Messages in iCloud is a clever, though arguably flawed for privacy, feature that keeps all your iMessages in sync, backed up, and restorable to future devices. Delete a photo or entire conversation from one device, it’s gone from all the others.
The major privacy flaw with Messages in iCloud, outlined in Apple’s iCloud security overview, is that enabling this feature essentially renders your messages readable by authorities.
If you use iCloud Backup, a copy of your Messages encryption key is stored in your backups on Apple’s servers. Apple also retains keys to decrypt your iCloud backups. Now, authorities can use various legal means to obtain access to data stored on servers—including your iCloud backups. Bob, as they say, is your uncle.
But does Messages really need iCloud to keep messages in sync, and to bring all your conversations over to a new device? The CPUs in our devices these days do, like, eleventy billion calculations per second. We can use high-bandwidth WiFi to exchange photos and large files between devices with AirPlay (yes, after they first use Bluetooth for local device discovery).
When it comes to the day-to-day of syncing read states and the occasional photo deleted from a chat, couldn’t our devices just work it out directly with each other, no iCloud in the middle? And when it’s time to restore or buy a new device, they already collaborate to exchange a lot of information during setup. Couldn’t our Messages history go along for the ride?
This strikes me as a big potential win for privacy, and possibly a way to reduce complexity of iCloud sync and backup services.