Next round of Edward Snowden leaks: "NSA created and funded 'open whisper systems' as a way to get people to think their calls were encrypted when in reality calls went straight to the NSA..."
Their encryption/transfer method has been public for a while and the app is opensource. From what I've read (I'm not technically savvy enough and don't have enough time to actually study it) it shouldn't be possible for them to read your message even if they wanted to. Please someone correct me if I'm wrong.
"Radio Free Asia funds many software projects through its Open Technology Fund." (...) "The Open Technology Fund listed Open Whisper Systems as accepting $455,000 in 2013."
"the Open Technology Fund (OTF) was created in early 2012 from U.S. Government (USG) funds and sustained by annual grants from the Broadcasting Board of Governors (BBG) as a program of Radio Free Asia (RFA)"