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

A recent proposal is sparking debate among Bitcoin developers, who are considering a novel approach to address the potential threat of quantum computing to the network. Instead of imposing a blanket freeze on vulnerable coins, the plan involves waiting for an attacker to demonstrate their capabilities and then triggering a network-wide response. The 'canary' system, proposed by BitMEX Research, would put a small amount of bitcoin in a special address that can only be accessed by a quantum-capable attacker. If the attacker spends the bitcoin, it would serve as proof that the threat is real, automatically triggering a network-wide freeze of older wallets. This approach is designed to provide an alternative to a fixed five-year timeline for phasing out vulnerable addresses, which has been met with criticism for being 'authoritarian and confiscatory.' The new proposal includes a financial incentive, where users can contribute to a bounty that rewards the first entity to demonstrate a quantum attack. However, this plan relies on the assumption that the attacker will claim the bounty rather than exploiting the vulnerability for personal gain, which some argue is an uncomfortable bet. The 'canary' system also introduces 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, the coins would be frozen retroactively, increasing the risk for potential attackers. While this approach reduces the risk of disrupting users prematurely, it raises concerns about the potential consequences if the bet fails, leaving Bitcoin vulnerable to a catastrophic attack.