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

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.