Time Is Running Out for Bitcoin to Mitigate Quantum Computing Threat

Not all aspects of bitcoin are vulnerable to quantum computer attacks. The process of mining, which involves adding new blocks to the blockchain, relies on a type of mathematics called hashing that quantum computers are unable to break. As a result, the ledger and the rule that new bitcoins can only be created through mining would remain intact in the event of a quantum attack. However, ownership of bitcoins would be at risk. Bitcoin wallets are secured by a different type of mathematics that converts a private key into a public address. This math works in one direction but not the other, preventing unauthorized access to coins. A quantum algorithm known as Shor's algorithm can bypass this security measure, and a recent paper by Google demonstrated that this attack could be carried out with fewer resources than previously thought. This article explores the potential risks and responses to the quantum threat. Approximately 6.9 million bitcoins, or one-third of all mined coins, are stored in wallets with publicly visible keys, making them vulnerable to quantum attacks. This includes early bitcoins and any wallet that has been used for a transaction, as spending reveals the key. A quantum attacker would not need to rush, as they could target wallets with exposed keys at their leisure. Even Satoshi Nakamoto's untouched 1 million bitcoins are at risk. The 2021 Taproot upgrade inadvertently increased the problem by publishing keys for any spent bitcoins. While there are ongoing debates and proposals for addressing the quantum threat, such as adding quantum-safe address types or installing a detection system, none have gained broad support from bitcoin's core developers. Ethereum, on the other hand, has had a formal quantum-resistant program in place since 2018 and is actively working on migrating to new, quantum-resistant mathematics. The main challenge for bitcoin is its lack of a central authority and governance process, which makes coordinating a response to the quantum threat more difficult. The network's development culture prioritizes stability and rare, hard changes, which may hinder its ability to address the quantum threat in time.