New Proposal Offers Bitcoin Holders a Way to Prove Ownership Without Exposing Themselves to Quantum Computing Risks

The threat of quantum computing to Bitcoin has long been complicated by the issue of dormant holdings, including those of its creator. Millions of bitcoins, including approximately 1.1 million attributed to Satoshi, are at risk due to exposed public keys. The standard solution, a soft fork to phase out vulnerable address types, poses a dilemma for long-dormant holders like Satoshi, who would have to publicly move their assets to avoid loss. A new proposal by Dan Robinson of Paradigm introduces Provable Address-Control Timestamps (PACTs), enabling holders to timestamp proof of ownership without revealing their identities until they choose to spend their coins. This involves generating a unique cryptographic commitment and anchoring it to the Bitcoin blockchain through OpenTimestamps, keeping all related data private. If Bitcoin implements a soft fork that freezes vulnerable coins, PACTs could provide a rescue path using zero-knowledge proofs, allowing holders to spend their coins without exposing their address or the timing of the original timestamp. While PACTs address a critical gap in existing proposals by including a rescue path for wallets derived through older standards, they require the adoption of a STARK verification protocol, which would necessitate a separate soft fork and significant infrastructure development. Ultimately, PACTs offer a potential middle ground in the debate over protecting against quantum theft while respecting the rights of dormant holders, though their effectiveness depends on the proactive participation of holders like Satoshi.