All Android code is available for public review, and plenty of people are reviewing it
It came to light today (though it was never a secret) that the NSA (the National Security Agency), a U.S. intelligence service that's been in the news as of late for things nobody likes, is contributing code to Google's Android project. Of course, the Internet's first reaction was predictably "OMG PRISM! They're building in PRISM!!11one!"
You can relax folks. While the NSA has no official statement about what they call their Security Enhancements for Android project's link to the PRISM project, this isn't something new. They've been working on this Android code since 2011, which is an offshoot of their SE (Security-Enhanced) Linux project before that. Their SELinux code was peer reviewed by anyone and everyone, and the commits were generally accepted as being great additions that make a secure operating system even more safe.
While Android isn't developed in the open, upon release the code is all available. There are all manner of very smart and god-like code nerds pouring through it, and any shenanigans would be quickly uncovered. Let's just take a deep breath, and realize that the NSA could be very helpful writing code to keep systems secure.