Signal is an encrypted instant messaging and voice calling application for Android and iOS. It uses the internet to send one-to-one and group messages. You can include images, videos, as well as make voice calls.
You should use this for your group, text, picture, and video messages. This means that you would use Signal instead of the default messaging apps on your phone.
Encryption is important in your messaging as it secures your information using a protocol called TextSecure that allows users to communicate using voice and text without your information being intercepted.
Unlike many other text messaging products, Signal’s code is open source. That means that experts can regularly inspect and audit the code to ensure that something isn’t happening behind the scenes with your data.
Install Signal on your devices
To get started, follow the Android or iOS guide from the EFF. I also recommend using the Chrome app to message from your browser.
When you install Signal, it will verify your phone number by sending a text message to your device. It will then generate encryption keys for your account. These encryption keys are like an electronic handshake between devices as you chat.
For more information about Signal read this post from The Intercept and this post from Martin Shelton