

The rise of end-to-end encryption, which means the content of messages can only be read by the sender and receiver, not the company offering the service, is known to frustrate law enforcement agencies. In March last year, it added a secure video-call option and five months later announced Signal for desktop. Since launching in 2014, Signal has added numerous new features. It received a glowing security audit in November 2016 from independent analysts at the International Association for Cryptologic Research. The protocol developed by its parent company, Open Whisper Systems, has been integrated into other apps including Facebook Messenger and WhatsApp. #notesforFBI (Spoiler: they already know) - Edward Snowden November 2, 2015
