How to use Signal, the app that lets you send encrypted messages from your smartphone

caption
Signal is Edward Snowden’s messaging app of choice.
source
REUTERS/Charles Platiau

After a nasty year of hacks and leaks, it’s only natural to wonder how you can keep your own digital communication private.

One app promising to do just that is rapidly growing in popularity.

Signal is an encrypted messaging app that lets you send photos or text messages. You can also make secure voice calls over a data network. That means the only people who can see the messages you send are you and the person who receives them.

There’s a lot of work that goes on in the background to make it all possible, but just know Signal is one of the best at keeping everything secure. In fact, Signal says it saw a 400% increase in sign ups in the week after the US presidential election in November.

You can download Signal for iPhone or Android for free. And keep reading to see how the app works. And listen for more about encryption in our lives in the latest episode of our podcast, Codebreaker, from Marketplace and Business Insider.


Signal is one of several encrypted messaging apps for smartphones. But it’s often perceived as one of the best.

source
screenshot

The app is dead simple. Here’s the inbox where incoming messages live.

source
screenshot

You sign up with your cell phone number. The app can automatically detect which of your contacts also use signal.

source
screenshot

Chats look nearly identical to iMessage. You can send text and photos. Everything is encrypted, which means only the sender and recipient can see the message.

source
screenshot

You can also make secure voice calls over a data network. Each person is shown a random pair of words that they can use to verify the call is secure. In this case, you’d tell the person you’re calling “chisel” and they’d reply “sociable” for verification.

source
screenshot

And that’s it! Signal may seem too simple, but that’s by design so all your communication is secure. Creating an account and adding personal info stored on the app’s servers would only increase risk.

source
screenshot

That’s why Edward Snowden says he uses it every day.