Activating end-to-end encryption for calls and messages might seem a little extreme for private citizens. But with digital liberty under attack, tech companies cooperating with spy agencies, and cyber attacks big and small affecting thousands every day, it behooves everyone to take privacy seriously.
Signal, a secure app from Open Whisper Systems, is endorsed by no less a privacy advocate than Edward Snowden. It's a blend of the encrypted RedPhone VoIP app and TextSecure SMS app, both from Whisper Systems, which was bought and dismantled by Twitter in 2011. Whisper Systems co-founder Moxie Marlinspike then built Open Whisper Systems using software from his former company that fell under free software licenses after the Twitter acquisition went through.
The Signal app, available on iOS and Android, can send messages and make calls when both parties are connected to the internet. Though it has had some competition from WhatsApp and Telegram, its reputation for security has made it indispensable to many, particularly those who live under governments that censor and monitor citizens (not to mention those who use it and other chat apps for more nefarious purposes).
In December, for example, Signal for Android was updated to bypass censors in places where the app has been banned by deploying domain fronting, which uses one domain on the outside of an HTTPS request and another within.
Regardless of whether you need such robust privacy features, using a secure app is a smart choice. Here are some ways to make it work for you.
Signal now lets you make secure video calls. To use it, place a call by going to the contact's name and tapping the phone icon, then when the call is being placed, tap the video icon.
Making a voice call with Signal is simple. The only additional step you're going to notice is that you have to verify that the call is secure. This is done by each party being sent the same pair of words that they can verify with the other party by reading them aloud once they're on the call. To place a call, tap the name of the person you want to call and then tap the phone icon. The phone will ring and the words will appear at the bottom of the screen.
3There's Safety in Numbers
If you want to verify that you have secure communication with a contact, you can verify safety numbers with them either in person or through messages. Whichever you chose, you should both open Signal and tap the other's name in Conversations. Then select Verify Safety Numbers. This will bring up a QR code and strings of numbers. If you are physically with the other person, you can hover your phone over theirs and select Scan Code at the bottom of the screen. If you want to verify over a message, tap and hold the number strings and then select Compare With Clipboard.
But what if your safety number changes after getting a new phone or re-installing Signal? Don't worry, Signal verifies safety numbers inside a message. When a message comes in from a user you've communicated with but who has a new safety message, you'll see the notification within the message screen but you can still proceed with the conversation. Tap the message that says "Safety number changed. Tap to verify." Then you can either accept the new safety number in a pop-up right there or click Accept New Safety Number and be led through the manual process again.
Since Signal is secure, clearing your history isn't a necessity, but if you like the neatness of no messages, want a clean start, or are worried about your phone in someone else's hands, go to the settings wheel, tap, Privacy, and then select Clear History Log.
If that's too arduous a process, you can set your messages to self destruct. Go to the conversation, tap the menu, and select Disappearing Messages. Select a delete time between five seconds to one week. Once enabled in a conversation, you'll see an hourglass under each message.
6Stop the Broadcast
By default in Signal, your device's notification screen will display a contact's name and message when they message you. But you can turn this off.
On Android go to Device > Sound & Notification > When Device is Locked, and choose between the options to Show All Notification Content (name and message appear), Hide Sensitive Notification Content (just says that there is a message), and Don't Show Notifications at All. can turn this off.
For iOS, go to Settings > Notifications > Background Notifications > Show to select between Sender Name & Message, Sender Name Only, or No Name or Message (will display only that there is a Signal message).
7From the Desk of
Though you need an Android or iOS device to register to use Signal, you can use the app on the Chrome desktop browser once you sign up. Go the Chrome Web Store, download the Signal app, and open it. Click Get Started and confirm you have Signal installed. A QR code will pop up on your computer screen. Open Signal on your phone, go to Settings, then Link New Device, scan the QR code with the phone, and name the desktop client.
It's a serious platform, but not too serious, as this addition to Signal proves. The Android version of the app recently got stickers, the ability to send doodles, and integrated GIFs. Don't scoff; a number of people said they wouldn't switch from Signal unless it had stickers. When you go to message a contact, tap the large blue button next to the message area and select from GIFs and stickers. Open Whisper Systems says it plans to integrate these features into the iOS version. One word of caution: when searching for a GIF, the terms are hidden from Signal and the IP address of your device is hidden from Giphy, but there are still ways to narrow down where the request came from.
9Just Your Type
You can send file types of all kind securely with Signal. Open a chat, click the paperclip next to the text area and you can take and send a photo, send a photo from your photo library, and send a document. If you choose to send a document, you can choose a doc, text, PDF, or any other type of file from iCloud Drive, Google Drive, or Dropbox, or you can just copy and paste it right into the text field.
If you're in a group chat but you just don't want to hear it right now, you can mute notifications. Go to the group chat and click on the name, scroll down, and tap Mute.
If you have an Android device, you can set up a passphrase to get into Signal. Go to the menu, select Settings, then Privacy. To enable a passphrase, set the slider to Enable and choose a passphrase.
12This Is a Private Number
For all the ways it addresses privacy, Signal does not give you a way to mask your phone number, oddly. There is no simple solution, but there are things you can do.
As the The Intercept outlines, you can register using a number from a service such as Google Voice or Skype and tie that number to a dedicated device. That second part is easy for Android users because you can set up a second account on your phone. If you have an iPhone, you'll have to either use another iOS device (like an iPad or an iPod touch) or Android device, but that gadget does not need a cellular connection or SIM card.
On the additional device or from the alternate account, install Signal, open it, and type in the phone number you wish to use. You will get a message that authentication failed. Choose voice verification by tapping Call Me. The number you entered will ring and you will hear a voice that will give you a six-digit number. Type that number into the verification box in the Signal app and then select Verify.
This is a messy process, but if keeping your private number private is important to you, it could be worth it.