It’s not really a secret; it’s by design and it’s public. iCloud is not end to end encrypted by default. Apple and the state can read the on-by-default iCloud Backup which contains your iMessage sync keys and all your historical iMessages and attachments. iCloud Photos, Contacts, and Mail are all similarly not e2ee and trivially readable by Apple, DHS/FBI, and anyone else under FAA702 (aka PRISM, aka the #1 most used US intel source) without a warrant.

https://www.reuters.com/article/world/exclusive-apple-droppe...

Apple processes FAA702 orders on upwards of 80,000 Apple IDs per year per their own annual transparency report.

Snowden himself said that they see so many nudes that they got desensitized to it.

This clever setup allows them to claim iMessage is e2ee while still escrowing keys in effective plaintext to Apple in the iCloud Backup, rendering the e2ee totally ineffective.

I think “backdoor” is probably an appropriate term for it, but they have made no secret whatsoever of it.

It’s terrifying to think that the US federal government can read every iMessage in the entire world across a billion devices (except China, where the CCP can do the same) in effectively realtime. The power that that enables (if only in blackmail ability) is staggering.