Developer Bitcoin Core has proposed a defense mechanism against potential quantum attacks. According to this initiative, in case of successful hacking of old Bitcoin wallets by quantum computers, to output 1~BTC from such an address, an additional deposit of 1~BTC for a period of 30 days will be required.
During this period, the legal owner, who has preliminary proof of ownership, will be able to return his funds and withdraw the security of the intruder. It is noteworthy that at the current stage, this concept exists exclusively in the form of a theoretical proposal.