Grayscale, a digital asset management firm, has expressed support for expediting efforts to enhance the quantum resistance of public blockchains in a recent research note. The note emphasizes that although technical solutions are readily available, the more daunting task lies in securing agreement among decentralized communities to implement these solutions.
This development follows a week of intense industry response to a paper by Google Quantum AI, which revealed that compromising bitcoin's elliptic curve cryptography would necessitate fewer than 500,000 physical qubits, a substantial reduction from prior estimates, and could be accomplished in approximately nine minutes once the machine is prepared. The paper's findings have significant implications, with CoinDesk's analysis indicating that such an attack would grant an attacker a roughly 41% chance of stealing funds before a bitcoin transaction is confirmed. Grayscale's research highlights four key takeaways from the Google paper, including the potential for progress toward a cryptographically relevant quantum computer to occur in discrete jumps, rendering timelines unpredictable.
Moreover, the technical solutions, specifically post-quantum cryptography, are mature and already securing internet traffic and certain blockchain transactions. The quantum risk varies considerably across blockchains, depending on their transaction model, consensus mechanism, and block time.
From a purely engineering perspective, bitcoin is argued to have a lower quantum risk than other chains due to its UTXO model, proof-of-work consensus, lack of native smart contracts, and specific address types that are not quantum-vulnerable if not reused after spending. However, the more complex issue revolves around the approximately 6.9 million BTC stored in wallets with public keys permanently exposed on the blockchain, including an estimated 1 million believed to belong to Satoshi Nakamoto. Binance co-founder Changpeng Zhao recently posed a similar question, suggesting that if Satoshi's coins are moved during a migration, it would imply that he 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. Nevertheless, the firm notes that the bitcoin community has a history of contentious debates over protocol changes, citing last year's dispute surrounding image data stored in blocks. In contrast, Ethereum faces distinct challenges, with Google's paper identifying five separate attack vectors worth over $100 billion in combined exposure.
Ethereum Foundation researcher Justin Drake estimated a minimum 10% chance of quantum key recovery by 2032, prompting the foundation to stake aggressively, allocating $93 million of ether into validators in a single day. However, the foundation has not publicly addressed quantum migration timelines.