[karlshea]

See the iOS Security Guide page 55: https://www.apple.com/business/docs/iOS_Security_Guide.pdf

It sounds like (although I'm not an expert) that it would still be impossible for them to encrypt files in higher data protection classes, since the iCloud backup keys are stored within iCloud Keychain, which is end-to-end encrypted.

Edit: and honestly if I'm misinterpreting that and it's an issue for a specific person, they should just use iTunes encrypted backups and not rely on iCloud.

[comstock]

The statements only refer to:

“When files are created in Data Protection classes that aren’t accessible when the device is locked”

So not photos, most data.