Wickr is a self-destructing messaging app that uses military-grade encryption for texts, pictures, audio, video and PDFs. Unlike WhatsApp or Skype, it’s free to use your own data. Users are anonymous; each message is bound to the device; metadata is cleared from attachments; all deleted files on your phone are deleted. Wickr also has a “Black List” mode so you don’t have to change the default to “White” mode to “clean” your messages.”]