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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.
Is the new iOS running on Apple's new filesystem? Supposedly part of the features of the new filesystem is that it has greater control over file encryption. Given this explanation, it may be that they previously encrypted the kernel because it was the best way to encrypt user data, whereas with a new filesystem they may be able to encrypt the files they want to encrypt without needing to encrypt anything else.
Just a shot in the dark, though.