New Bitcoin Proposal Offers Alternative Solution for Proving Control Over Vulnerable Keys

Concerns surrounding Bitcoin's vulnerability to quantum computing have long been intertwined with the issue of Satoshi Nakamoto's holdings. Approximately 1.1 million bitcoin, valued at around $84 billion and attributed to the pseudonymous creator, remain in old wallets with exposed public keys, making them susceptible to theft by powerful quantum computers. The straightforward solution involves a soft fork that would eventually disallow transactions from these legacy addresses, forcing holders to transition to quantum-safe formats before potential attackers can derive their private keys. However, this approach poses a dilemma for long-dormant holders like Satoshi, who would have to publicly move their assets or risk losing access to them. Dan Robinson of Paradigm has proposed an alternative solution, known as Provable Address-Control Timestamps (PACTs), which allows holders to generate a proof of ownership without spending any coins. This is achieved by creating a unique cryptographic commitment using a random salt and BIP-322, then timestamping it through OpenTimestamps without revealing any information publicly. If a soft fork that freezes quantum-vulnerable coins is implemented, the protocol could include a rescue path that accepts a zero-knowledge proof, demonstrating the holder created their commitment before the existence of quantum hardware. This approach addresses a specific gap in a previous proposal by including a rescue path for wallets derived through BIP-32. However, the implementation of PACTs requires the adoption of a STARK verification protocol, which would necessitate a separate soft fork and substantial new infrastructure. Ultimately, the success of PACTs in protecting Satoshi's holdings depends on whether the creator or current controller of those keys takes the necessary steps to create a commitment. If Satoshi is indeed inactive, no PACT can be retroactively created, leaving the coins vulnerable to either quantum theft or community freeze.