PANews reported on April 16th that, according to a research article published by BitMEX Research, in response to the quantum freeze proposed in BIP-361 (which prohibits sending to quantum-fragile addresses for three years after activation and prohibits spending from quantum-fragile addresses after five years), the authors propose an alternative mechanism: instead of directly freezing after five years, the address enters a "canary observation state." This scheme establishes a special "canary fund" address, generated using a "sleeve digit" system to prove that no one knows the private key. Only when a valid spend occurs on-chain from this address is it proven that a quantum computer capable of stealing Bitcoin exists, at which point the freeze is immediately activated. If the canary is never triggered, quantum-fragile coins can be spent normally. Users can donate Bitcoin to the canary address as a quantum bounty, forming a 1-of-2 multisignature output, and investors can withdraw their Bitcoin at any time. The authors acknowledge that this scheme is more complex than a simple freeze, but considering the significant disruption that a freeze could cause, it is worth evaluating.

Earlier yesterday, it was reported that Bitcoin developers proposed BIP-361, which aims to freeze tokens in addresses vulnerable to quantum attacks .