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Signal Private Messenger Review

Uncompromising and free end-to-end encrypted messaging for the masses

editors choice horizontal
4.5
Outstanding
By Max Eddy
Updated November 9, 2022

The Bottom Line

Signal Private Messenger is a free messaging service that puts security and privacy first, delivering a polished and safe group, voice, and video chat experience without exploiting its users.

PCMag editors select and review products independently. If you buy through affiliate links, we may earn commissions, which help support our testing.

Pros

  • End-to-end encryption secured with open-source technology
  • Free, nonprofit owned
  • Group, voice, and video chats
  • Multiplatform support

Cons

  • Occasional delays
  • Few fun features

Signal Private Messenger Specs

End-to-End Encryption For All Messages By Default
Requires Phone Number
Supported Client Software Android, iOS, Linux, macOS, Windows
Web Interface
Supports Custom Stickers

This might sound paranoid, but it's unfortunately also true: From cops to advertisers, everyone is out to get your data. Instead of submitting to the surveillance capitalism panopticon, start communicating securely with Signal. This free, cross-platform app protects your messages, calls, and video chats from prying eyes and data-hungry corporations. This app has improved enormously over the years, but it hasn't sacrificed its principles or the security of its users. Among the services we've reviewed, it strikes the best balance between security, accessibility, and fun. It’s an Editors' Choice winner for secure messaging.

Can You Trust Signal?

There are two essential differences between Signal and just about every other chat application out there.

First, it's end-to-end encrypted (E2EE) by default. That means only you and your recipient(s) on Signal can read your messages. Not even the creators of Signal cannot peek inside your conversations. While other services like Facebook Messenger and Telegram include an E2EE option, Signal is one of the very few to make it mandatory. Bear in mind that Signal is built for privacy, not anonymity. In fact, its main concern is ensuring that you're speaking securely with only the people you intend, not hiding your identity. 

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Second, Signal has no incentive to sell your data. It's a 501(c)(3) non-profit organization registered in the US. Companies are keen to grab your data so they can target you for ads or simply sell that information to someone else. That's just not Signal's model. WhatsApp is also free, but it sits atop of Meta's data mining empire. Telegram is still trying to figure out its monetization.

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I am not a cryptographer, but other, smarter people than I have examined Signal. The underlying technology called the Signal Protocol is open-source and has been evaluated by researchers. Its core technology has also been implemented by Meta's and Google's messaging platforms, albeit optionally. While you might not trust those companies, they have vetted Signal's technology and found it worthy. Telegram's encryption scheme is far more controversial. That said, it's disappointing that Signal does not have a bug bounty, which can help incentivize finding potentially dangerous vulnerabilities.

An even stronger endorsement comes, ironically enough, from the FBI. In late 2021, a document emerged outlining what information the agency could legally obtain from various messaging platforms. This confirmed what Signal had long said: It can only provide the date a user signed up for the service and the last time the service was used. This was the least amount of information compared to competitors in the FBI document. Also, because Signal does not back up messages, it is resistant to both legal and malicious attempts to access cloud backups. Apple Messages also use E2EE, but those messages can still be accessed by analyzing backups.

Signal hasn't had smooth sailing when it comes to security. Recently, an attack on a third-party service used by Signal to verify new signups potentially revealed the phone numbers and SMS verification codes of 1,900 users. The company moved quickly to secure its users and disclose the attack—which is what a company should do in this situation.

Send a Signal

Signal is available as an Android app and an iOS app, with companion desktop apps for Linux, macOS, and Windows. Emphasis on companion; you need to register for Signal using a mobile phone. These desktop apps have improved dramatically and can even load a history of your messages when you log in. That process can take some time, however.

Know that Signal does not store or share your phone number, nor does it siphon up your contact lists. Instead, it creates a one-way cryptographic hash of your number and then generates an alert on your device when a friend has joined if the same hashed number appears in your contacts list. 

Screenshot of the macOS Signal app
Signal is primarily a mobile app, but desktop companion apps make it easy to keep the conversation going

The company has been fairly criticized for requiring a phone number, which is a piece of personal information that's not easy to change and prevents anyone without a phone from signing up. Facebook Messenger is one of the few major messaging apps that doesn't require confirming a mobile number. Signal's Accounts feature promises a future where you can sign up without a phone number, but one is still required today. New tools do make it easier to move your Account to a new phone and even to a new phone number.

You're asked to create a PIN when you first sign up. According to Signal's FAQ, this will eventually allow you to "recover your profile, settings, contacts, and who you’ve blocked if you ever lose or switch devices." The company says, this feature is designed in such a way that the information is not accessible, even to the people who develop Signal. You can disable PINs in the Settings.

Screenshots of a photo being marked up, available sticker packs, and a screen explaining the new Payments option
Signal comes with built-in photo markup, sticker packs, and an optional cryptocoin payment feature.

Signal's Payments is an optional, beta feature that lets Signal users send cryptocurrency payments. Although MobileCoin, the crypto used for this feature, claims to be privacy-respecting and carbon-negative, I find the very concept of cryptocurrency repugnant. Fortunately, PCMag does not test Beta features. Hopefully it doesn't distract Signal from its core mission. WhatsApp and Telegram also have payments features, but they use more traditional third-party payment processing.

Chats and Groups on Signal

My testing was done on a Pixel 3a, with some assistance from my colleagues to get insight into other platforms. The Signal app's main page shows a running list of your conversations, with the newest shuffled to the top. You can pin up to four conversations to the top of your screen for easy access. Use the search bar at the top of the screen to query words used in your conversations or people from your contact list. A Settings panel lets you control the app's appearance, how it stores data, and other essential features. It's also where you go to link your Signal account to a desktop companion app.

Images showing an image of a cat and a Red Panda, and conversations showing the disappearing messages feature
Attachments can have view limits, and chats can have self-destruct timers. You can also attach audio for quick messages.

When inside a chat, you'll be in familiar territory. If you've used a chat app in the last decade, the features and layout will be familiar to you. Handy buttons on the text field let you attach files, add privacy-respecting stickers, take and edit selfies, and record up to 5 minutes of encrypted audio. The Disappearing Messages option (found in the three-dot menu) lets you set a lifespan for your messages. That means your messages are automatically deleted, even from the recipient's phone.

When you send pictures, you can choose to allow the image to be viewed indefinitely or just once by tapping the infinity symbol in the bottom left of the screen. As a proponent of safe sexting, I think this is a great feature. Be aware that even disappearing messages and pics can be captured with screenshots, or by taking a photo of the screen.

Groups work much the same as messages. Select a few contacts, or skip that and simply create an empty group, and then add a name and a picture. That's it! Groups are encrypted but messages to groups with non-Signal users will not be encrypted and will only use SMS.

You can add people manually from your contacts or you can create a sharable link or QR code to quickly populate your new group. Newly created groups now have admins (the creator of the group by default) who can change group settings, assign other admins, approve members joining from a link, and, of course, remove other members as well.

For years, Signal has also supported SMS messages on Android and you could opt to use Signal as your primary messaging application, usurping the built-in SMS messaging app. This let you communicate with non-Signal users via un-encrypted SMS, all from within the same app. While Signal did an admirable job sign-posting when a message was secure or regular SMS, the company announced in October 2022 that it was dropping SMS support in the coming months.

While I'm sad to see the end of this unique feature, it never worked perfectly and was only available on Android. Besides, other messaging apps never opted to include SMS, so dropping support brings Signal more in line with apps other people are already familiar with.

Signal by Voice and Video

Secure voice calls have been a feature of Signal since its earliest incarnation as RedPhone/TextSecure. Tap the phone or camera icon at the top of a chat to start a secure voice or video call. You switch your camera on to turn a voice call into a video chat. 

Group chats also support video calls with up to 40 participants, which is large enough for a friendly chat or a small group but can't hold a candle to Zoom. Telegram allows up to 1,000 viewers for broadcasts, but only the first 30 can share their video. Like Discord, video calls in Signal persist until everyone has left, but nonparticipants can continue using the text chat. Voice calls aren't explicitly supported for groups, but you can just turn off your camera. The effect is the same. Note that video calls and group chats work across every platform Signal supports.

Screenshots of a three-person video call on three differnet devices
A three-person video call as it appears on (from left to right) iPhone, macOS, and Android

In testing, I found the video chat feature straightforward and easy to use. In just a few minutes, we had iPhone, Mac, and Android users chatting happily. The video quality varied wildly between users. One participant, on the west coast, appeared surprisingly grainy while another participant calling from overseas looked crystal clear. In the past, I've had issues with Signal calls being unreliable and have avoided it, but perhaps I should reconsider that position.

I'm sad to see that Signal no longer displays two-word code phrases that you and your recipient could say to each other to confirm identities. It was always overkill and no doubt confusing, but I miss its spy-vs-spy-ness.

What Are the Challenges and Drawbacks of Signal?

If you're familiar with WhatsApp or Apple Messages, some of Signal’s quirks might confuse you. For one thing, you won't be able to see the previous chat history when you join a group. That's because those messages can only be read by their intended recipients, which, at the time, didn't include you. 

You'll also periodically see warnings that a contact's Safety Number has changed. This means that something has occurred that required Signal to generate a new cryptographic key for your conversation. This alert could mean your messages are being intercepted in an attacker-in-the-middle scenario, or it could mean your friend got a new phone. These messages appear far less frequently than they used to, but they are always confusing. You can tap on a user's icon to view and confirm their safety number, but no one actually does this.

Screenshots showing conversations with Safety Number warning, a contact page, and a page where you can confirm someone's Safety Number
Signal's Safety Number system may be confusing, but it lets you know when someone could potentially be intercepting your messages. However, it's almost always because your contact reinstalled the app.

In my experience, Signal is extremely reliable, but the times when it fails are frustrating. Anecdotally, it seems like Signal on iPhone doesn't reliably generate notifications, in one such example.

Some of this stems from Signal's adoption issue, which is endemic to all secure messengers. People understandably aren't interested in installing yet another app for messaging if most of their friends and family aren't there. Signal is more popular than ever, but I've noticed that while many people sign up, few stick with it and many simply uninstall the app. Apple Messages avoids this issue by virtue of being default, while WhatsApp and Telegram have built solid overseas user bases.

Also frustrating is Signal's small collection of frivolous but fun features found in competitors. True, it supports stickers, but these are hard to find and install because Signal doesn't have a centralized sticker and app store like Apple and others. Telegram, in particular, has made sticker creation and sharing very simple, giving its users far more options to express themselves. Signal also can't boast anything like Memoji digital masks, effects, or even Zoom's virtual backgrounds. The recently debuted Instagram Stories-esque feature might help bring some zing to the app. We're looking forward to testing it in the future.

The Best of Both Worlds

Security and ease of use are often on opposite ends of the spectrum, but Signal has managed to deliver a happy medium for years. It has experienced continual improvement and only become more fun, more polished, and more popular over time all without compromising its core promise of secure, private communication. 

Despite being more fun to use than before, it seems unlikely to ever match less secure competitors for fad features. But the biggest drawback to Signal remains its relative niche audience. People clearly understand the value of a privacy-focused service like Signal, and the years of usability improvements seem to have drawn people in. But not everyone seems to stay, and remain tied to more popular, but less secure, services. If you're sick of feeling like all big tech companies do is betray your trust, you owe it to yourself to try Signal.

Signal Private Messenger
4.5
Editors' Choice
Pros
  • End-to-end encryption secured with open-source technology
  • Free, nonprofit owned
  • Group, voice, and video chats
  • Multiplatform support
View More
Cons
  • Occasional delays
  • Few fun features
The Bottom Line

Signal Private Messenger is a free messaging service that puts security and privacy first, delivering a polished and safe group, voice, and video chat experience without exploiting its users.

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About Max Eddy

Lead Security Analyst

Since my start in 2008, I've covered a wide variety of topics from space missions to fax service reviews. At PCMag, much of my work has been focused on security and privacy services, as well as a video game or two. I also write the occasional security columns, focused on making information security practical for normal people. I helped organize the Ziff Davis Creators Guild union and currently serve as its Unit Chair.

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