Silent Circle

Silent Circle is an iOS, Android and Windows suite which lets users make end-to-end encrypted voice calls, texts, and video conferencing. The company is based in the US, and they are upfront about complying to requests made by the US government, if they are reasonable. This means that they may give access to your subscriber data, but no other information, since their privacy policy clearly states that they don’t log anything. The suite costs $120 / year.