Nearly everyone’s sent a private photo at some point. But who else is able to see them beyond your conversational partner? When sent over text messages and apps, who else gets a copy? With Signal, a security-minded messaging app, it’s easy to send photos in private.
When sending a photo over text message, the service provider (e.g., Sprint) can usually read the messages. The same applies to messages you send privately over many apps (e.g., Facebook). When you send a message to someone over these platforms, what you’re really doing is sending a message to the service provider. In turn, they’ll relay the message to ensure it gets to the recipient, effectively sitting in the middle of the conversation.
Signal looks and feels like your ordinary text messaging app, but how it protects messages and media in the background is different.
Signal offers end-to-end encryption, meaning that no one except your conversational partner can read the messages — not even the service provider. It’s designed to keep as little user data as possible. You don’t need to take their word for it. Signal is open source, meaning the code is available to anyone. This is especially important because it helps independent specialists ensure it works as intended. In fact, when asked by a court to disclose what data they had on a targeted user, they had almost nothing: a phone number, registration date, and the last login date. These are just a few reasons we recommend it for journalists.
With your most sensitive photos, Signal allows you to set messages to disappear after a short period — anywhere from 5 seconds, to a week. The catch: There’s no such thing as an app that can completely prevent someone from saving a photo. Just like any app, the person who you speak to can still save the photo if they choose, so it’s important that you trust them.
Search for and download it from your preferred app store, or go to signal.org/install from your phone. It only works with other Signal users, so you will need your conversational partner to install it too.
After you launch the app, it will ask you to verify your phone number.
iPhone users: Type in your number and press “Activate This Device.” You’ll receive a six-digit code through a text message. Type in the code and press “Submit Verification Code.”
Android users: Type in your phone number, press “Register” and wait for the app to verify your phone number. When it finishes, it will ask if you want to make Signal your default messaging app, which will allow you to receive traditional text messages and Signal messages within the app. That’s up to you, but it’s important to remember that Signal will not encrypt conversations with anyone using traditional text messages.
Click the pencil icon to select a friend to talk to.
Normally when you take a photo or save an image to your smartphone, it’s saved to your camera roll, making it available to any app with permission to read photos on your phone. In some cases, these apps are tightly integrated in the operating system, such as Google’s Android or Apple’s iOS. Both the Google Photos app on Android and the Photos app on iPhones are designed to allow users to easily back up their photos, which creates a copy in either Google Drive or iCloud. But what if you don’t want those photos to be accessible to any app? What if you don’t want backups?
Signal allows you to take photos within only the app, so the photos never touch the camera roll unless you choose to save them. This also means they won’t be leaked to other services that may read or back up your camera roll, such as Google Drive or iCloud.
Within a conversation, you can send photos by pressing the camera icon at the bottom of the screen. It will feel a lot like your regular camera app, but from here, your photos are not saved to the camera roll.
By default, the person who receives the photo can open the photo as many times as they want. However, when taking a photo, you can optionally prevent it from being viewed more than once. To send a photo that can only be seen once, tap the infinity symbol ( ♾️) in the bottom left corner of the photo editing screen, and hit send.
Let’s say you want to prevent all photos in the conversation from sticking around. We can make messages disappear for both conversational participants automatically, from five seconds after the message has been opened, up to one week.
iPhone users: Click on your partner's name at the top of the screen to open the settings menu for this conversation. Click "Disappearing Messages."
Android users: Click the settings (three-dot) icon in the top right corner. Click "Disappearing Messages."
Move the slider to set the amount of time you'd like to keep the messages, between five seconds to one week.
Maybe you want to keep a photo just for yourself, and no one else. You can send a “note to self” within the app. Once again, just press the pencil icon, and type in your own phone number.
Just like a regular conversation, you can also use disappearing messages to snap temporary photos.
Your conversational partner can still save any photos in the conversation, so it’s important that you trust them with your sensitive photos.
Signal uses your phone number, so just as you need to trust the person you’re talking to, it’s also important that you trust them with your phone number.
It might sound obvious, but end-to-end encryption also can’t protect against anyone with access to your device. That means anyone with physical access to your unlocked phone can see your photos just fine. Consider enabling disappearing messages to minimize risk in case your phone (or your partner’s phone) is ever lost or stolen.
If you connect your Signal number to more than one device (e.g., with both your phone and desktop), your private messages will also appear on each of your connected devices. This includes messages sent in your “notes to self.”
It’s also important to know that encryption won’t help if your device or your partner’s device is compromised with malware. For example: Some kinds of malware are designed to take screenshots or a screen recording and send them to a remote hacker. The single best thing you can do to prevent this is install new software updates for Signal and your device itself. Software updates may include security fixes that help defend against malware. Install them as soon as possible.