According to the US Department of Justice (DOJ) the iPhone is largely uncrackable at this point:
“I can tell you from the Department of Justice perspective, if that drive is encrypted, you’re done,” Ovie Carroll, director of the cyber-crime lab for the CCIPS division of the Department of Justice, said earlier this month during his presentation at DFRWS. “When conducting criminal investigations, if you pull the power on a drive that is whole-disk encrypted you have lost any chance of recovering that data.”
Of course there are a fair number of tools out there for iOS 4 and below including UFED Ultimate and XRY. There is a lack of iOS 5 tools, at least that are being publicly advertised.
However, there’s arguably little need for such a tool anymore. As users put data on in “the cloud”, law enforcement doesn’t even need the physical phone, they can just send a request to Apple (or Google) for the data they want. I suspect this is at least part of what Steve Wozniak was talking about when he mentioned “horrible problems” in the next five years. It’s worth noting Apple has almost zero transparency regarding law enforcement requests and how they are vetted. It’s not even clear a warrant is necessary to request data. The law certainly isn’t clear in that regard.
If anything, I think it’s becoming easier for law enforcement, not harder.