In a recent research note, Grayscale, a digital asset management firm, expressed support for expedited efforts to enhance the quantum resistance of public blockchains. The note emphasizes that although the technical solutions to achieve this are already available, the more significant obstacle is convincing decentralized communities to implement these changes.
This development follows a week of intense industry response to a paper by Google Quantum AI, which suggested that breaking Bitcoin's elliptic curve cryptography could be achieved with fewer than 500,000 physical qubits, a substantial reduction from previous estimates, and could be executed in approximately nine minutes. An analysis by CoinDesk revealed that such an attack would give an attacker around a 41% chance of stealing funds before a Bitcoin transaction is confirmed. Grayscale's research highlighted four key takeaways from Google's study, including the potential for progress toward a cryptographically relevant quantum computer to occur in discrete jumps, making timelines difficult to predict.
Additionally, post-quantum cryptography is already mature and in use to secure internet traffic and certain blockchain transactions. The quantum risk also varies significantly across different blockchains, depending on their transaction models, consensus mechanisms, and block times. From a purely engineering perspective, it was argued that Bitcoin has a lower quantum risk compared to other chains due to its UTXO model, proof-of-work consensus, lack of native smart contracts, and the use of certain address types that are not quantum-vulnerable if not reused after spending.
However, the more challenging question revolves around the handling of approximately 6.9 million BTC in wallets with permanently exposed public keys on the blockchain, including an estimated 1 million believed to belong to Bitcoin's pseudonymous creator, Satoshi Nakamoto. Binance co-founder Changpeng Zhao recently raised a similar question, suggesting that if Satoshi's coins are moved during a potential migration, it could indicate that Satoshi is still active, and if they remain unmoved, it might be preferable to lock or effectively burn those addresses. Grayscale presents similar options - burning the coins, taking no action, or deliberately slowing their release by limiting the spending rate from vulnerable addresses. However, the firm notes that the Bitcoin community has a history of contentious debates over protocol changes, citing last year's dispute over image data stored in blocks as an example.
In contrast, Ethereum faces different challenges. Google's paper identified five attack vectors against Ethereum, worth over $100 billion in combined exposure, including account keys, admin keys on stablecoins, smart contract code, consensus mechanisms, and data availability.
Ethereum Foundation researcher Justin Drake estimated a 10% chance of quantum key recovery by 2032, and while the foundation has been staking aggressively, it has not publicly addressed quantum migration timelines.