Signal Messenger App: What It Is

What to know about the secure messaging app

Signal is a secure, encrypted messaging app that's available for free for iOS and Android devices, and there's a desktop app, too.

What Is Signal Messenger?

The first thing to know about Signal is that it's similar in function to WhatsApp. That's because Brian Acton, who founded WhatsApp, was a co-founder of the Signal app. The two apps also use an open-source encryption protocol that Acton developed, but that's about where the similarities end.

Signal is a free, secure messaging app that lets you send messages, images, and files, have phone conversations and chat individually or in groups in a secure way that's nearly untraceable. That's because Signal uses end-to-end encryption and uses only your phone number as an identifier. Signal says they collect as little data about you as possible.

For example, when a federal grand jury subpoenaed Signal to provide data about two users in 2016, the only data Signal could provide was the account creation date and the last connection date. Signal does not collect any of the data other messaging apps and services collect: no messages, groups, contacts, profile information, or anything else. No collected data means nothing to share with others.

For you, this means that Signal also doesn't have access to any messages or data that you share. The only people that see that data are you and whomever you're messaging.

What Else Sets Signal Messaging Apart?

While the Signal app's security is the driving factor that pushes people to download and use it, there's something else that sets Signal apart from other messaging apps and paves the way for the secure, private messaging system it is. Signal is an independent, non-profit organization.

Being a non-profit means that Signal isn't ad-supported, so the company has no incentive to sell your data. Donations from users support them, so you never have to deal with ads, trackers, or other interruptions that are not only annoying but can also put your privacy at risk.

Digging In to Signal Encryption

Signal has a proprietary encryption protocol that protects messages from end-to-end. From the time you create it until it is delivered, read, and deleted, the recipient, the message, and any attachments remain encrypted.

Think of it this way, when you create a message using the Signal app, the data is scrambled up into an unrecognizable form. The only way to unscramble it is with a private encryption key, which only the message's recipient has. Much like a physical key that works in a door lock, that key is specific to the recipient. Unlike a physical key, however, it works only with one lock.

No one else, not even Signal, can see or collect data about the information that's in the message you're sending. And suppose you're concerned about someone else seeing the message on the recipient's device. In that case, Signal even offers a self-destructing message type, which will destroy any message you send after a specified amount of time.

Finally, everything in the Signal app is stored locally on your device. Nothing goes into the cloud. Nothing goes onto Signal's servers. The only way your messages can be compromised on Signal is if your device is compromised.

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