RedPhone (Android app) and Signal (iPhone app) provides end-to-end encryption for your calls, securing your conversations so that nobody can listen in. RedPhone/Signal uses your normal phone number to make and receive calls, so you don't need yet another identifier. Use the default system dialer and contacts apps to make calls as you normally would. RedPhone/Signal will give you the opportunity to upgrade to encrypted calls whenever the person you're calling also has RedPhone/Signal installed. RedPhone/Signal calls are encrypted end-to-end, but function just like you're used to. Free and Open Source, enabling anyone to verify its security by auditing the code. Uses wifi or data, not your plan's voice minutes. RedPhone and Signal apps are inter-compatible. Signal is on its early stage.