Grayscale, a digital asset management firm, has released a research note advocating for expedited efforts to enhance public blockchains' resistance to quantum computing. The note asserts that while technical solutions are readily available, the more daunting task lies in garnering consensus among decentralized communities to implement these solutions. This comes on the heels of a week-long industry response to a paper by Google Quantum AI, which revealed that breaching bitcoin's elliptic curve cryptography could be achieved with fewer than 500,000 physical qubits, a substantial reduction from prior estimates, and could be executed in approximately nine minutes once the machine is primed. CoinDesk's analysis of the paper indicated that such an attack would afford an attacker a roughly 41% chance of stealing funds before a bitcoin transaction is confirmed.
The research note highlighted four key takeaways from the Google research that Grayscale found persuasive, including the potential for progress toward a cryptographically relevant quantum computer to occur in discrete jumps, rendering timelines unpredictable. Additionally, the note emphasized that post-quantum cryptography is a mature field, already securing internet traffic and certain blockchain transactions, and that quantum risk varies significantly across blockchains depending on their transaction models, consensus mechanisms, and block times.
From a purely technical standpoint, Grayscale argued that bitcoin has a lower quantum risk profile compared to other chains due to its UTXO model, proof-of-work consensus, lack of native smart contracts, and certain address types that are not vulnerable to quantum attacks if not reused after spending. However, the more pressing question revolves around the roughly 6.9 million BTC stored in wallets with publicly exposed keys on the blockchain, including an estimated 1 million coins 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 migration, it could indicate that he is still active, and if they remain stationary, it might be preferable to lock or effectively burn those addresses.
Grayscale presents similar options, including burning the coins, taking no action, or deliberately slowing their release by limiting the spending rate from vulnerable addresses. Nevertheless, the firm notes that the bitcoin community has a history of contentious debates surrounding protocol changes, citing last year's dispute over image data stored in blocks. In contrast, Ethereum faces distinct challenges, with Google's paper identifying five attack vectors worth over $100 billion in combined exposure.
Ethereum Foundation researcher Justin Drake, a co-author of the Google paper, estimated a 10% chance of quantum key recovery by 2032, while the foundation has been staking aggressively, but has not publicly addressed quantum migration timelines.