Bitcoin Developers Propose 'Wait and React' Strategy to Counter Quantum Threat

The Bitcoin community is considering a novel approach to addressing the potential threat of quantum computing: instead of imposing a pre-emptive freeze on vulnerable coins, the network would wait for an attacker to demonstrate their capabilities and then react. This 'wait and react' strategy, proposed by BitMEX Research, involves placing a small amount of bitcoin in a special address that can only be unlocked by a quantum-capable attacker. If the attacker accesses the funds, it would trigger a network-wide freeze of older wallets. The proposal includes a bounty system, where users can contribute bitcoin to incentivize the first entity to demonstrate a quantum attack, rather than exploiting vulnerable wallets for personal gain. However, this approach relies on the assumption that the attacker will claim the bounty rather than attempting a large-scale theft. The 'canary' system is designed to reduce the risk of premature disruption to users, but it also introduces a 'safety window' to make stealth attacks more difficult. If the canary is triggered during this window, vulnerable coins could be frozen retroactively, increasing the risk for any attacker attempting to quietly extract funds. Critics argue that this approach is based on an uncertain bet, as it is unclear whether an attacker would prioritize claiming the bounty over executing a potentially massive theft. The proposal is seen as an alternative to BIP-361, which would impose a fixed five-year timeline for phasing out vulnerable addresses and freezing unmigrated coins. The Bitcoin community has historically resisted protocol-level interventions, such as the hard fork that reversed the 2016 DAO hack on Ethereum, and the 'wait and react' strategy may be seen as a more conservative approach to addressing the quantum threat.