In an era when email leaks influenced a presidential election and fears of government surveillance are on the rise, even laypeople are starting to take precautions. Open Whisper Systems has no marketing budget and has never placed an ad, but its constantly evolving Signal messaging app, which keeps transmissions secret from all but their recipients, has become so attractive to the general public that it’s got millions of users, and its underlying algorithm has been incorporated into apps used by more than 2 billion people.
“We’re just the weirdos who are interested in doing this, so that’s what we’re doing,” says founder Moxie Marlinspike, an iconoclastic privacy advocate who runs Open Whisper as an open-source project funded by grants and donations, with just a handful of full-time staff and contributions from a loosely knit group of security-conscious programmers around the world. (Edward Snowden is a fan.)
Facebook announced in April that messages sent on the latest versions of WhatsApp would automatically be encrypted with the protocol, and the social networking giant is using it to add a secret messaging mode to its Messenger app as well. Google included the technology in its Allo messaging product, released in September. In addition to security, Signal has recently added features that wouldn’t be out of place in commercial services: It now includes a search tool for GIFs, can sync conversations between mobile and desktop versions, and—naturally—offers messages that automatically disappear after a few seconds.