New Quantum Proposal Offers Solution for Bitcoin's Satoshi Conundrum

Concerns surrounding quantum computing have long plagued Bitcoin, and a significant issue lies in the fact that millions of bitcoins, including those attributed to Satoshi Nakamoto, are stored in old wallets with exposed public keys, making them susceptible to theft by powerful quantum computers. The estimated 1.1 million bitcoins linked to Satoshi Nakamoto are valued at around $84 billion. One potential solution is a soft fork that would phase out the use of legacy address types, forcing holders to move their coins to quantum-safe formats before attackers can derive their private keys. However, this approach poses a different problem, as dormant holders like Satoshi would need to publicly move their assets or risk losing access to them. In response, Dan Robinson of Paradigm has proposed a concept called Provable Address-Control Timestamps, or PACTs, which allows holders to generate a proof of ownership without revealing any information to the public until they need to spend their coins. This is achieved by creating a cryptographic commitment using a random salt and BIP-322, a standard for signing messages from a Bitcoin address without spending from it. The commitment is then timestamped through OpenTimestamps and remains private. If Bitcoin implements a soft fork that freezes quantum-vulnerable coins, the protocol could include a rescue path that accepts a zero-knowledge proof, showing the holder created their commitment before quantum hardware existed. The holder can then submit this proof when they want to spend their coins, and the network will release the funds without revealing any information about the address, amount, or timestamp. PACTs address a gap in a previous proposal by including a rescue path for wallets derived through BIP-32. However, this solution requires 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 significant development. Ultimately, PACTs offer a way to mitigate the risks associated with quantum computing, but their effectiveness depends on the cooperation of holders, including Satoshi Nakamoto.