New Bitcoin Quantum Proposal Offers Solution for Proving Control Without Moving Funds

Concerns over quantum computing have long plagued Bitcoin, with millions of coins in old wallets having exposed public keys that could be vulnerable to theft by powerful quantum computers, including the approximately 1.1 million coins attributed to Bitcoin's creator, Satoshi Nakamoto, valued at around $84 billion. A proposed soft fork to phase out quantum-vulnerable addresses over five years, forcing holders to move to quantum-safe formats, has been put forward by prominent developer Jameson Lopp and five other developers through BIP-361. However, this proposal poses a problem for long-dormant holders like Satoshi, who would have to publicly move their assets or risk losing access to them. To address this issue, Dan Robinson of Paradigm has proposed a solution called Provable Address-Control Timestamps (PACTs), which enables holders to timestamp proof of ownership without moving coins or revealing any information publicly until they need to spend. The process involves generating a random salt and using BIP-322 to produce a proof of ownership, which is then bundled with the salt and timestamped on the Bitcoin blockchain through OpenTimestamps. The salt, proof, and timestamp files remain private, and if Bitcoin activates a soft fork that freezes quantum-vulnerable coins, the protocol could include a rescue path that accepts a STARK proof showing the holder created their commitment before quantum hardware existed. This solution also addresses a gap in BIP-361 by including a rescue path for wallets derived through BIP-32. However, the PACTs require Bitcoin to adopt a STARK verification protocol, which would need a separate soft fork with broad community consensus. The verification infrastructure does not currently exist in Bitcoin and would require substantial new development, including multisig wallets, complex scripts, and hardware wallet support. Ultimately, the protocol only protects Satoshi if he or whoever controls those keys makes the commitment. If Satoshi is genuinely gone, no PACT can be retroactively created, leaving the coins exposed to quantum theft or community freeze. The PACTs offer a way to make the BIP-361 debate less binary, providing a choice between protecting against quantum theft and respecting dormant property rights, but whether Satoshi will use it remains uncertain.