Bitcoin Core Developer Unveils 'Quantum Landmine' Plan to Penalize Hackers

A Bitcoin Core developer has put forward a concept in which a thief who steals your coins might ultimately have to pay you. That is the idea behind a proposal from Cory Fields.

With Q-Day approaching — the moment when quantum computers become powerful enough to crack Bitcoin's existing encryption — Fields aims to make the theft of at-risk coins a risky proposition for attackers.

On November 4, Fields shared his "quantum landmines" concept on the Bitcoin Development Mailing List. The mechanism is straightforward: Bitcoin holders could covertly set traps that would penalize hackers in the future.

How Could a Bitcoin Thief End Up Losing Their Funds?

Suppose you hold 1 BTC in a legacy wallet that is susceptible to quantum attacks.

Prior to Q-Day, you could embed a concealed ownership proof within a small quantum-resistant Bitcoin output. That proof remains invisible to everyone else.

• Hackers would have to put up Bitcoin to take Bitcoin: According to the proposed framework, when quantum attacks are feasible, any party trying to transfer that vulnerable 1 BTC would need to deposit an additional 1 BTC as security. Both sums would then enter a waiting period, possibly lasting 30 days.
• Hackers might succeed in stealing, but you could retrieve your coins: In the event a quantum attacker takes your Bitcoin, you could disclose your hidden proof within the waiting period, reclaim your BTC, and also take the hacker's collateral.

The attacker would suffer a financial loss. You could end up with double the amount you originally had.

Fields argues that attackers would become “wary of stealing coins as they may be secretly guarded by mines.”

However, a Significant Drawback Exists for Bitcoin Owners

Since the blockchain has no way to tell a hacker apart from a genuine owner, anyone transferring at-risk Bitcoin would be subject to the same collateral condition.

A person with 10 BTC in an outdated wallet could require an extra 10 BTC in quantum-proof coins just to shift their funds.

An additional issue arises with dormant Bitcoin, such as coins from the Satoshi era.

When private keys are missing, no one can set a landmine. Fields suggests other auction-based systems where participants could contest hackers and take their collateral. One variant involves permanently eliminating the at-risk coins.

This situation raises tough issues regarding ownership and Bitcoin's total supply.

At present, the discussion highlights a challenging compromise: safeguarding Bitcoin against future attackers might make transferring older coins significantly costlier for rightful owners.