New Bitcoin Quantum Proposal Offers a 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, making them vulnerable to theft if powerful quantum computers emerge. This includes the approximately 1.1 million bitcoin attributed to Satoshi Nakamoto, valued at around $84 billion. A proposed solution involves a soft fork that would phase out legacy address types, forcing holders to move to quantum-safe formats. However, this would require long-dormant holders like Satoshi to publicly reveal their assets or risk losing access. To address this issue, Dan Robinson from Paradigm has proposed a concept called Provable Address-Control Timestamps (PACTs), which enables holders to generate a proof of ownership without moving coins. This proof is then timestamped and remains private until the holder needs to spend their coins. The proposal involves using a random salt and BIP-322 to produce a proof of ownership, which is then bundled with the salt and timestamped through OpenTimestamps. 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 approach also addresses a gap in a previous proposal by including a rescue path for wallets derived through BIP-32. However, the implementation of PACTs would 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. Ultimately, PACTs offer a way to make the debate around freezing old addresses less binary, providing a potential solution for protecting against quantum theft while respecting dormant property rights.