Paradigm researcher proposes timestamp 'escape hatch' to protect Satoshi-era bitcoin from quantum threats

A Paradigm researcher outlined a new model he says could protect dormant bitcoins, including those belonging to the network's creator, Satoshi Nakamoto, from a future quantum computing threat.

The proposal from Dan Robinson introduces what he calls "Provable Address-Control Timestamps," shortened to PACTs. It would create a way for bitcoin (BTC) holders to prove they controlled a wallet before quantum computing advances to the point of being capable of deriving the wallet's private keys — if that day ever comes.

The model uses a timestamping system that is already part of a blockchain's basic functionality. Holders would essentially generate a proof that they control their bitcoin and timestamp it on the blockchain, creating a record of ownership in the event of a future quantum attack. That proof could then later be unlocked, allowing users to reclaim their funds on a future quantum-resistant version of Bitcoin.

It is a potential workaround for a major issue in the quantum bitcoin debate: how to protect the ownership and privacy of long-dormant bitcoin addresses.

Under other similar proposals, like BIP-361 by Casa's chief security officer Jameson Lopp, and others, there would be a multi-year migration window for wallets, exchanges, and custodians to upgrade to quantum-resistant technology, before "sunsetting" legacy signatures. After that period, any coins that failed to migrate would be rendered unspendable.

But this creates a separate set of problems for dormant holders. Moving funds would reveal that the owner is still active and could potentially link the wallet to others they control.

The PACTs model aims to avoid that dilemma by allowing users to prove ownership without broadcasting it onchain.

"This does not require Bitcoin to decide today whether a sunset is necessary," Robinson wrote, adding that it gives users a way to prepare early, letting them "plant a seed now" in case protections are needed later.

The Block reached out to Dan Robinson for comment.

Quantum pressure

As quantum computing advances, crypto users and developers must plan for how to defend against potential threats in parallel.

Lopp and the other researchers behind BIP-361 warned that more than a third of all bitcoins in circulation could be exposed to quantum attacks due to visible public keys.

Meanwhile, real-world demonstrations are starting to show incremental progress. Last week, an independent researcher derived a 15-bit elliptic curve key using quantum hardware in what was described as the largest such attack to date, though Bitcoin relies on stronger 256-bit encryption.

Timelines for "Q-Day," when quantum computers can break modern cryptography, vary depending on who you ask. Google researchers recently suggested a transition to post-quantum cryptography could be needed by around 2029, while others say practical attacks may still be years or decades away.