FAQ: What You Need to Know about Apple’s Encryption Fight with the FBI

Apple’s fight for its right to sell phones with encryption that can’t be unlocked by cops, courts or anybody else got a lot more dramatic this week.

On Tuesday night, a federal judge ordered the company to disable the auto-erase feature on the iPhone 5c used by one of the perpetrators of the mass murder in San Bernardino, Calif. last December.

Apple CEO Tim Cook promptly responded with “Message to our Customers” note on Apple’s site in which he called the judge’s order “an unprecedented step which threatens the security of our customers” and said Apple would resist it.

Since then, the discussion has blown up all over the news. Confused? Here’s what you need to know about the situation.

What does the court want, exactly?

If you’ve read stories saying Judge Sheri Pym wants Apple to decrypt the phone, that’s not quite right. Her three-page order compels the Cupertino, Calif., company to provide “reasonable technical assistance” to disable the security feature in iOS 9 that erases the contents of an iPhone after 10 incorrect attempts to enter its unlock passcode.

If Apple can patch the operating system to disable that feature — something the order suggests would be done by writing a custom software update to be installed on the phone over a USB cable — then investigators could “brute-force” the passcode, one sequence of numbers at a time.

That appears to be the only way to see the contents of the phone used by Syed Rizwan Farook, who with his wife Tashfeen Malik murdered 14 people and injured 22 in the Dec. 2 terrorist attack.

This approach could work on this model, to judge from posts by iOS security experts Dan Guido and Robert Graham, because the iPhone 5c lacks the “Secure Enclave” feature that would reject the proposed patch. A third Mac infosec veteran, Securosis CEO Rich Mogull, concurred with that diagnosis in an e-mail to me.

What does this mean to my iPhone?

Right now, nothing. The government is not demanding that Apple revise iOS altogether to remove the auto-erase feature or provide a permanent backup key for law enforcement (something politicians have requested repeatedly).

Further, your iPhone could not be subject to this kind of brute-force unlocking unless an investigator had already taken it from you. This proposed exploit requires physical access to the phone, not a remote download through the App Store or iOS’s system-update mechanism.

Staging a comparable attack on newer iPhone models “would be much more difficult” but “not impossible” security investigator Jonathan Zdziarski posted in his own analysis of the situation.