[StavrosK]

How do we even know that the backups aren't encrypted? For all I know, the author had a second iDevice and it shared the key with the first one when the latter came online. That way, the key never leaves your devices, but you can still sync your messages.

Is there a way to access the messages on iCloud itself (i.e. the web interface)? That would be much stronger evidence that Apple can read it.