Proton Mail now supports post-quantum encryption
Privacy Guides Community [Unofficial]
May 5, 2026
I don’t think so. If you go to Settings > Encryption and keys it shows the Email encryption keys and the Account encryption keys, both are updated with the new post-quantum encryption.
Now from my Proton Drive app I can’t upload and sync any file, I get an Invalid manifest signature error.
Discussion in the ATmosphere