Some mobile forensics suites can crack locked devices, and Case points to a company called Cellebrite and its Universal Forensics Extraction Device (UFED) as an example of a type of third-party tool that can unlock iPhones.
However, Cellebrite's iOS UFED User Lock Code Recovery Tool, demonstrated in the video below, only works on iOS 7. It essentially exploits a bug in the software that allows the machine to unlock the phone. The iPhone 5C in the San Bernardino case runs iOS 9, which houses much stronger encryption and security measures.
The riskiest option
Finally, the third option would be to physically analyze the iPhone's memory chip and extract its UID as well as any other information needed for offline brute forcing. However, this option is the most difficult of all and is fraught with risk.
"In theory, it's possible to reverse engineer the device itself and get the information," Case says. "But it's difficult, expensive and risky. The slip of a finger, and the information is gone. "
"I don't believe they are going to do that, even if Apple wins and isn't forced to make [the encryption software]," he says. "They won't go that route."
Apple and the government face off on March 22 over a motion that would force Cupertino to comply with a court order demanding it build the custom software. With the backing of the Department of Justice, the FBI may feel confident enough in its case to want to wait before it seriously explores these other, riskier options.
However, depending on how the case plays out - including whether Congress steps in - it may be forced to consider alternative routes and, perhaps, even take them.
Speaking to the situation in general, Case says that the FBI isn't really asking for a special version of iOS, as it's been described, but rather a "specialized custom part" that handles the decryption and the lockscreen. It's "a bit of a stretch on Apple's part" to call it a backdoor, he says, and creating it wouldn't take a lot of work, but "it is pretty dangerous."
"The primary reason is the precedent," he responds when asked why it's dangerous. "[Apple is] going to have every department in the US asking for unlocked phones. Other countries are going to ask for it, too. It's not going to stop at one phone. It's going to put people at risk and data at risk. We know forensic devices have been abused by law enforcement in the past. If they let it go wild, it's going to get abused."
"They can destroy the software they create," he continues, "but somebody else is coming around the corner who will say, 'We have precedent, do it again.'"