Once legitimate token holders present previously hidden ownership proofs during the waiting period, the hacker’s staked assets will be fully forfeited and awarded to the victims. For dormant coins with lost private keys, a bidding mechanism is introduced to trap attackers in a guaranteed loss scenario akin to a “dollar auction,” skillfully leveraging economic penalties to neutralize the technical incentive to break in.
Bitcoin developer Cory Fields has come up with a unique approach to combat future quantum hackers: hackers hoping to steal someone else’s Bitcoin must first stake their own Bitcoin as a bet.
He posted on the Bitcoin developer mailing list, introducing the concept of "quantum mines" and two auction mechanisms. The design aims to make attacking vulnerable wallets a potentially loss-making endeavor. He specifically noted that this was merely a thought experiment and not a finalized Bitcoin upgrade proposal.
Bitcoin users sign transactions using their private keys; the corresponding public key allows the network to verify the signature without exposing the private key. On today’s ordinary computers, it is virtually impossible to derive the private key from the public key. However, a sufficiently powerful quantum computer could use Shor’s algorithm to calculate the private key, allowing hackers to directly transfer the funds.
Some early Bitcoin addresses have their public keys directly exposed on the blockchain; additionally, some newer addresses expose their public keys when the user makes their first transaction. Therefore, not all wallets face the same risk from quantum attacks. The industry refers to the day when a quantum computer capable of breaking Bitcoin’s encryption is developed as “Q-Day.” No machine has yet achieved this, and no one knows when it might occur.
Quantum mine operation mechanism
Suppose you have 1 BTC in your wallet, belonging to an older, quantum-vulnerable type. Before Q-Day arrives, you proactively create a small, quantum-resistant Bitcoin output containing hidden proof that you owned these coins before quantum attacks became feasible. Think of it as a sealed "proof of ownership." Outsiders can only see the small transaction record, not the embedded evidence—and may not even realize it’s a trap.
In the future, when a hacker uses a quantum computer to derive your old private key and attempts to transfer your 1 BTC: under this new rule, they cannot simply take the coins—they must first lock up 1 BTC as collateral from their quantum-resistant wallet.
Your 1 BTC, combined with the hacker’s 1 BTC collateral, will be bundled and locked together, entering a dispute period (e.g., 30 days). During this time, the hacker cannot freely transfer the funds. If you discover an attempt to steal your coins, you can present the pre-stored proof of ownership. The Bitcoin network will then verify that you are entitled to transfer all 2 BTC to a pre-configured quantum-resistant address—covering both your original coins and the hacker’s collateral.
Hackers had no idea beforehand which old wallet contained such a trap. Even if they successfully calculated the private key, they might end up losing 1 BTC outright. However, this solution comes at a cost: if the coin’s owner wants to legitimately transfer their old coin after Q-Day, they must also post an equivalent collateral. If you don’t have extra BTC on hand, this rule—designed to protect against hackers—could make it difficult for you to move your own coins.
Auction for lost and early-missing assets
Quantum mines operate on the premise that the coin owner must have previously set up the trap and provide evidence within the dispute window. If the private key has already been lost and the owner can no longer access the account, this solution cannot protect those coins—including many early bitcoins widely believed to be permanently lost.
To address this, Cory Fields proposed a second mechanism: a stake auction. Before Q-Day, anyone can lock up a portion of quantum-resistant Bitcoin and secretly bid on an old wallet that appears vulnerable. For example, if a wallet that seems abandoned contains 50 BTC, a future hacker attempting to move those funds would need to post a 50 BTC security deposit. During the auction window, those who placed early bids can step forward to challenge the theft attempt.
According to his design: those who successfully challenge can claim a portion of the hacker’s collateral; the original 50 risky bitcoins will be permanently destroyed and not awarded to the challenger. Its purpose is not to help the missing owner recover the coins, but to prevent the hacker from safely stealing them, thereby eliminating the incentive to attack.
The third option is called Smart Auction, which does not require pre-locking coins. If anyone attempts to transfer a high-risk coin, an auction automatically initiates. The highest bidder receives the coins (minus their bid amount), while the second-highest bidder loses their money entirely with nothing in return. This resembles the classic “dollar auction” game, where two parties keep raising bids to avoid losing what they’ve already put in. Hackers will think twice and likely avoid initiating an auction that is highly likely to cost them even more.
Why not implement a one-size-fits-all freeze strategy?
The proposed solution is to set a migration deadline; after this date, all coins in the old wallet will be permanently restricted from withdrawal. While this effectively prevents theft, the side effect is that genuine holders who forgot to migrate or failed to act in time will have their coins permanently locked.
Cory Fields took a different approach. Old coins can still be withdrawn, but any attempt to withdraw them incurs a cost and invites challenges from others. The Bitcoin network itself cannot distinguish between the true owner, who can produce a valid signature, and a quantum hacker.
The cost of this trade-off is clear: legitimate holders must post large collateral to transfer their coins; holders who are offline for extended periods may miss the opportunity to appeal; and even some holders who are still alive but temporarily offline may see their coins destroyed in the auction.
Potential Costs and Implementation Pathway of the Plan
Bitcoin first requires a quantum-safe method to hold and use funds. Wallets must support hidden ownership commitments, and Bitcoin’s consensus rules must enforce collateral, waiting periods, special recovery transactions, and auction mechanisms.
Developers still need to agree on when the new rules will take effect, the required amount of collateral, and how to handle failed bids or remaining funds. Fields believes that some mechanisms could be introduced via a soft fork, but he did not provide a detailed design.
Currently, none of these protective mechanisms exist on the Bitcoin network. Fields also did not provide code implementations, a launch schedule, auction fund allocation, or a final objective, none of which were finalized in the original text.
Author: Jose, Decrypt; Translated by: Chopper, Foresight News