When I heard there was an app that encrypts messages between smartphones, I had to investigate. And boy did I get WAY more than I expected.

Signal is a free messaging application for mobile devices and desktops that secures conversations by encrypting communication between devices. It features an interface similar to that of other messaging apps such as WhatsApp and Telegram. Signal users can set a lock passphrase and secure access to the app at will. Thanks to this feature, messages and conversations remain safe in the event of a lost device.

Signing up is simple. Signal only asks users to provide a mobile phone number for authentication purposes. The developers do not store any conversation data or personal information on their servers. Just the phone number used to authenticate the account. Users can unregister anytime. Upon re-registration, user app settings, such as the color theme, passphrase, conversations, etc. are restored in an instant. This could be useful when removing conversation info from a device before disposing of it.

Signal initiates a passphrase lock when the app is closed or forced to quit. I would suggest force quitting each time you are finished using the app to be certain your conversations are safe. Each conversation is verified with a unique safety number to ensure users cannot be spoofed. Users can verify each other’s safety number in real life and confirm that they are the intended recipient of messages.

I tested Signal for about a week after hearing it was recommended by infamous security expert Edward Snowden for secure communication. The first thing I searched for was the option for a dark theme. Sure enough, Signal features a dark theme setting. (Dark interfaces make me feel even sneakier using Signal).

I would be remiss if I didn’t bring up the VoIP features of Signal. Video AND Voice calls over mobile data and WiFi. I’m proud to say the call quality sounds crisp and even clearer than regular calls started via the dialer app. It’s like the other person is speaking right in front of you. It is unclear why the quality is so clear, but it’s better than any other VoIP service I’ve ever used. The Bluetooth subsystem may cause slight latency in calls while in use. I noticed some lag in the connection when a friend connected a Bluetooth headset mid conversation. However, this is not uncommon with mobile devices.

For technical support, the help option redirects to the support section of the Signal website. The Support section features a great FAQ section for each platform running Signal. It seems they carefully selected the most important FAQs to display. There is also a search function for greater troubleshooting.

In conversations, I noticed Signal censors thumbnails on my video transfers. Other apps display an image from the video and some even allow users to select a specific frame for display. My guess is this has been removed for security against shoulder surfing.

Signal is a solid messaging app. The only thing I didn’t like was the Inactivity Timeout for auto-locking when idle for a set amount of time. It doesn’t seem to work at this time (tested with 2 minute settings and it did not time out). To optimize Signal, the developers should also consider altering Input validation settings. It should limit the maximum number of incorrect inputs before initiating some action. Maybe text the user, wipe all conversations, something like that. Allowing users to select their own action in response to invalid inputs would be a great addition.

When the app closes, a notification appears informing the user the app is in use and unlocked. I believe the auto lock feature should be adjusted to instantly lock on closing the app in addition to force quits. Again, allowing users to alter this setting would be a great addition.

I have recommended this app to friends and family who are serious about securing their conversations and messaging on their devices. Definitely download it and give it a shot. I’m hoping my contacts will all download Signal so I can make a full transition to secure communication.