potential threat of quantum computing to the network's security. Instead of implementing a pre-emptive freeze on vulnerable coins, the proposal involves a 'wait and react' strategy that relies on the first quantum-capable attacker to reveal their capabilities in exchange for a bounty. This approach is outlined in a recent proposal by BitMEX Research, which introduces a 'canary' system designed to detect and respond to quantum attacks. The system works by placing a small amount of bitcoin in a special address that can only be unlocked by a quantum-capable attacker. If the address is accessed, it serves as public proof that the quantum threat has arrived, triggering a network-wide freeze on older wallets. This approach is seen as an alternative to a previous proposal, BIP-361, which would impose a fixed five-year timeline for phasing out vulnerable addresses and invalidating old signature schemes. Critics of BIP-361 have argued that it undermines Bitcoin's core principle of private key holder control, and could lead to the permanent freezing of unmigrated coins. The new proposal attempts to address these concerns by introducing a financial incentive for the first entity to demonstrate a quantum attack. Users can contribute bitcoin to the address, creating a bounty that rewards the attacker for revealing their capabilities rather than exploiting vulnerable wallets. The proposal also includes a 'safety window' designed to make stealth attacks more difficult, by allowing vulnerable coins to move but restricting their spending for an extended period. However, the success of this approach relies on the assumption that the first entity capable of breaking Bitcoin's security will choose to claim the bounty rather than execute a large-scale theft. This assumption has raised concerns, as it goes against the network's historical emphasis on preventing worst-case scenarios and minimizing the risk of catastrophic events.