Paradigm'S Pacts Proposal Gives Bitcoin Quantum Hedge

@paradigm general partner Dan Robinson published a proposal on May 1 for a new Bitcoin security mechanism called Provable Address-Control Timestamps, or PACTs. The system lets dormant $BTC holders privately timestamp proof of key ownership before quantum computers arrive, creating a potential rescue path for Satoshi Nakamoto's estimated 1.1 million BTC. The proposal addresses one of the most uncomfortable tensions in Bitcoin's quantum computing debate: how to protect legacy wallets without forcing their owners to reveal themselves.

How PACTs Work

A holder generates a random salt, a piece of secret data used to make a cryptographic commitment unique and unguessable, and uses BIP-322, 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 into an on-chain commitment and timestamped through OpenTimestamps, a free service that anchors data onto the Bitcoin blockchain through a single batched transaction. No public signal is broadcast at any point.

If Bitcoin later activates a soft fork that freezes quantum-vulnerable coins, the protocol could include a rescue path that accepts a STARK proof, a type of zero-knowledge proof that remains secure against quantum computers, showing the holder created their commitment before quantum hardware existed. This redemption process does not disclose any information about the address, amount, or even the original timestamp creation date.

The Satoshi Problem and Broader Stakes

Millions of bitcoin sitting in old wallets with exposed public keys could be vulnerable to theft if sufficiently powerful quantum computers arrive. That includes the roughly 1.1 million bitcoin attributed to pseudonymous creator Satoshi Nakamoto, currently worth around $84 billion. The competing draft, BIP-361 from Casa security chief Jameson Lopp, would phase out quantum-vulnerable addresses on a roughly five-year timeline. Pre-2012 wallets, including most of Satoshi's known addresses, predate the BIP-32 deterministic key standard and cannot use the rescue paths already discussed for newer wallets, leaving PACTs as one of the few options that targets that specific gap.

The proposal does not require Bitcoin to decide today whether a quantum sunset is necessary. It only gives holders a silent, no-on-chain-cost way to preserve evidence that may become useful if such a sunset is ever adopted. No fork is required today. Robinson has been clear, however, that the eventual rescue mechanism would require substantial new infrastructure. While the commitment protocol makes use of well-established primitives like OpenTimestamps, verifying a STARK to allow spending from sunsetted UTXOs will require substantial new plumbing in the Bitcoin protocol. That would itself need a separate soft fork and broad community consensus.

Robinson acknowledged that no guarantee exists that Bitcoin will ever adopt this rescue protocol, and that multisig wallets, complex scripts, and hardware wallet support would each require further standardization before PACTs apply universally. Holders should therefore treat PACTs as a precautionary step rather than a guaranteed protection. The low cost of committing, however, makes early action a reasonable choice for long-term holders.

Sources:
Paradigm: PACTs - Protecting Your Bitcoin From a Quantum Sunset
CoinDesk: New Bitcoin Quantum Proposal Offers Satoshi Nakamoto a Way to Prove Control Without Moving BTC
Bitcoin.com News: Paradigm Researcher Proposes PACTs to Shield Dormant Bitcoin From Quantum Computing Risk