Very cool app. Allows you to communicate securely over your Android cell phone.
How to Use RedPhone for Android
Forget tin-foil hats, burner phones and payphones as means to avoid prying ears. RedPhone is an app for Android that enables secure phone calls on smartphones. It encrypts the communication between callers so that anybody listening in would only hear static, not the conversation. If you need to make an important phone call that you wouldn’t want somebody to intercept, RedPhone is a great option.
RedPhone lets users make calls using VoIP or Voice over IP which means that instead of using phone lines, voice calls are done over an internet connection in the same way that a call using the Google Voice app does. Unlike Google Voice, RedPhone conveniently uses your normal cell phone number making it a friendly and free way to keep your private conversations private.