James Comey, the Federal Bureau of Investigation director, said Thursday he was "concerned" over Apple and Google marketing smart phones that can't be searched by law enforcement.

"What concerns me about this is companies marketing something expressly to allow people to place themselves beyond the law," Comey told reporters. He said the bureau has reached out to Apple and Google "to understand what they're thinking and why they think it makes sense."

The move to encryption is among the latest aftershocks in the wake of NSA leaker Edward Snowden's revelations about massive US government surveillance.

Last week, Apple announced the enhanced encryption for iOS 8, which Apple says makes it impossible for the company to decrypt a locked device, even for law enforcement. While Android's encryption was optional, it works similarly. In its upcoming Android L release, encryption will be enabled by default.

Apple chief Tim Cook told PBS News last week that "People have a right to privacy. And I think that's going to be a key topic over the next year or so." When announcing the change, Google spokeswoman Niki Christoff last week said, "As part of our next Android release, encryption will be enabled by default out of the box, so you don't even have to think about turning it on."

Ars' all-knowing Android expert, Ron Amadeo, cautions Android fans. "...if you are looking to keep something safe from prying eyes, Google can reset the pattern unlock on Android devices for law enforcement. Use PIN or Password."

The weak link in the law enforcement scenario for Google and Apple is cloud storage. Companies can and will turn cloud data over to the police, and Google has even done it proactively. Smartphones today have cloud backup systems for just about everything, so while this will probably protect you from individuals trying to snoop in on a stolen or resold phone, there's nothing to stop the police from getting a warrant for data on your phone or for data stored in the cloud connected to your account.