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

Quantum computing concerns have long posed a challenge for Bitcoin, particularly with regards to the vast amounts of bitcoin held in older wallets with exposed public keys, including those attributed to Satoshi Nakamoto, worth around $84 billion. To address this, a proposed soft fork, or upgrade to existing network rules, would eventually stop allowing transactions from these legacy address types, forcing holders to move to quantum-safe formats before attackers can derive their private keys. However, this proposal created a new issue, as dormant holders like Satoshi would have to publicly move their assets or risk losing access to them. To circumvent this trade-off, Dan Robinson of Paradigm has proposed a solution called Provable Address-Control Timestamps, or PACTs, which enables holders to generate a proof of ownership without spending from their wallets. This involves creating a random salt and using a standard for signing messages from a Bitcoin address to produce a proof of ownership, which is then bundled with the salt and timestamped through a free service that anchors data onto the Bitcoin blockchain. If Bitcoin later 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. This proof can be submitted when the holder wants to spend, and the network releases the coins without revealing any information about the original address, amount, or timestamp. The PACTs also address a gap in the existing proposal by including a rescue path for wallets derived through the deterministic key generation standard introduced in 2012. However, the PACTs require Bitcoin to adopt a verification protocol, which would need a separate soft fork with broad community consensus, and the verification infrastructure does not currently exist in Bitcoin. Ultimately, the protocol only protects Satoshi if he, or whoever controls those keys, makes the commitment, and if Satoshi is genuinely gone, no PACT can be retroactively created, leaving the coins exposed to quantum theft or community freeze.