Signal, an Alternative to WhatsApp and Messenger

WhatsApp and most messaging apps are funded by advertising, so they collect your private data to sell it. Privacy-friendly alternatives do exist, such as Signal.

Privacy

Signal is often cited as one of the most privacy-focused messaging apps. It has notably been recommended by whistleblower Edward Snowden as a way to protect against mass surveillance programs, such as those he exposed in the United States.

The Signal app and the cryptographic protocol it uses are released under free (libre) licenses, meaning their source code is publicly available. This transparency builds trust: it allows the community to audit them and detect any potential vulnerabilities. Signal uses end-to-end encryption¹ for all conversations—messages, group chats, file sharing, voice calls, and video calls—ensuring that only the intended recipients can read the messages.

No Ads

Unlike WhatsApp or Messenger, which are owned by Meta (Facebook) and collect personal data for commercial purposes, Signal minimizes data collection. Signal requires only a phone number to create an account, stores virtually no additional information, and does not create public profiles. Your conversations remain private; they are not used for targeted advertising, and your chats are not cluttered with ads based on your online behavior.

Financial Independence

The app is supported by a non-profit foundation and funded by donations. This funding model provides an additional safeguard for your privacy: the service is not subject to advertising pressures or incentives to monetize your data.

Why Use Signal Instead of Matrix?

Signal is very easy to use. Just install it from the app store, and it’s immediately “ready to use,” with encryption automatically enabled everywhere.

This simplicity comes with drawbacks. Signal requires users to provide their phone number and use a proprietary² operating system, either Android or iOS³. Furthermore, the Signal protocol is centralized: all communications pass through a single official server managed by the Signal Foundation. Even though Signal minimizes metadata, the server knows when two users are online or when they are exchanging messages. However, the server cannot read the content thanks to end-to-end encryption, and messages remain encrypted even after the account is deleted. The risk therefore seems limited: even if the server were hacked, the content would remain encrypted. The server also has no access to contacts, which are stored locally on devices. Note that Signal’s server source code is also publicly available, ensuring the same transparency and the ability to verify its operation.

Signal also offers an app for Windows, macOS, and Linux, but only as a supplement to the mobile version. You must therefore always have access to an Android or iOS device to create an account and, if necessary, to verify the account’s authenticity. That’s a shame.

For those who prefer free (libre)⁴ systems and don’t use Android or iOS, Matrix is the solution for you. You don’t need to provide a phone number to use Matrix, and its protocol is decentralized. You aren’t tied to a single server and can even manage your own Matrix server. Self-hosting, however, requires active server management to ensure encryption, limit metadata exposure and retention, apply security patches, and more. A poorly configured server can expose far more metadata and present greater vulnerabilities. Creating an account on the official matrix.org server offers the same simplicity as Signal, without needing to provide a phone number and without relying on Android or iOS.

Conclusion

Signal is a solid benchmark for privacy and communication security. Ease of use, free software, a robust encryption protocol, and a minimal data collection policy make it a wise choice for anyone who wants to protect their communications. However, the requirement to use Android or iOS and its centralized approach (single official server) may lead some to prefer Matrix. If in doubt, try both!