On Monday, Open Whisper Systemsannounced the release of Signal 2.0, the second version of its app for iOS. What makes this latest release special is that it allows users to send end-to-end encrypted messages, for free, to users of Redphone and TextSecure, Android apps supported by Open Whisper Systems that encrypt calling and text messages, respectively. Previously, this kind of cross-platform secure messaging cost money in the form of a monthly subscription fee, and both the sender and the receiver of the message had to pay. (Or, encrypting m