Moxie Marlinspike's TextSecure. https://play.google.com/store/apps/details?id=org.thoughtcrime.securesms&hl= https://play.google.com/store/apps/details?id=org.

Moxie Marlinspike's TextSecure. https://play.google.com/store/apps/details?id=org.thoughtcrime.securesms&hl= https://play.google.com/store/apps/details?id=org.thoughtcri... https://github.com/WhisperSystems/TextSecure/ https://github.com/WhisperSystems/TextSecure/ Pros: Open source, written by someone well established as being both competent and trustworthy. Easy to use. Cons: Android-only. iOS version coming out soon. Uses SMS as transport, but will switch to data channel with release of iOS version.