Bitcoin Core developer Cory Fields has proposed three conceptual mechanisms — Quantum Landmines, Staked Auction and Sats Auction — aimed at protecting legacy Bitcoin holdings from future quantum-enabled theft. Presented as thought experiments in a proposal on post-quantum Bitcoin migration, the framework would require collateral whenever legacy BTC is spent once quantum attacks become feasible, and would open ways for existing holders and third parties to claim attackers' collateral.

Quantum Landmines would let existing owners establish cryptographic ownership proofs and claim attackers' collateral through a 30-day transaction lock, while Staked Auction and Sats Auction introduce bidding mechanisms in which participants compete for vulnerable BTC using quantum-safe collateral.

Quantum Landmines Could Protect Legacy Bitcoin

Fields' framework assumes that developers will introduce quantum-safe outputs before quantum attacks become practical. The concern traces to the elliptic-curve signatures securing legacy outputs: Shor's algorithm, run on a sufficiently capable quantum computer, could derive private keys from exposed public keys, which is why quantum-safe outputs would instead use signature schemes designed to withstand such attacks. Once that point is reached, spending legacy Bitcoin would require full collateralization along with additional conditions, which could include time locks and alternative spending paths enforced through new network rules.

Quantum Landmines would rely on a commit-reveal scheme to establish ownership before quantum threats emerge. Owners would embed a cryptographic proof in a small quantum-safe output ahead of time. If an attacker later spends vulnerable BTC, the transaction would remain locked for 30 days, giving the original owner a window to reveal the earlier proof and claim the attacker's collateral.

Staked Auction Introduces Precommitted Bids

The Staked Auction concept addresses vulnerable coins whose private keys their owners may have lost. Participants would stake quantum-safe BTC before quantum attacks become possible, with commitments identifying vulnerable outputs, bid amounts and replacement public keys. After an attacker spends the targeted coins, the auction would allow participants to claim the collateral.

Fields illustrated the mechanics with an example: a holder could stake 50 BTC and commit to a 40 BTC bid, while another participant could later submit a lower 30 BTC bid. The auction would continue until its second timeout expires. He outlined several possible rules, including collateral burning, penalties for losing bids and payments to miners.

Sats Auction Could Draw Outside Bidders

The third proposal, Sats Auction, removes the requirement for advance staking. Instead, every legacy coin spend would trigger an auction after an initial timeout. The highest bidder would receive the vulnerable coins minus their bid, while the second-highest bidder would lose their payment without receiving anything in return.

Fields discussed the concept with Neha Narula of MIT's Digital Currency Initiative, who suggested drawing on the Dollar Auction game — a scenario in which escalating bids can leave participants paying more than the prize is worth. He has not selected a preferred design, and all three mechanisms remain conceptual. As the proposal was posted to Bitcoin's public development mailing list, any evolution into concrete consensus rules would surface through that same open review process.