"checksums of file and photo data are used to help Apple de-duplicate and optimize your iCloud and device storage"
This is likely describing content-addressable storage. It is the underpinning of many iCloud services that store user files / blobs. It is also a commonly used pattern in backend services generally.
This is likely describing content-addressable storage. It is the underpinning of many iCloud services that store user files / blobs. It is also a commonly used pattern in backend services generally.
https://en.wikipedia.org/wiki/Content-addressable_storage