Time is Running Out for Bitcoin to Counter Quantum Computing Threat

Not all aspects of bitcoin are vulnerable to quantum computing. The process of bitcoin mining, which utilizes a type of mathematics known as hashing, is resistant to quantum attacks. This means that the creation of new blocks and the overall operation of the blockchain would remain intact. However, the ownership of bitcoins is at risk. Quantum computers can potentially break the one-way math problem that secures bitcoin wallets, allowing them to spend coins without the owner's permission. Approximately 6.9 million bitcoins, roughly one-third of all mined coins, are at risk due to exposed public keys. This includes early bitcoins and any wallet that has been spent from, as spending reveals the public key. A quantum attacker could work through these wallets at their own pace, without needing to race against transactions in progress. Even Satoshi Nakamoto's 1 million untouched bitcoins are at risk. The 2021 Taproot upgrade has expanded the problem by publishing the key protecting remaining coins at an address after a transaction. While there are proposals to address the issue, such as adding quantum-safe address types or 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 since 2018 and is actively working on a migration plan. The lack of a centralized authority and a governance process in bitcoin makes it harder to implement effective solutions. The network's development culture prioritizes stability and treats any central authority as a failure mode, making it structurally harder to solve the quantum problem. Migrating the exposed coins requires decisions that the network has avoided for twenty years, such as freezing old address formats or allowing exposed coins to move to new quantum-safe addresses. The window to respond to the quantum threat may already be closing, and developers face the question of whether a network built to resist coordinated change can coordinate the biggest security upgrade in its history before the hardware catches up.