Signal, from Open Whisper Systems, is one of the most highly recommended apps when it comes to chat encryption and security. This app has military grade encryption for all your messaging and voice calls. It supports sending texts, voice calls, group messages, and sending media attachments. Edward Snowden famously recommended this app, which makes it a top pick for people who are looking for security, first and foremost.
The first thing that sets Signal apart from WhatsApp and Allo is that it is open source. The app’s code is freely available for experts to inspect for flaws or back doors in its security. Another thing that makes Signal unique is its business model: There is none. In stark contrast to Facebook and Google, which make their money selling ads, Open Whisper Systems is entirely supported by grants and donations. With no advertising to target, the company intentionally stores as little user data as possible.
Like WhatsApp, all messages sent over Signal are end-to-end encrypted, and Open Whisper Systems doesn’t have the keys to decrypt them. What about message metadata, your phone’s contact list, and cloud backups?