Signal Messenger, WhatsApp, and Privacy
Signal Secure Messenger Signal is a secure messenger app published by the Signal Foundation and Signal Messenger LLC. These are not-for-profit organizations based in Mountain View, California. They were founded by Matthew Rosenfeld aka ‘Moxie Marlinspike’ and Brian Acton, to build on the work of one of Rosenfeld’s earlier start-ups Open Whisper Systems. Signal is free and open source. One of the glories of open source is that absolutely anyone can review the source code.