And can Apple guarantee that the ID can't be changed inside the device? If they can't it makes a lot of sense for Apple to refuse creating such a tool.
The ID can be easily changed. A quick Google search will easily confirm this.
The question is can you change one devices ID to exactly match another. This might require hacking the BPP or finding a SHA1 hash collision, both of which are absolutely possible but not necessarily trivial.
Pretty much, as far as I'm aware; the device ID cannot be changed. Bear in mind that this entire discussion is applicable only to older iPhones, in any case.
That guarantee until the latest generation was the only thing protecting the hardware. It has never been altered or hacked that I am aware of. Doing so would require modifying the physical construction of the chips on the device.
Possible? Maybe, but if it was that simple the FBI could simply change the signing key. It's not, and they can't.
