Novel Bitcoin Quantum Proposal Enables Satoshi Nakamoto to Verify Control Without Transferring Funds

The concern over quantum computing has long plagued Bitcoin, with a particular issue at its core. Millions of bitcoins, including the approximately 1.1 million attributed to Bitcoin's pseudonymous creator Satoshi Nakamoto, currently valued at around $84 billion, are stored in old wallets with exposed public keys, making them susceptible to theft by powerful quantum computers. The obvious solution is a soft fork that would eventually render spends from legacy address types obsolete, forcing holders to transition to quantum-safe formats before attackers can derive their private keys. Prominent developer Jameson Lopp and five other developers proposed a phase-out of quantum-vulnerable addresses over a five-year timeline through BIP-361, which would freeze any coins that fail to migrate. However, this proposal creates a new problem: long-dormant holders like Satoshi would have to publicly reveal themselves or risk losing access to their assets. Dan Robinson, a general partner at Paradigm, has proposed an alternative solution revolving around Provable Address-Control Timestamps, or PACTs. This concept involves generating a proof of ownership at a specific date without publicly revealing any information until the owner needs to spend their coins. A holder creates a random salt and uses BIP-322 to produce a proof of ownership, which is then bundled into an on-chain commitment and timestamped through OpenTimestamps. The salt, proof, and timestamp files remain 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 address, amount, or original timestamp. PACTs address a gap in BIP-361 by including a rescue path for wallets derived through BIP-32. However, 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. This constraint is a significant limitation, as PACTs can only protect Satoshi if he or whoever controls those keys makes the commitment. If Satoshi is no longer present, no PACT can be retroactively created, leaving the coins vulnerable to quantum theft or community freeze. Nonetheless, 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.