Bitcoin Quantum Proposal Introduces PACTs to Protect Old Wallets Without Moving Funds

New PACT System Targets Quantum Risk for Legacy Bitcoin Addresses

A new proposal backed by Paradigm introduces “Provable Address-Control Timestamps” (PACTs), designed to protect older Bitcoin wallets from potential quantum computing threats. The concept allows users to prove ownership of their private keys today without moving funds, addressing long standing concerns about vulnerable legacy addresses.

How PACTs Allow Private Ownership Verification

PACTs enable holders to generate cryptographic proofs of control and timestamp them privately using tools like OpenTimestamps. These proofs remain hidden until needed, preserving privacy while establishing a verifiable claim over funds. If future network upgrades restrict access to vulnerable wallets, users could later unlock their assets using quantum-resistant cryptographic proofs.

Addressing Risks to Satoshi Nakamoto’s Bitcoin Holdings

The proposal is particularly relevant to early wallets, including those linked to Satoshi Nakamoto, which hold an estimated 1.1 million BTC. These coins could be at risk if quantum computers become capable of deriving private keys from exposed public addresses.

Complement to Existing Bitcoin Upgrade Proposals

PACTs offer an alternative to proposals like BIP-361, which suggests phasing out vulnerable address types over several years. While such upgrades could freeze inactive wallets, PACTs introduce a potential recovery mechanism that does not require immediate action or public disclosure.

Implementation Challenges and Limitations

The system would require a future Bitcoin soft fork to integrate STARK-based verification, along with new infrastructure support. However, the solution depends on wallet owners acting in advance—meaning dormant wallets without active key holders may remain unprotected.