The timeline seems to suggest e2e had always been at the heart of the protocol, but I'm not sure if TextSecure and RedPhone were actually apps that people could

The timeline seems to suggest e2e had always been at the heart of the protocol, but I'm not sure if TextSecure and RedPhone were actually apps that people could install after Whisper Systems was acquired by Twitter. Regardless, instant messaging hadn't seem to be introduced until 2014. Tough call. https://en.wikipedia.org/wiki/TextSecure#/media/File:Signal_timeline.svg https://en.wikipedia.org/wiki/TextSecure#/media/File:Signal_...