Signal has been the most high-profile app in the news lately because of the controversy surrounding its use by Defense Secretary Pete Hegseth.
Signal is a secure messaging platform known for end-to-end encryption, often used for private communication.
Concerns about using a commercial messaging app for communicating sensitive military information at the highest levels of government emerged after journalist Jeffrey Goldberg, editor of the Atlantic, was mistakenly added to a Signal group chat. Other members of the chat included U.S. national security officials coordinating airstrikes, just hours before a strike on Iran-backed Houthi rebels in Yemen.
The National Security Council is investigating how Goldberg’s number ended up in the chat. Meanwhile, Hegseth is defending himself against two assertions that he shared classified material on Signal.
Here’s what you need to know about the Signal app:
1. Signal uses encryption
The Signal app, which can be used for direct messaging, group chats and phone and video calls, uses “end-to-end encryption” that prevents any third-party from viewing conversation content or listening in on calls.
It’s the same protocol used by the popular chat service WhatsApp by Meta, according to The Associated Press.
2. Anyone can download it
Though the app is popular with journalists, politicians and organizing groups, anyone can use Signal.
Similar to other messaging apps, Signal can host group chats. But Signal can have group chats with up to 1,000 people.
Signal is free to download in the Apple App Store for iPhone and available for Android devices on the Google Play Store.
There are an estimated 40-70 million monthly users, which is small in comparison to the biggest messaging services — WhatsApp and Facebook Messenger, BBC reported.
3. Security is relative
When using Signal, messages can be set to automatically disappear after a certain time.
But, according to the AP, Signal can be be hacked despite being more secure than normal texting.
Government officials have used Signal for organizational correspondence, such as scheduling sensitive meetings, but in the Biden administration, people who had permission to download it on their White House-issued phones were instructed to use the app sparingly, according to a former national security official who served in the administration, the AP reported.
The official said the app was most commonly used to notify someone that they should check for a classified message sent through other means.
Signal is only as secure as the person who uses it, BBC said. If someone gains access to your phone with Signal open, or if they learn your password, they can see your messages.
4. There are legal concerns
Signal and other similar messaging apps could allow users to skirt open records laws, the AP reported.
Because there’s no special archiving software, messages “frequently aren’t returned under public information requests.”