Signal & Privacy

Edward Snowden once said he uses Signal every day, shining a spotlight on a messenger that was previously little known to the general public: Signal. Ever since WhatsApp announced drastic and widely debated changes to its privacy policy, and Elon Musk began advocating for Signal, the messaging service has seen an unexpected surge in popularity. All the more reason to examine whether Signal is a secure messenger and a viable alternative to WhatsApp.

Instant Messengers & Data Privacy

There are many messenger apps out there, but currently, more than two billion people around the world are concentrated on the most well-known messenger: WhatsApp . However, this service was sold to Facebook in 2014 for a double-digit billion-dollar sum, and since then, things have looked rather difficult when it comes to WhatsApp and data privacy, as every use feeds the tech giant Facebook with at least your metadata (such as device type, usage duration, etc.).

Now comes a new privacy policy update, which is intended to tie WhatsApp even more closely to its parent company, Facebook, shaking up many users once again—and this time, it seems, for good. Users are flocking to alternative messaging services in droves. The prospect of feeding the Facebook data octopus with every use of WhatsApp apparently no longer leaves people as indifferent as it once did.

But other instant messengers also face issues beyond just data security and privacy that land them in the headlines. Telegram , for example, has gained a reputation for being a haven for right-wing extremists, conspiracy theorists, and other unsavory characters due to its lack of content moderation in its numerous groups.

Other privacy-friendly services that were just gaining traction are simply going offline for good, leaving behind confusion and undelivered messages—as happened with Hoccer.

Now, in Signal, it seems a privacy-secure messenger alternative has been found that also holds up from a GDPR perspective. Or does it?

Is Signal more secure than WhatsApp?

Many people looking to leave WhatsApp are now comparing it to the Signal app, as it is considered one of the most secure instant messengers. But is Signal really more secure and a good alternative to WhatsApp? Taking a closer look, Signal actually has many more advantages in terms of data privacy than the market leader, such as:

• End-to-end encryption: Even the operators have no access to the content of the messages. This is also the case with WhatsApp (WA). The market leader, WA, does not possess any of the following features.
• Long-term encryption: Perfect Forward Secrecy ensures that it is impossible to decrypt older messages if a supposedly secret personal user key is compromised. Based on end-to-end encryption, temporary keys are created for each message and deleted once the message has been delivered.
• Encrypted user profiles: Only authorized contacts of a Signal user can see and access their user profile. This also prevents access by the operators.
• Address book: Signal users' address book contacts are not uploaded to the operating servers.
• PIN: Personal information on Signal is secured and protected with a personal PIN.
• Call encryption: Just like with messages, this is handled via the Signal protocol.
• Tracking: Signal explicitly does not use any tracking technologies. This means that your metadata (such as device information or the type and frequency of usage) is not analyzed by Signal.

Most of the other features will be familiar to WhatsApp users. You need a mobile number to register, and then you have access to features such a

• individual and group chats,
• mentions in group chats,
• desktop use,
• sticker use,
• voice and video calls, and
• voice messages, and much more.

The only thing not (yet) available is a status option. However, the "view once media" feature allows you to send images, messages, and the like that can only be viewed once. After that, they delete themselves automatically. And speaking of deleting: in the latest version, sent messages can be deleted within three hours, even in group chats.

Signal includes additional security measures that, like the source code, can be inspected. Signal's source code is open source and available on GitHub , which means anyone can review it and check it for security.

By the way: Android users can use Signal to send and receive SMS.

Signal & GDPR: How secure is communication with the instant messenger Signal?

Signal operates according to one of the core principles of the GDPR: data minimization. The so-called zero-knowledge principle ensures that even the operators have no access to user data. So, is Signal preferable to WhatsApp? From a data protection perspective, absolutely. And now is the perfect time to convince your skeptical friends to make the switch, too.