3 ms·

My understanding is that the serials represent information, including model and date/location of manufacture. It’s therefore possible to create correctly formed

My understanding is that the serials represent information, including model and date/location of manufacture. It’s therefore possible to create correctly formed but impossible serials, for example one that represents a pre-touchbar 2015 MBP manufactured in Ireland in 2018. Apple should easily be able to tell when someone has done this.

turquoisevar 3y ago
They indeed used to have data like that encoded in it. Not too long ago, however, they moved to a completely randomized serial format, perhaps partly because of iMessages shenanigans.
- rezonant 3y ago
  Hmm, how many bits of entropy are in one of these things? Can we calculate the likelihood of collision?
- nneonneo 3y ago
  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.plist 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 3y ago
    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.