Overview
- Paradigm’s Dan Robinson unveiled PACTs, a method that lets dormant Bitcoin holders record proof of control now in case future rules restrict spending from older keys vulnerable to quantum attacks.
- PACTs work off-chain by combining a secret salt, a BIP‑322 signed message that proves address control, and an OpenTimestamps anchor, so holders create evidence without moving coins or revealing which address they own.
- If Bitcoin later enacts a “quantum sunset” that freezes exposed public keys, a holder could present a post‑quantum zero‑knowledge proof such as a STARK to reclaim funds, which would require a soft fork and new on‑chain verification logic.
- Robinson pointed to high‑stakes dormant balances, including wallets believed to belong to Satoshi Nakamoto with about 1.1 million BTC, while separate reporting estimates roughly 1.7 million BTC sit in address types seen as exposed.
- The proposal enters an active debate that includes BIP‑361’s phased migration and freeze plan and pushback from voices like Blockstream’s Adam Back favoring opt‑in upgrades, and Robinson stresses PACTs are preparatory only with no guarantee of adoption.