This Bitcoin developer's proposal could make quantum hackers lose money when attempting to steal coins.

Author: Jose, Decrypt

Translated by: Chopper, Foresight News

TechFlow Guide: Faced with the future threat of quantum computers cracking early exposed public key Bitcoin addresses, Bitcoin developer Cory Fields has proposed a revolutionary game-theoretic defense mechanism known as the "quantum mine." This design does not rely on radical hard forks or blanket asset freezes, but instead uses game theory to reconstruct on-chain attack and defense costs, forcing hackers to fully stake an anti-quantum bond before attempting to steal coins.

Once the actual holder presents a pre-hidden ownership certificate during the waiting period, the hacker's staked assets will be fully confiscated and awarded to the victim. For dormant coins with lost private keys, a game-theoretic bidding mechanism is introduced to trap attackers in a losing scenario akin to a "dollar auction," cleverly using economic penalties to neutralize the incentive for cryptographic breaks.

Bitcoin developer Cory Fields devised a particularly unique method to counter future quantum hackers: to steal someone else's Bitcoin, a hacker must first bet their own Bitcoin.

He posted about the "quantum mine" concept and two auction mechanisms on the Bitcoin developer mailing list. The core idea of this design is to make attacking vulnerable wallets a potentially money-losing endeavor. He specifically noted that this is merely a thought experiment, not a finalized Bitcoin upgrade proposal.

Bitcoin users initiate transactions by signing with their private keys, while the corresponding public key allows the network to verify the signature without exposing the private key. With current conventional computers, reverse-engineering a private key from a public key is virtually impossible. However, a sufficiently powerful quantum computer could use Shor's algorithm to derive the private key, allowing hackers to directly transfer the coins away.

For some early Bitcoin addresses, public keys are directly exposed on-chain; for others, new addresses also expose public keys when the user makes their first transaction. Therefore, not all wallets face the same risk of quantum attacks. In the industry, the day "a quantum computer capable of breaking Bitcoin encryption enters service" is called Q-Day (Quantum Doomsday). No machine has achieved this yet, and no one knows exactly when it will happen.

How the Quantum Mine Works

Suppose you have 1 BTC in your wallet, belonging to an older type easily vulnerable to quantum cracking. Before Q-Day arrives, you proactively create a tiny, quantum-resistant Bitcoin output containing a hidden proof: demonstrating that even before quantum attacks were feasible, this coin was already yours. You can think of it as a sealed "ownership certificate." Outsiders can only see the small transaction record, unable to see the hidden evidence inside, and may not even know it's a trap.

Later, when a hacker uses a quantum computer to derive your old private key and attempts to transfer your 1 BTC: under these new rules, they cannot simply take the coin outright. They must stake an additional 1 BTC from their own quantum-resistant wallet as collateral.

Your 1 BTC plus the hacker's 1 BTC stake will be bundled and locked together, entering a waiting period for claims (e.g., 30 days). During this time, the hacker cannot arbitrarily move the funds. If you discover someone attempting to steal your coins, you can present the pre-hidden ownership proof. The Bitcoin network will then rule that you can transfer all 2 coins to a quantum-resistant address you prepared in advance (including your original coins plus the hacker's stake).

Hackers have no prior knowledge of which old wallets contain such traps. Even if they successfully derive the private key, they could end up losing their 1 BTC entirely. However, this scheme also comes with trade-offs: if the coin owner themselves wishes to legitimately transfer their old coin after Q-Day, they too must put up an equivalent stake. Without spare BTC on hand, a rule designed to protect against hackers could actually make it difficult for owners to move their own coins.

Game-Theoretic Auctions for Lost and Early Assets

The quantum mine has one prerequisite: the coin owner must plant the trap in advance and present evidence within the claim window. If a private key is permanently lost and the owner can never log in again, this scheme cannot protect those coins, including many early Bitcoins widely believed to be completely lost.

To address this, Cory Fields proposed a second mechanism: a staking auction. Before Q-Day, anyone can lock a portion of quantum-resistant Bitcoin and quietly bid on a vulnerable old wallet likely to be targeted. For example: a wallet seemingly abandoned by its owner contains 50 BTC. When a future hacker tries to transfer it, they must stake 50 BTC as collateral. During the auction window, individuals who placed bets in advance can step forward to challenge the theft attempt.

Under his proposal: the successful challenger can claim a portion of the hacker's stake, while the original 50 risky bitcoins are directly burned rather than awarded to the challenger. Its purpose is not to help the disconnected owner recover the coins, but to prevent hackers from securely stealing them, thereby eliminating the incentive to attack.

The third option is called a Satoshi auction. It requires no upfront locking of coins. Any attempt to transfer high-risk coins automatically triggers a bidding war. The highest bidder wins the coins (minus their bid amount), while the second-highest bidder loses their bid entirely and gets nothing. This resembles the classic "dollar auction game": two parties continuously raise bids for an item, both unwilling to lose money for nothing. Hackers would weigh this and likely decide not to initiate a bid where they are highly likely to lose more.

Why Not a Blanket Freeze Strategy?

One proposed solution is to set a migration deadline, after which all coins in old wallets are banned from being transferred out. While this effectively prevents theft, the side effect is that legitimate holders who forget to migrate or run out of time will have their coins permanently locked.

Cory Fields takes a different approach. Old coins can still be transferred, but any attempt to do so incurs a cost and subjects the transaction to challenges from others. The Bitcoin network itself cannot distinguish between a legitimate owner presenting a valid signature and a quantum hacker.

The trade-offs of this approach are stark: legitimate holders must also prepare large stakes to transfer coins; long-term offline holders might miss claim opportunities; and some holders who are alive but temporarily offline could still see their coins burned in auctions.

Potential Costs and Implementation Pathways

First, Bitcoin needs a quantum-safe method for holding and spending funds. Wallets must support hidden ownership commitments, while Bitcoin consensus rules must enforce collateral requirements, waiting periods, special recovery transactions, and auction mechanisms.

Developers must also reach a consensus on when the new rules will take effect, the required collateral amounts, and how to handle failed bids or remaining funds. Fields believes some mechanisms can be introduced via soft fork, but he has not provided detailed design specifications.

Currently, none of these protective mechanisms exist on the Bitcoin network. Fields also did not provide code implementations, deployment timelines, or finalized allocations for auction funds and ultimate goals in the original text.