Silent Circle phone app will give you a secure line over iOS and Android
The app offers encrypted voice communications, and even eliminates records of calls, texts and emails. The $12.95 monthly charge covers 100 minutes of outbound calls. For $39.95 a month, subscribers get 1000 minutes of secure calling.
Silent Circle is one of the companies behind the Blackphone, a handset introduced at MWC 2014 that automatically provides users with encrypted voice calls, texts and video calls. The phone also protects your files, prevents tracking of your Wi-Fi signal, and won't allow targeted ads to hit the screen.
You can download and install the Silent Circle app for free from the App Store and the Google Play Store, but you need the monthly subscription for it to work on your handset.
source: Silent Circle (iOS|Android) via NewYorkPost