[nneonneo]

iMessage seems to use quite a lot of information from the hardware aside from the serial number. See https://github.com/JJTech0130/pypush/blob/main/emulated/data... for the data that is used to calculate the "validation blob" to activate iMessage. Several of the keys (not values!) are random-looking gibberish like "kbjfrfpoJU" and "oycqAZloTNDm", while others are normal things like "product-name" and "IOPlatformUUID".

[turquoisevar]

Those random looking keys are derived from the hardware and together with the values they serve as seeds for some of the keys.

Server-side there’s a bunch more information used from the Apple ID.

Together it results in a score and the server then decides if it meets the threshold before deciding to play nice.