The reason the FBI could get a third party to access the iPhone is because DRM, unlike real encryption such as what is used in Monero, is based on snake oil rather than sound mathematics.
Edit 2: The same or similar Apple DRM that the FBI broke, was used from 2009 to 2014 to censor Bitcoin and is currently used to censor Monero
Are you saying that Apple is lying when it says the user has the private keys and not Apple?
Apple was very disingenuous here.
The iPhone in question used a combination of real encryption and DRM. If the user uses a secure password then the real encryption kicks in and cracking the DRM will not let the investigators in; however if the user follows Apple's recommendation and uses a 4 digit number, as the password, then the real encryption is effectively neutered and only the DRM remains. The user's password controls the key of the real encryption. Apple controls the keys to the DRM.
Apple relied on its proprietary iOS, and keeping the source code of iOS secret (private key 1) to frustrate the investigation. Apple also has a private key (private key 2) that controls what operating system software in installed on an iPhone. It also enforces what software can be installed on an iPhone. The FBI would have been perfectly content with the source code of iOS (private key number 1) and the installation key (private key number 2). This would have made the situation equivalent to someone using GNU PG (Licensed under GPL v3) the very software Edward Snowden used for his leaks. Use GNU PG with a 4 digit number as the password and it can also be trivially cracked. Use it with a secure password and it becomes impossible to crack. The FBI had reason to believe that the terrorist had used a 4 digit number for the password.
Technically one can argue that Apple did not lie, since Apple did not know the 4 digit number that controlled the user key; however since the real encryption was already neutered the only keys that mattered were firmly under the control of Apple.
ArticMine thank you. I learned something new and important. Do you have any citation to backup your claim of Apple's recommend policy of using an insecure password and their DRM?