This is possible now (in one direction, so far).

However,

> Unfortunately, it’s still not possible to migrate your chat history [from iOS] to a different Android phone, but WhatsApp is planning this in the future. It’s also not possible to migrate your chat history from Android to iOS right now.

I would be surprised, given everything happening in the world today, if the new system does not somehow allow law enforcement to get access (possibly indirectly, through the app giving the key in some weird back channel)

Definitely was not E2EE before.

Whereas ... after that change, Google can read your messages, hackers/law-enforcement only need to talk to Google, and yet -- you yourself can't get that backup without impersonating the WhatsApp app to Google Drive; The local backup is still encrypted with a key that only Facebook knows (and would give you, but only if you impersonate the WhatsApp app when talking to Facebook).

I've looked for the logic and failed. Only reasons I can find is that FB wants to let Google index your messages behind your back (unlikely) or some plausibly deniable legal backdoor.

https://www.theverge.com/2020/12/17/22180258/google-whatsapp...

https://www.theverge.com/2020/12/17/22180258/google-whatsapp...

I am only reachable via email and Signal. I got my contacts to switch to Signal.

You're right that "E2E" is slightly ambiguous. But "encryption at rest" is even worse in my opinion, since it could just mean that Apple/Google's datacenters have disk encryption with a key they can access.

But from my understanding, "encryption at rest" is not disk encryption.

If you have a database with disk encryption, once the disk crypto key is entered an attacker could try to "do hacker stuff" and exfiltrate the WAL files.

If you have "encryption at rest", the WAL files are written encrypted and are decrypted on read. An attacker may get your WAL files, but they are still encrypted.

>Encryption at rest is designed to prevent the attacker from accessing the unencrypted data by ensuring the data is encrypted when on disk. If an attacker obtains a hard drive with encrypted data but not the encryption keys, the attacker must defeat the encryption to read the data.

https://docs.microsoft.com/en-us/azure/security/fundamentals...

So with this definition encryption at rest has the threat model of an attacker who can physically steal a hard drive but not the hard drive's encryption key.

I was referring to the prior backup scheme where Facebook wasn't encrypting. It could accurately be described as encrypted at rest I think, but yet Google and Apple could read the contents I think.

>no ends and it is just a loop.

The terminology is getting pretty confusing at this point. I usually think of the ends as the intended parties to look at the data. If there are no ends, then no one will look at the data, meaning the data is useless. Actually if there's no beginning end, there's no one to create the data, so thus the data doesn't even exist.