There is a sudden surge of interest in the messaging app Signal. Even uncles and aunts who prefer WhatsApp for “good morning” messages are turning to Signal to see if greetings can be spruced up. Signal is in the spotlight after top officials in the Donald Trump administration discussed sensitive military planning using the unclassified chat application that mistakenly included a journalist named Jeffrey Goldberg, the editor in chief of The Atlantic magazine. Here’s all you need to know about the messaging platform.

What is Signal?

It’s a messaging app that can be installed on the iPhone or Android phone or on your computer. The app lets users send secure texts, images and phone or video chats with other people or groups of people, just like iMessage, Google Messages, WhatsApp and other chat apps. The installation process hardly takes two minutes and is designed to work like other texting apps.

What makes it private?

Signal is operated by a non-profit called the Signal Technology Foundation. The process of sending messages is similar to other apps. There are no ads or trackers on Signal, and you can set messages to disappear after a certain amount of time, from as little as 30 seconds to as long as four weeks.

What makes communications on Signal special is that they are end-to-end encrypted by default, meaning the data is scrambled in transit and can only be seen by the sender and recipient. Not even Signal can access the content of messages or calls. The app can’t even see display names or profile pictures, according to its privacy policy and support page.

To make it secure, message history is stored on a user’s device and not on Signal’s servers. But it is possible to queue messages on its servers to be delivered later for devices that are temporarily offline.

There is a feature called “safety number” or a code that gets assigned to an individual to help verify messages are going to the intended recipient. It is the combination of privacy features that make Signal special.

Signal stores only two pieces of information about its users — when they created their Signal account and when they last used the app. It is popular among journalists, politicians, business folks, activists and people who are privacy-conscious.

Why use Signal over other text apps?

The app is far more secure than most messaging platforms. Unless you add someone you didn’t mean to, it’s very difficult for a chat to become less secure than you intended.

Applications like WhatsApp, iMessage and Google Messages allow end-to-end encryption but, like we mentioned, it is the combination of security features that make Signal special. The worst messaging option of all is regular SMS text messages — those are sent unencrypted.

If security is on your mind, make sure your phone is also secure. Bad players have ways of hacking phones, but hacking up-to-date phones is difficult.