TL;DR
Get hardware and tech essentials delivered free with Prime
- Fast, free delivery on millions of items
- Prime Video, Amazon Music and more included
- Member-only deals all year
Bitcoin Core developer Cory Fields has outlined “quantum landmine” ideas that could require a suspected attacker to lock up bitcoin collateral before attempting to spend vulnerable coins. The proposals are thought experiments, not a working Bitcoin feature, and could also impose collateral costs on legitimate holders.
Bitcoin Core developer Cory Fields has proposed “quantum landmines,” a set of hypothetical mechanisms that could make someone attempting to steal bitcoin with a future quantum computer risk putting up their own BTC. The ideas would let owners prepare hidden proof of ownership and, under one example, claim an attacker’s collateral if they reveal that proof during a waiting period. Fields described the proposals as thought experiments; they are not implemented, and depend on quantum-safe wallets and rules that have not been written.
Fields outlined the ideas on Nov. 4 on the bitcoin-dev mailing list. In his example, a person trying to take 1 BTC from a vulnerable wallet would also have to commit another 1 BTC from a quantum-safe wallet. Both amounts would be locked for a period such as 30 days. Before quantum attacks become feasible, the owner could create a separate quantum-safe output containing concealed proof that they control the vulnerable coins.
If a later attacker tries to spend those coins, the owner could reveal the proof during the lockup. The proposed mechanism would then let the owner recover their bitcoin and claim the attacker’s collateral. The attacker would not know in advance which wallets had been prepared as traps, according to the proposal. Fields argued that this uncertainty could discourage attempts, but the deterrent effect is a projected outcome, not an established result.
Fields also sketched a separate auction mechanism for inactive coins whose owners cannot respond, including coins widely attributed to Bitcoin creator Satoshi Nakamoto. In that concept, participants would place hidden bids in advance; an attack could trigger a contract that destroys the targeted coins and awards the attacker’s locked collateral to a winning bidder. The design and its enforcement rules remain unspecified.
Collateral Could Raise the Cost of Attacks
The proposal addresses a difficult choice for Bitcoin developers if quantum computers eventually become capable of deriving private keys from exposed public keys. A mechanism that deters theft could help protect vulnerable holdings, but adding collateral and lockups could also affect legitimate spending. The proposal’s central trade-off is that the network may not be able to distinguish an owner from a thief by intent alone.
Under Fields’s example, an honest holder moving 1 BTC would also need to supply another 1 BTC as collateral. That could make moving vulnerable coins expensive or impossible for people whose wealth is concentrated in an old wallet. The auction idea raises different questions: it could put inactive coins at risk of being destroyed and give bidders a financial interest in triggering the mechanism. These are potential consequences of the sketches, not rules currently operating on Bitcoin.
Products Worth Considering
Trezor Safe 5 Crypto Hardware Wallet with Color Touchscreen, Black Graphite
Trezor Safe 7 Crypto Hardware Wallet
Ledger Flex + Folio Crypto Hardware Wallet
As an affiliate, we earn on qualifying purchases.
Quantum Risk and Vulnerable Keys
A sufficiently capable quantum computer could, in theory, use a wallet’s public key to calculate the corresponding private spending key. Some early Bitcoin transactions exposed public keys from the outset, leaving those coins potentially more exposed than holdings whose public keys have not been revealed. The source report identifies coins associated with Satoshi Nakamoto among the possible targets, but does not establish that they have been compromised.
Bitcoin developers have also debated whether vulnerable coins should be frozen if quantum attacks become practical. Freezing could block a thief but might also prevent an owner who failed to upgrade from spending their bitcoin. Fields’s landmine concepts offer another hypothetical approach: rather than automatically freezing coins, they would use collateral, hidden claims or auctions. They assume Bitcoin first has quantum-safe wallets, which the proposal does not itself provide.
“Because they have no pre-qday proof-of-knowledge of Alice’s key, the attacker would have to wait the 30 days before they can re-spend the output.”
— Cory Fields, as quoted in the proposal
Design and Owner Protections Remain Open
Fields has not published the rules needed to implement or enforce either mechanism, and the proposal is not a deployed Bitcoin feature. The source report does not specify how the network would verify claims, handle disputes, prevent misuse of collateral, or decide when a quantum threat is serious enough to act. It is also unclear how an auction or coin-destruction mechanism could be adopted by the Bitcoin network.
The concepts depend on quantum-safe wallets becoming available and do not protect coins when their owners have lost their keys or cannot make a claim. The source material does not give a timeline for practical quantum attacks. Whether the deterrent would work, how much collateral users would need in real cases, and what protections legitimate holders would receive remain unsettled.
Quantum-Safe Wallets Come First
The immediate prerequisite in Fields’s sketches is the development of quantum-safe wallets. Any landmine or auction system would also need a defined technical design and network rules before users could rely on it. Fields has not set out a schedule for those steps, and the source material does not report a formal adoption process or implementation plan.
Bitcoin developers’ continuing work on quantum defenses and discussions over vulnerable coins may shape whether mechanisms like these receive further consideration. For now, Fields’s post presents possible approaches to a future risk, not a change to how bitcoin can be spent today.
Key Questions
What are the proposed Bitcoin quantum landmines?
They are hypothetical mechanisms in which an owner prepares hidden proof of control over vulnerable coins. A future attacker could be required to lock up bitcoin collateral, which the owner might claim by revealing that proof during a waiting period.
Has Bitcoin adopted the proposal?
No. Fields described the ideas as thought experiments. They have not been implemented, and the rules needed to enforce them have not been written.
Would the mechanism protect every vulnerable bitcoin wallet?
No. The owner-claim version depends on someone retaining the keys and being able to reveal proof. It would not give an owner who lost access to a wallet a way to make a claim.
Could legitimate bitcoin holders also have to provide collateral?
Under Fields’s example, yes. Because the system might not know whether a spender is the owner or an attacker, a legitimate person moving vulnerable bitcoin could also need to lock matching collateral.
When could quantum computers threaten Bitcoin wallets?
The source report gives no timeline for a practical quantum attack. Fields’s ideas assume such a threat could arise in the future, but they do not establish when or whether a capable machine will be available.
Source: coindesk.com
