PACTs use three steps: a secret salt, a BIP-322 ownership proof, and an OpenTimestamps commitment anchored on-chain, all without any public on-chain transaction.If Bitcoin later implements a quantum sunset soft fork, PACT holders can submit a STARK zero-knowledge proof to reclaim coins while keeping their keys hidden.Robinson wrote that Satoshi revealing keys in any forced migration would mean having to “tell the world that they are alive and still in possession of their keys.”