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

A radical approach to addressing the potential threat of quantum computing to the Bitcoin network has been put forward by developers, who suggest that instead of imposing a pre-emptive freeze on vulnerable coins, the network should wait for an attacker to demonstrate their capabilities before taking action. This 'wait and react' strategy relies on a 'canary' system, which involves 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 will trigger a network-wide freeze of older wallets. The proposal also includes a financial incentive, where users can contribute to a bounty that will be paid to the first entity to demonstrate a quantum attack. However, this approach assumes that the attacker will be motivated by the bounty rather than seeking to maximize their profits through theft. Bitcoin wallets are currently vulnerable to quantum computing attacks due to their reliance on digital signature schemes that can be broken by advanced computers. A recent research paper by Google has lowered estimates for the resources required to launch such an attack, leading some to predict that the risk window may be sooner than previously thought. The new 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 of BIP-361 have argued that it is overly authoritarian and could result in the confiscation of coins that are not migrated in time. The 'wait and react' strategy is designed to avoid this outcome, while also introducing a 'safety window' that makes it harder for attackers to launch stealth attacks. However, the approach is not without its risks, and relies on an assumption that the first entity capable of breaking Bitcoin's security will choose to claim the bounty rather than launch a large-scale attack. If this assumption proves to be incorrect, the network may be left vulnerable to a catastrophic attack, and the consequences could be severe.