Grayscale, a digital asset management firm, has emphasized the need to expedite efforts to make public blockchains resistant to quantum computing in a recent research note. The note posits that the technical aspects of implementing quantum-resistant solutions are already resolved, but the more significant challenge is securing agreement among decentralized communities to adopt these solutions. This comes on the heels of a recent paper by Google Quantum AI, which found that breaking Bitcoin's elliptic curve cryptography could be achieved with fewer than 500,000 physical qubits, significantly lowering the threshold from previous estimates.
The paper's findings have sparked a wave of industry responses, with CoinDesk's analysis indicating that such an attack could give an attacker a roughly 41% chance of stealing funds before a Bitcoin transaction is confirmed. Grayscale's research identifies four key takeaways from Google's paper, including the potential for progress toward a cryptographically relevant quantum computer to occur in discrete jumps, making timelines unpredictable, and the maturity of post-quantum cryptography in securing internet traffic and certain blockchain transactions.
Furthermore, the research highlights that the quantum risk varies significantly across different blockchains, depending on their transaction models, consensus mechanisms, and block times. 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 the use of certain address types that are not vulnerable to quantum attacks if not reused after spending.
However, the more complex issue is determining the course of action for the approximately 6.9 million BTC in wallets with publicly exposed keys on the blockchain, including an estimated 1 million believed to belong to Bitcoin's pseudonymous creator, Satoshi Nakamoto. This dilemma has also been raised by Binance co-founder Changpeng Zhao, who suggested 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, including burning the coins, taking no action, or deliberately slowing their release by limiting the spending rate from vulnerable addresses.
Nonetheless, 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 its own set of challenges, with Google's paper identifying five attack vectors worth over $100 billion in combined exposure. Ethereum Foundation researcher Justin Drake has estimated a 10% chance of quantum key recovery by 2032, prompting the foundation to stake aggressively in validators, although it has not publicly addressed quantum migration timelines.