New Quantum Proposal Offers Bitcoin Holders a Private Proof of Control

The threat of quantum computers to Bitcoin has long been a concern, particularly for holders of coins in older wallets with exposed public keys, including the estimated 1.1 million bitcoin owned by Satoshi Nakamoto, worth around $84 billion. One proposed solution is a soft fork that would phase out the use of vulnerable address types and force holders to move their coins to quantum-safe formats. However, this approach poses a problem for long-dormant holders like Satoshi, who would need to publicly move their coins or risk losing access to them. A new proposal by Dan Robinson of Paradigm offers an alternative, using Provable Address-Control Timestamps (PACTs) to allow holders to privately prove control of their keys without moving their coins. This approach involves generating a proof of ownership and timestamping it on the blockchain, which can then be used to rescue the coins if a soft fork is implemented. The proposal requires the use of a STARK verification protocol, which would need to be implemented through a separate soft fork. While this approach provides a potential solution for holders like Satoshi, it requires them to take action to create the PACT, and does not provide a way to retroactively protect coins if the owner is no longer present.