The United States Department of Justice (DOJ) has hit back at claims made by Apple since it was ordered last month by a US magistrate to help the FBI gain access to the phone of one of the San Bernardino shooters.
In recent weeks, Apple executives have said the case could set a precedent to allow government surveillance to turn on the microphone and camera of a smartphone; that the FBI is taking the side of hackers and turning the clock back to the security standards of 2013; and that the order is compelling Apple to create a backdoor for its own software.
Writing in a brief filed with the District Court for the Central District of California, the DOJ said Apple's complaints -- over the burden placed upon it to create a version of iOS to bypass functionality that auto-erases a device once a number of failed passcode attempts is reached -- are of its own making.
"This burden, which is not unreasonable, is the direct result of Apple's deliberate marketing decision to engineer its products so that the government cannot search them, even with a warrant," it said.
The DOJ said Apple's rhetoric is false and corrosive to the courts, the Fourth Amendment, and ultimately the government itself.
Arguments put forward by the DOJ in its brief dismissed concerns by Apple that once the backdoor is created, it would find its way beyond the limitations of the single iPhone 5C in question.
"Contrary to Apple's stated fears, there is no reason to think that the code Apple writes in compliance with the order will ever leave Apple's possession," the DOJ said.
"Nothing in the order requires Apple to provide that code to the government or to explain to the government how it works. And Apple has shown it is amply capable of protecting code that could compromise its security."
The DOJ cited Apple's protection of its operating system source code and the key it uses to sign its software as examples of software that Apple is capable of protecting.
"Those -- which the government has not requested -- are the keys to the kingdom. If Apple can guard them, it can guard this."
A combination of Apple's electronic signature and using the unique ECID identifier from the iPhone the FBI has in its possession, should be enough to prevent the software from running on other iPhones, the DOJ said.
"If the code were modified to run on a phone with a different ECID, it would lack a valid digital signature. Without that signature, the code would not run at all on any iOS phone with intact security.
"Thus, it is simply not plausible that Apple's complying with the order would cripple iPhone security."
A counter-argument put forward by Apple has been that once the US is able to compel Apple to create a custom iOS version, other countries would soon look to compel it in the same way. The DOJ dismissed this argument, citing Apple's dealings with the Chinese government.
"The pressure of foreign law on Apple flows from its decision to do business in foreign countries, not from the order," the brief said.
"If Apple can provide data from thousands of iPhones and Apple users to China and other countries, it can comply with the AWA [All Writs Act] in America.
"This is not speculation because, in fact, Apple complied for years with American court orders to extract data from passcode-locked iPhones, dedicating infrastructure and personnel in order to do so.
"It never objected or sought compensation. Apple can handle, and has handled, this burden."
The Department of Justice argued that Apple's control over its devices after they have been purchased means the company has a continued connection to its devices, and that it is not sufficiently removed to have the court order waived.
"Apple intentionally and for commercial advantage retains exclusive control over the software that can be used on iPhones, giving it monopoly-like control over the means of distributing software to the phones," the DOJ said.
"Having established suzerainty over its users' phones -- and control over the precise features of the phones necessary for unlocking them -- Apple cannot now pretend to be a bystander, watching this investigation from afar."
Apple has dismissed the government's claims as an attempt to smear the other side with false accusations and innuendo.
"We work shoulder to shoulder with [the FBI] all the time," said Bruce Sewell, Apple general counsel. "That's why this cheap shot brief surprises us so much.
"I can only conclude that the DOJ is so desperate at this point that it's thrown all decorum to the winds."