Thorsten Groetker, former Utimaco CTO and one of the top experts in the field of quantum computing said that this worst-case scenario will only happen if warnings are ignored.

Crypto experts not that worried about quantum hacking of bitcoin wallets for a couple of different reasons. Castle Island Ventures founding partner Nic Carter pointed out that quantum breaks would be gradual rather than sudden.

"We would have plenty of forewarning if quantum computing was reaching the stage of maturity and sophistication at which it started to threaten our core cryptographic primitives. It wouldn't be something that happens overnight."

There is also the fact that the community knows that it is coming, and researchers are already in the process of building quantum-safe cryptography.

Fred Thiel, CEO of cryptocurrency mining specialist Marathon Digital Holdings said that the National Institute of Science and Technology (NIST) has been working on a new standard for encryption for the future that's quantum-proof.

NIST is running that selection process now, picking the best candidates and standardising them.

Groetker said: "It's a technical problem, and there's a technical solution for it. There are new and secure algorithms for digital signatures. ... You will have years of time to migrate your funds from one account to another."

Groetker said he expects the first standard quantum-safe crypto algorithm by 2024, which is still, as he put it, well before we would see a quantum computer capable of breaking bitcoin's cryptography. Once a newly standardized post-quantum secure cryptography is built, Groetker said, the process of mass migration will begin.

"Everyone who owns bitcoin or ethereum will transfer their funds from the digital identity that is secured with the old type of key, to a new wallet, or new account, that's secured with a new type of key, which is going to be secure", he said.

There will still be the problem of users who forget their password or died without sharing their key.