TPM did not get key from nowhere. The key need to come from network or locally generated as long as it is not preloaded when manufacturing. And in either way, it should be possible to intercept/fake it.

Apple devices with a secure enclave have the ability to attest to their identity, and also attest that keys were generated on a secure enclave (this functionality is very locked down for privacy preservation purposes, but is certainly available to Apple). If Apple is willing to lock out any device shipped without a secure enclave (which would probably be an excessive number of Macs at the moment - the iMac only started shipping with a T2 in the 2020 model, although the iMac Pro did have a T1 earlier than that) then it's absolutely possible to restrict access to actual Apple hardware with no risk of key interception.

> as long as it is not preloaded when manufacturing

which is exactly what happens

It's only a matter of time until a company starts selling TPM dumps, right?

You can't "dump" a TPM. That's the whole point. They are designed such that the cryptographic secrets they hold (including ones loaded at manufacturing) are unrecoverable without an electron microscope and nation-state level resources (and even then, it would be extremely difficult if not impossible on modern process nodes).

> You can't "dump" a TPM.

> unrecoverable without an electron microscope and nation-state level resources (and even then, it would be extremely difficult if not impossible on modern process nodes).

Oh, so you can. It's only a matter of time.

Even with an electron microscope you wouldn't extract a root key it would just be a device key which they would then ban.

There's plenty that one would be able to do with a device key before it is banned.

maybe, but for a task like this it doesn't really scale

Apple aren't going to allow one phone to attest 5000 new iMessage clients

That's... amusingly, also a thing in Chinese marketplaces, for a similar purpose.

iCloud Activation Lock, on non-cellular devices (eg, Wi-Fi only iPads), relies on the device's serial number, Wi-Fi MAC, and Bluetooth MAC addresses as the three identifiers required to clear the Activation Lock check. Via special debug cables (eg, a "DCSD cable") there are ways to write in new SysCfg data to the flash to change those variables. This can also be done to Apple Watches (pre-Series 6) with a special dock also sold on the Chinese market.

You can (sort of easily) get your hands on a "clean" serial/MACs set for under $10-15 or so on the market.

Interesting. I assume this is mostly used to "wash" stolen devices to make them appear legitimate for resale? I'm surprised Apple designed the hardware to allow this without any sort of authentication.