New Quantum Proposal Offers Bitcoin Holders a Private Proof of Control

Concerns surrounding Bitcoin's vulnerability to quantum computing have long been tied to the issue of Satoshi Nakamoto's holdings. Approximately 1.1 million bitcoin, valued at around $84 billion and attributed to the pseudonymous creator, sit in old wallets with exposed public keys, potentially vulnerable to theft by powerful quantum computers. The obvious solution is a soft fork that phases out legacy address types, forcing holders to move to quantum-safe formats. However, this approach poses a problem for long-dormant holders like Satoshi, who would have to publicly move their assets or risk losing access. A new proposal by Dan Robinson, a general partner at Paradigm, introduces the concept of Provable Address-Control Timestamps (PACTs), which allows holders to generate a proof of ownership without spending from their wallet. By using a random salt and BIP-322 to produce a proof, holders can create a private commitment and timestamp it through OpenTimestamps, keeping the salt, proof, and timestamp files private. 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. The holder submits this proof when they want to spend, and the network releases the coins without revealing any information about the original address, amount, or timestamp. PACTs address a specific gap in BIP-361 by including a rescue path for wallets derived through BIP-32. However, the protocol requires Bitcoin to eventually 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. Ultimately, PACTs offer a way to make the BIP-361 debate less binary, providing a potential solution that balances protection against quantum theft with respect for dormant property rights.