New Quantum Proposal Offers Bitcoin Holders a Private Proof of Ownership

The issue of quantum computing has long been a concern for Bitcoin, with millions of coins in old wallets with exposed public keys at risk of being stolen by powerful quantum computers. This includes the approximately 1.1 million bitcoin attributed to Bitcoin's creator, Satoshi Nakamoto, currently valued at around $84 billion. A proposed soft fork, or upgrade to existing network rules, could 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 would require long-dormant holders, including Satoshi, to publicly move their coins or risk losing access to their assets. A new proposal by Dan Robinson, a general partner at Paradigm, offers a way around this trade-off through the concept of Provable Address-Control Timestamps, or PACTs. This involves generating a random salt and using a standard for signing messages from a Bitcoin address without spending from it to produce a proof of ownership. The salt and proof are then bundled together into an on-chain commitment and timestamped through a free service that anchors data onto the Bitcoin blockchain. The protocol could include a rescue path that accepts a zero-knowledge proof, showing the holder created their commitment before quantum hardware existed, allowing them to spend their coins without revealing any information about the original timestamp. This proposal addresses a specific gap in the current freeze proposal and provides a way to make the debate less binary, offering a choice between protecting against quantum theft and respecting dormant property rights.