So Tutanota is working on a post-quantum secure storage offering.
While they have some serious backing in this endeavor, and i applaud their work towards this goal...
They are apparently using the logic that doubly encrypting data with a hybrid approach, using current sound cryptographic methods alongside new post-quantum methods means it's going to be secure regardless in the event that the new methods fail.
The entire reason we need post-quantum cryptography that is sound is because the old methods we use now will not be any longer.
So how exactly does encrypting data with something you know then isn't going to be secure in conjunction with a new method, going to make the new method more secure if and when it fails?
This is some really messed up logic and i'm surprised i'm reading this.
It's like having two locks on your door. The person you are trying to keep out already has the key to one lock. The other lock might be something they can pick. Having two locks isn't useful because one lock is already going to be defeated easily.
The only thing i can consider is that it slows down the time for someone to get in but doesn't prevent it.