Google’s ‘Quantum Supremacy’ Isn’t the End of Encryption. As Preskill notes, that contest was uneven. Google carefully chose a problem naturally suited to its quantum hardware and writes in its paper that “technical leaps” are still needed to realize the promise of quantum computing. Dowling and others estimate it would take millions of high-quality qubit devices to threaten encryption, due to the complexity of the algorithms involved.

https://www.wired.com/story/googles-quantum-supremacy-isnt-end-encryption/