In a recent research note, Grayscale, a digital asset management firm, expressed support for accelerating efforts to make public blockchains resilient to quantum computing threats. The note emphasizes that while technical solutions to this issue already exist, the more significant challenge is achieving consensus among decentralized communities to implement these solutions.
This comes after Google Quantum AI released a paper suggesting that breaking Bitcoin's elliptic curve cryptography could be achieved with fewer than 500,000 physical qubits, potentially in under nine minutes, and giving an attacker around a 41% chance of stealing funds before a transaction is confirmed. The paper's findings have significant implications, with varying levels of quantum risk across different blockchains depending on their transaction models, consensus mechanisms, and block times.
From a purely technical standpoint, Bitcoin is argued to have a lower quantum risk due to its UTXO model, proof-of-work consensus, lack of native smart contracts, and specific address types. However, the major question revolves around addressing the approximately 6.9 million BTC in wallets with permanently exposed public keys on the blockchain, including those believed to belong to Satoshi Nakamoto. Possible solutions include burning these coins, taking no action, or limiting their release rate, but the decision is complicated by the history of contentious debates within the Bitcoin community over protocol changes. In contrast, Ethereum faces different challenges, with multiple identified attack vectors worth over $100 billion and a significant need for quantum migration planning.