It's not only the recent fight, but the way they implemented it in iPhone 6, with the Secure Enclave. The fact that they created something that is so secure that they cannot hack it themselves blew my mind.
Is there any reading about how this is safe against side channel attacks? My go-to assumption is that any device in the physical possession of an attacker is only as safe as the attacker's motivation X is below the required amount of work Y to do a side channel. I wonder though why the FBI aren't just doing this - is it really not possible for them, or is this all just a bluff to make their targets feel safe using an iPhone?
The FBI is making a court case out of it because they want to obtain legally-binding precedent which will allow them to force companies to make it as easy as possible to access locally encrypted data. If the United States cared enough, they would undoubtedly have the resources to perform any needed attacks themselves. I'd be surprised if the NSA didn't already possess a copy of iOS's source code (Apple was a PRISM participant, which means prior to the Snowden leaks, they were voluntarily transferring all user data to the NSA for analysis; just seems iOS source isn't such a big deal after that).
The FBI is taking this public at a politically opportune time to try to make it so they can order this type of thing for any digital device they physically possess.
There's also a bit of me that thinks the timing is also a convenient way to influence the presidential election. Law enforcement groups are heavily Republican. Encryption has been a topic brought up in the debates. Dems usually say things like "We just need to ask nicely and they'll help us out, I know it"; to your average voter, this is proof-positive that that's not true, and it gives the law-and-order candidates remaining in the GOP field (which, I guess remaining are Cruz and Bush? This would've helped Christie and hurt Fiorina) a very powerful amplifier for their anti-crypto positions.