[tzs]

> If you were to encrypt them with the user's Google Accounts password, the device would need to ask for that password on every startup or store the GA password on the device at all times (the latter option is a far greater evil than the current "situation")

If we are just talking about encrypting for backup, then that is not correct. The device would only need to ask for the password before the first backup that includes a wifi password, on the first backup after any wifi password change, and before a restore. Wifi password storage on the device itself can continue to use whatever mechanism it currently uses.

This can actually be cut down to just needing to ask before the first backup and before a restore. Generate a public/private key pair. Ask for the GA password and verify it, and use that to deterministically derive a key to encrypt the private key. Store the public and private keys in the cloud. Cloud data can then be encrypted with the public key before being sent to the cloud.

They only need to ask for the GA password again when they need the private key, such as for restoring the data.

[jordanthoms]

Thing is, this is actually not a one-time backup but an ongoing sync. And it's super convenient - I only have to enter the password on one of my devices and then all the others can connect.

[snom380]

Even with ongoing sync there could be an option to store the password on the device, either permanently or to enter it at boot time. Just like with SSH keys.