In a recent research note, Grayscale, a digital asset management firm, expressed support for accelerating efforts to make public blockchains resistant to quantum computing. The note emphasizes that although technical solutions to achieve quantum resistance already exist, the more daunting task lies in securing agreement among decentralized communities to implement these solutions. This follows a week of intense industry response to a paper by Google Quantum AI, which revealed that breaking Bitcoin's elliptic curve cryptography would require fewer than 500,000 physical qubits, a significant reduction from previous estimates, and could be accomplished in approximately nine minutes once the machine is prepared. Analysis by CoinDesk found that such an attack would give an attacker about a 41% chance of stealing funds before a Bitcoin transaction is confirmed.
Grayscale highlighted four key takeaways from the Google research that they found convincing: progress toward a cryptographically relevant quantum computer may occur in sudden leaps rather than linearly, making timelines unpredictable; technical solutions, specifically post-quantum cryptography, are mature and already securing internet traffic and certain blockchain transactions; quantum risk varies significantly across blockchains depending on their transaction model, consensus mechanism, and block time. From a purely engineering perspective, it was argued that Bitcoin has a lower quantum risk compared to other chains due to its use of a 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 challenging question revolves around the approximately 6.9 million BTC stored in wallets with publicly exposed 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 migration, it would 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, referencing last year's dispute over image data stored in blocks. A notable contrast exists with Ethereum. CoinDesk reported that Google's paper identified five separate attack vectors against Ethereum, totaling 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, who co-authored the Google paper, estimated at least a 10% chance of quantum key recovery by 2032. The foundation has been staking aggressively, placing $93 million of ether into validators in a single day last week, but has not publicly addressed quantum migration timelines.