Quantum Computing May Reveal Satoshi Nakamoto's Status

Adam Back, an early cypherpunk and a figure cited by Satoshi Nakamoto in the Bitcoin white paper, recently suggested that the advent of quantum computing could potentially reveal whether the pseudonymous creator of Bitcoin, Satoshi Nakamoto, is still alive. During an interview following a Q&A session at the “Satoshi Spritz” event in Turin on April 18, Back proposed that the development of quantum computing might compel Nakamoto to move their Bitcoin holdings to protect them, thereby indicating their continued existence.

Back explained that while current quantum computers do not pose an immediate threat to Bitcoin’s cryptography, they could become a significant risk in the future, possibly within the next twenty years. As quantum computing advances, Bitcoin holders will likely need to transition their assets to newer, quantum-resistant signature-based addresses to safeguard their funds. This shift could force Nakamoto to move their Bitcoin if they wish to avoid losing it to potential quantum attacks.

The Bitcoin community will face a critical decision when the threat of quantum computing becomes imminent. They will have to choose between deprecating old, vulnerable addresses or allowing those funds to be stolen. Back anticipates that the community will opt to deprecate the old signatures, thereby forcing Nakamoto to move their funds if they are still in possession of the private keys.

However, the revelation of Nakamoto’s status also depends on the future privacy features of Bitcoin. Back acknowledged that there are research ideas aimed at enhancing Bitcoin’s privacy, which could potentially allow for the resolution of quantum issues while maintaining privacy. This could complicate the process of determining whether Nakamoto is alive based on their actions.

Not everyone in the Bitcoin community shares Back’s perspective. An anonymous early Bitcoin miner expressed skepticism, stating that even if Nakamoto is alive and holds the private keys, they might not move the funds. The miner suggested that Nakamoto’s past behavior indicates a preference for letting the community decide on such matters, and it would be surprising if Nakamoto were to move the assets now.

Back also discussed the technical aspects of implementing quantum-resistant signatures in Bitcoin. He noted that most current implementations are either unproven in terms of security or very data-intensive. Lamport signatures, for instance, are an old and proven design but weigh tens of kilobytes. Back proposed that Bitcoin should be prepared to switch to quantum-resistant signatures but only when necessary, suggesting a taproot-based implementation that allows addresses to transition to quantum-resistant signatures as needed. This approach would ensure that Bitcoin remains secure against quantum threats without compromising its current functionality.