More and more people communicate via messaging apps, as phone calls are seen as old-fashioned, and email can be too complicated. Messaging has the advantage of being more conversational than email, and more immediate.
Unlike in the early days of messaging, such as SMS and AIM, many of today’s messaging apps are secure, with end-to-end encryption protecting your conversations. Messaging apps can be a great way to send sensitive information to others, even to send passwords or other user credentials.
Here are five secure messaging apps you can use, on Mac, iPhone, and iPad, as well as on other platforms.
Compatibility: macOS, iOS, iPadOS, watchOS
Offered by Apple, iMessage has been available on iOS since 2011, macOS since 2012, and watchOS since 2015. It is by far the most convenient way to securely send messages for users of Apple devices. Using end-to-end encryption by default, it is very secure. Only you and the person you’re messaging can get to the contents of an iMessage conversation. More on iMessage security can be found in this Apple Platform Security document.
For Apple device users, setting up and using iMessage is very easy. Sign into your device with your Apple ID, or create a new one, and you’re good to go. There aren’t many settings you can adjust. You can choose which phone numbers and email addresses people can use to contact you. And you can enable or disable read receipts. On iOS, you can also set a low quality image mode, and you can enable text message forwarding, so SMS messages sent to your iPhone can be forwarded to your other devices. There are a few other settings for iOS and iPadOS, and if you have an Apple Watch, you can choose whether dictated messages are sent as text or audio, and set some default replies that you can tap on the screen of your watch.
There are a couple of important caveats that may convince you to use an alternative platform, however.
While the platform is called iMessage, the Apple app is called Messages. It’s important to understand that you can send both iMessage (secure) and SMS (insecure) via the Messages app. You’ll know you’re about to send an iMessage if the round “send” arrow button is blue, and you’ll notice that your messages will have a “blue bubble” as well. (If your “send” arrow button is green or your outgoing messages appear in a “green bubble,” this means your recipient is not using iMessage. That means your texts will be sent insecurely via the antiquated SMS system. This most likely means that the recipient has an Android or other non-Apple phone, and cannot use iMessage.)
You can choose whether or not to enable Messages in iCloud, so your iMessages can be recovered in case you lose all your trusted devices. (To find this setting, search your iOS Settings app for the word “Backup,” tap on it, and then look for “Messages” in the “Apps Using iCloud” list.) Note that if this setting is enabled, your decryption key is stored on Apple servers, which is less secure. You have no way of knowing whether the person you’re messaging has this setting enabled or not. If that concerns you, then you may wish to choose another app below for .
Compatibility: macOS, iOS, iPadOS, Android, Windows, Linux
Signal is most well known for its endorsement by Edward Snowden, who says, “I use Signal every day.” Signal uses end-to-end encryption to keep your communications private and secure, including private messaging and private calling, and the Signal protocol is becoming a standard in messaging services (WhatsApp, notably, has adopted the Signal protocol).
The setup and use of Signal is very straightforward. Even if you only end up using the iOS version of Signal, its security alone might make it worth it for you. You can sync Signal messages across devices, on an iPhone, iPad, or Mac, as well as Windows devices.
Compatibility: macOS, iOS, iPadOS, watchOS, Android, Windows, Linux, Web
Telegram is very easy to use, and it’s available on more platforms than any other app on this list. It offers plenty of settings to set it up how you like it. Two-step verification, password protection for the client, and various settings to customize the look and feel of the chat are a few examples why Telegram is a great messaging app option.
It’s very important to note that chat encryption is not enabled by default, so if you use Telegram, make sure to initiate “Secret Chats” with your friends. The encryption that is used, once enabled, is based on the MTProto 2.0 mobile protocol. Telegram has been broadly criticized for a number of reasons. Thus, although Telegram is well known and available on many platforms, it may be worth looking into other alternatives before deciding whether to use it.
Compatibility: macOS, iPhone, Android, Windows, KaiOS, Web
WhatsApp, which was acquired by Facebook in 2014, started offering end-to-end encryption in mid-2016 and uses the Signal protocol. In spite of its ownership by Facebook—a company for which privacy is not a key feature—WhatsApp can be considered a secure messaging app. Your communications are encrypted, so only you and the recipient can see them.
While WhatsApp is not widely used in the United States or Europe, it is the predominant mobile platform for communication, commerce, and more in India, where it may reach 500 million users soon.
While WhatsApp is available for macOS, the Mac version is not really a stand-alone app. Your phone must be on the same Wi-Fi network, and the macOS version will not work if your phone is not available.
Additionally, when it comes to iOS support, WhatsApp is only supported on iPhone. It is not supported on iPad or iPod touch (however, WhatsApp offers a Web app that can be used in a browser).
Cost: $2.99 one-off app purchase
Compatibility: iOS, iPadOS, Android, Web
Threema is an anonymous encrypted messaging platform. Threema does not link your account to your phone’s SIM card, but to a Threema ID which is generated when you sign up. You can use Threema with an iPhone, iPad, or a limited web version.
One unique advantage of Threema compared to the others on this list is that you can create an account anonymously, and without having to provide a mobile phone number. This gives Threema some additional niche use cases; for example, a parent can use it to securely message with a child who only has a Wi-Fi capable device like an iPod touch, iPad, or Android tablet.
But there’s another way in which Threema is unlike the other apps listed above: you have to pay for it. A one-time purchase of the Threema app ($2.99) gives you access to the service. Because of this, fewer people use Threema. But if you have a small group that wants secure, anonymous messaging, Threema might be for you. The company also offers plans for businesses and organizations.
There are a few other secure messaging services, but many of them present issues, such as the reliability of their encryption, how they handle user data, and their owners. Here’s an independent comparison of a number of apps and their features. (Note that, of the apps we’ve listed above, that’s site author only recommends Signal and Threema. You can read the details and make your own decision.)
Messaging and email offer different advantages and disadvantages. You may also want to use secure email, and you can read our examination of three free secure email services that protect your data and privacy.
In addition to using a secure messaging app, you should use an anti-virus and two-way firewall solution on your Mac to make sure malware and key loggers can’t monitor your chats. Furthermore, in the event your Mac is lost or stolen, the use of disk encryption and a strong login password can prevent access to your communications and other data. On iOS, use a 6-digit passcode and TouchID. (Apple’s iOS uses full storage encryption by default.) Additionally, you may want to use a VPN if the network or service provider are not trusted.
Using messaging, or any form of online communications, is not as worry-free as it once was. However, given the improvements in security, there is much to be said for these apps. By using secure, encrypted messaging apps, you can carry on communicating with friends, family, and colleagues, knowing that your conversations remain private.
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