As per the latest, Google has reached Quantum Supremacy. Meaning it could potentially decode an entire blockchain and...
YOUR PRIVATE KEYS...
Blockchains are secured through elliptic curve cryptography (ECC), just like encrypted user data and website traffic. Now the issue is that ECC is NOT "quantum-safe" meaning that a quantum computer could theoretically decrypt a user's private keys and forge transaction signatures.
Is this the end of Crypto?
I don't think so, but I'd love to hear your opinions too! (Especially the opinion of a cryptographer)
source
https://www.coindesk.com/what-googles-quantum-supremacy-means-for-the-future-of-cryptocurrencyIt would not be an easy ending for bitcoin. On theory, it could crack ones private keys. But researchers of blockchain security are aware of this and started their progress on developing quantum-proof cryptography. If thieves could have access to such computing power in the future, it's no wonder that security would also tighten up for bitcoin as they can also use it to develop more complex algorithms of encrypting private keys. As of now, those leaks mean nothing since we still doesn't see quantum computers in action.