Verizon came out with a new "Voice Cypher" OTT app for iOS, Android and Blackberry which sounds like a very cool way to have secure voice communication across mobile networks... until you realize that it has a government backdoor already built in. :-(

http://www.businessweek.com/articles/2014-12-11/verizons-new-encrypted-calling-app-comes-prehacked-for-the-nsa

https://www.verizonwireless.com/wcms/business/apps/voice-cypher.html

http://business.verizonwireless.com/content/b2b/en/solutions/technology/mobile-security/voice-cypher.html