> And I just don't understand how anyone can maintain that farce when the last year has shown that it's a genuine challenge even for the US FBI to unlock a mobile device without the owners say-so
Difficulty? Yes. But the FBI is not the NSA, they don't specialize in such attacks. It's like asking your plumber to do heart surgery. So they commissioned it to else who does, and boom, they had access.
Strong cryptographic security shouldn't have a pricetag any lower than "we feed all the hydrogen in the universe to black holes to harvest enough energy for the computations".
And phone security is orthogonal to baked-in firmware signing keys. The only change you need is allowing the user to add their own signing keys maybe with the caveat that all data in the protected keystore gets destroyed in the process. Then you have freedom and secure boot in one package.
The signing keys are the issue, not the ring -1 management code.
> If you truly believe that physical access is a trump of any security then you can never trust your hardware anyways, as it is exceptionaly hard to prove it conforms to a spec.
Here are some simple steps
1. compel a manufacturer to create a spy-firmware, signed with their signing key
2. get access to a device for a few minutes
3. patch firmware that exfiltrates the data once the device is unlocked by the user
4. return device to user / to where the user placed it
This is assuming strong encryption keys. If it is only protected by an unlock code your steps look like this.
1. acquire device
2. a) compel manufacturer to create a firmware that bypasses "delete on unlock failure" feature
b) unsolder chips, apply silver needles to flash controllers so you can
read/restore internal key storage whenever it gets wiped
3. enumerate all N-digit pass codes until it is unlocked
As you can see hardware security does not save you when the strong keys are on the device and the user only enters a weak key.
Similarly hardware security does not save you if a hostile entity got access to your hardware.