Security researchers have a working prototype of an instant messaging application that aims to scrub evidence that two parties have been chatting. The Invisible.im project is looking for developers. It aims to solve a difficult security problem of online messaging services: metadata. Information about other data that can give law enforcement leads on people they’re investigating can be enough to ask a court for warrants. The application is built around XMPP, the widely used chat protocol, which is encrypted using an off-the-record plugin.”]