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Apple Says iOS Kernel Cache Left Unencrypted Intentionally, Nothing To Worry About (loopinsight.com)
The iOS 10 kernel, which Apple released to enthusiasts last week, is not encrypted, according to a report. Security experts expressed their surprise and puzzlement over this in a report by MIT News. The iPhone maker, after remaining tight-lipped over the matter for a week, has now offered an explanation. In a statement to The Loop, Apple said: The kernel cache doesn't contain any user info, and by unencrypting it we're able to optimize the operating system's performance without compromising security.It is worth mentioning that Apple is talking about kernel's cache, whereas MIT News' original report talks about kernel code.
That's actually not how it works. The decryption key is burned into the processor, that is why there is a different firmware image for different versions of the phone. Only some of the phone versions (older ones) have had their keys extracted and released. Also, with new technologies like SGX (shipped in some current desktop CPUs and soon phones) software publishers will be able to write code that can only be decrypted in the hardware's trusted enclave, so the key can never be observed. So stop yelling please when you don't know what you're talking about.
Kernel cache is what they call the encrypted container that has the kernel in it. The article is not wrong, just a nonstandard use of the term.
To be fair, Apple uses a weird terminology with regard to the kernel in iOS (don't know about macs or any other XNU-running devices, don't have any experience with them)
the kernel in iOS is in fact called a kernel cache. It's prelinked, ready to be dumped into memory and executed.
Apple is in fact referring to the kernel when are talking about the kernel cache.
Apple and "security experts" are talking about the same thing.