BitMEX Research has proposed a “quantum canary” as an alternative to automatically freezing dormant, quantum-vulnerable Bitcoin.
Under the soft-fork design, the system would create a special Bitcoin address derived from a Nothing-Up-My-Sleeve Number (NUMS) so its private key is intentionally unknown. Users could donate BTC to that address as a bounty. If a quantum-capable actor can actually break the relevant signatures, that actor could spend from the canary address; the act of spending would serve as verifiable proof that the quantum threat is real and would automatically trigger a freeze of coins flagged as quantum-vulnerable.
Crucially, the canary approach does not proactively immobilize old, vulnerable coins. Instead it sets a watch state: vulnerable coins remain spendable under normal rules unless and until the canary fund is spent. Contributors to the canary bounty can protect their donations with multisignature arrangements and may withdraw funds at any time. The proposal also details a grace mechanism that would permit some transactions past the five-year window described in BIP-361, but with outputs time-locked for a period to lower exposure.
This plan was proposed as an alternative to BIP-361, which recommends freezing dormant, quantum-vulnerable coins after a set interval to prevent future theft. BIP-361 prompted significant pushback from parts of the Bitcoin community, with critics arguing such a freeze would be authoritarian or tantamount to confiscation. BitMEX acknowledges that a canary adds complexity and risk but says it may be a less controversial middle ground than an automatic freeze.
Jameson Lopp, a co-author of BIP-361, characterized his proposal as a contingency “rough idea” rather than a ready-to-deploy solution. He has said he dislikes the notion of forced freezes but considers it preferable to the alternative risk of a sudden circulating-supply shock if and when a post-quantum signature scheme is adopted for Bitcoin.
This summary is based on reporting by Cointelegraph. Cointelegraph states it produces news in accordance with its editorial policy and encourages readers to verify information independently.