Paradigm Proposes PACTs to Counter Bitcoin Quantum Threats
A researcher from Paradigm has introduced a new model designed to safeguard dormant Bitcoin addresses from the potential risks of quantum computing. Known as Provable Address-Control Timestamps (PACTs), this proposal aims to protect wallets that have been inactive for years, including those belonging to Satoshi Nakamoto. The goal is to provide a “safety net” that allows users to prove ownership today without needing to move their funds or reveal their current activity on the blockchain.
How the PACTs Timestamping System Works
The PACTs model utilizes the existing timestamping capabilities of the blockchain to create a permanent record of ownership. Under this system, a holder generates a cryptographic proof of control and anchors it to the ledger. If a quantum computer ever becomes powerful enough to break traditional private keys, this pre-existing timestamp serves as an “escape hatch.” It would allow the legitimate owner to reclaim their assets on a future, quantum-resistant version of the Bitcoin network.
Comparing PACTs with BIP-361 Migration Windows
Other industry proposals, such as BIP-361, suggest a more aggressive approach by enforcing a multi-year migration window. In those scenarios, users would be required to move their Bitcoin to new, quantum-secure addresses before a specific “sunset” date. Any funds not moved by the deadline would become unspendable. However, critics argue that this forces active signaling and compromises privacy. PACTs offer a less invasive alternative, allowing users to “plant a seed” now without forcing the network to commit to a sunset timeline immediately.
The Growing Urgency of Post-Quantum Cryptography
The debate intensified as researchers warned that over one-third of all circulating Bitcoin could be vulnerable due to visible public keys. While current quantum hardware is only capable of breaking small encryption keys, progress is accelerating. Google researchers suggest a transition to post-quantum cryptography may be necessary as early as 2029. Proposals like PACTs ensure that Bitcoin’s most historic and dormant wealth remains secure even as computing power enters a new and potentially threatening era.
