Bitcoin developer Cory Fields has proposed a trap that would require anyone trying to steal coins with a quantum computer in the future to risk their own Bitcoin as collateral.
According to CoinDesk, Bitcoin Core developer Cory Fields shared his proposal on the bitcoin-dev mailing list on Wednesday. The design, which he calls “quantum mines,” relies on coin owners preparing a secret proof of ownership before potential attacks; it is not yet a rule implemented in Bitcoin.
Stealing 1 Bitcoin would mean risking 1 Bitcoin
A sufficiently powerful quantum computer could calculate a secret spending key from a public key. Some older Bitcoin whose public keys were visible from the outset could be targets of such an attack in the future.
In Fields’s example, an attacker trying to steal 1 BTC would also have to put up 1 BTC in collateral from a quantum-resistant wallet. The target coin and the collateral would remain locked, for example, for 30 days.
If the coin owner reveals the secret proof they prepared in advance during that period, they can recover their own Bitcoin and also claim the attacker’s collateral. The attacker, meanwhile, cannot tell which coins are protected by such a trap before risking their money.
A separate idea for old and abandoned coins
This mechanism depends on owners who still have their keys preparing in advance. For coins whose keys are no longer accessible or whose owners have become inactive, Fields also proposed an auction design based on secret bids.
Under this idea, participants would submit secret bids in advance for vulnerable coins. If a quantum attack occurs, the winning bidder’s arrangement could burn the target coins and transfer the attacker’s collateral to the winner.
Real owners may also have to find collateral
A major dilemma in the design is that the network cannot distinguish an attacker using a valid signature from the actual owner. Under these rules, someone wanting to move their own 1 BTC might also have to find another 1 BTC in collateral. For users whose entire savings are in an old wallet, this could create additional costs and access problems.
Fields described both ideas as thought experiments. The proposals assume that Bitcoin will first have quantum-resistant wallets; the network rules needed to implement them have not yet been written.
Not investment advice.