Quantum Computing May Challenge Bitcoin's Security, Says Adam Back

According to Cointelegraph, early cypherpunk Adam Back, who was referenced by Satoshi Nakamoto in the Bitcoin white paper, has raised concerns about the potential impact of quantum computing on Bitcoin's security. During a recent interview following a Q&A session at the 'Satoshi Spritz' event in Turin on April 18, Back suggested that advancements in quantum computing could eventually compel Nakamoto to move their Bitcoin (BTC). This is because Bitcoin holders might need to transition their assets to newer, quantum-resistant signature-based addresses to safeguard them. Back emphasized that while current quantum computers do not pose an immediate threat to Bitcoin's cryptography, they could become a significant risk in the future, potentially within the next two decades. He explained that when this threat materializes, the Bitcoin community will face a critical decision: either deprecate old, vulnerable addresses or risk having those funds stolen. Back anticipates that the community will opt for the former, which would necessitate Nakamoto moving their funds to avoid potential loss. The discussion also touched on the role of privacy upgrades in this scenario. Back noted that the revelation of Nakamoto's status might depend on Bitcoin's future privacy features. He mentioned ongoing research that could enhance Bitcoin's privacy while addressing quantum vulnerabilities. However, not everyone agrees that such developments would necessarily reveal Nakamoto's identity. An anonymous early Bitcoin miner expressed skepticism, suggesting that even if Nakamoto is alive and possesses the private keys, they might choose not to move the coins, preferring to let the community decide on the matter. Back further elaborated on the challenges of implementing quantum-resistant signatures, noting that most current implementations are either unproven in terms of security or costly in terms of data requirements. He cited Lamport signatures as a reliable design but pointed out their substantial data size. As a solution, Back proposed that Bitcoin should be ready to adopt quantum-resistant signatures but only when absolutely necessary. He suggested a taproot-based implementation that would allow addresses to transition to quantum-resistant signatures as needed. This approach aims to balance security with practicality, ensuring Bitcoin's resilience against future quantum threats.