Grayscale, a digital asset management firm, has released a research note advocating for expedited efforts to enhance public blockchains' resilience against quantum computing threats. The note posits that although technical solutions to mitigate these risks already exist, the more daunting task lies in securing agreement among decentralized communities to implement these solutions.
This comes on the heels of a recent paper by Google Quantum AI, which suggests that breaking Bitcoin's elliptic curve cryptography could be achieved with fewer than 500,000 physical qubits, a 20-fold decrease from prior estimates, and could be executed in approximately nine minutes. The study by Google Quantum AI has sparked a flurry of responses within the industry.
CoinDesk's analysis indicates that such an attack would afford an attacker a roughly 41% chance of pilfering funds prior to the confirmation of a Bitcoin transaction. The research note by Grayscale highlights four key takeaways from Google's findings that they find compelling. Firstly, progress toward developing a quantum computer with significant cryptographic implications may occur in abrupt leaps rather than in a linear fashion, rendering timelines unpredictable.
Secondly, technical solutions, specifically post-quantum cryptography, are mature and are already being utilized to secure internet traffic and certain blockchain transactions. Thirdly, the quantum risk varies substantially across different blockchains, contingent upon their transaction models, consensus mechanisms, and block times.
Lastly, from a purely engineering perspective, Bitcoin is argued to have a lower quantum risk compared to other chains due to its UTXO model, proof-of-work consensus, lack of native smart contracts, and specific address types that are not vulnerable to quantum attacks if not reused after spending. However, the more complex issue revolves around addressing the approximately 6.9 million BTC held 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 query, suggesting that if Satoshi's coins were to move during a migration, it would imply that Satoshi is still active, which is an intriguing prospect, and if they do not move, it might be preferable to lock or effectively burn those addresses. Grayscale presents the options in a similar light – burning them, 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, pointing to the dispute last year surrounding image data stored in blocks. In contrast, Ethereum faces a distinct set of challenges. CoinDesk reported that Google's paper identified five separate attack vectors against Ethereum, totaling over $100 billion in combined exposure, affecting account keys, admin keys on stablecoins, smart contract code, consensus mechanisms, and data availability. Justin Drake, a researcher at the Ethereum Foundation who co-authored the Google paper, estimated a minimum 10% chance of quantum key recovery by 2032.
The foundation has been actively staking, allocating $93 million of ether into validators in a single day, but has not publicly addressed timelines for quantum migration.