Signal for Windows download

Overview: what this messenger is and who created it

Signal Private Messenger is a free, open-source chat app maintained by the Signal Foundation, a nonprofit co-founded by Brian Acton (one of WhatsApp’s original founders) and cryptographer Moxie Marlinspike. Interest in Signal rose sharply when WhatsApp updated its data-sharing policies with Facebook, prompting privacy-conscious users to switch to an app that emphasizes minimal data collection and robust encryption.

How Signal secures your communications

Signal uses end-to-end encryption for messages and calls, which means only the sender and recipient can decrypt content. Because of that encryption and the app’s limited data retention policies, service providers and most external parties cannot read your conversations. These properties make Signal a popular choice among journalists, public officials, and anyone who wants to reduce the risk of third-party access to their messages.

Signal’s code is publicly available, which allows independent security researchers to review and suggest improvements. The foundation argues that this transparency makes the app more secure over time by exposing bugs and vulnerabilities to trusted reviewers.

Core features and how to use them

Open-source codebase that can be audited by outside security experts.
End-to-end encryption for both messages and voice/video calls.
Disappearing messages (timed self-destruct) to remove chat history automatically.
Local app lock using a PIN or biometric (fingerprint/face) to prevent access on a shared device.
Optional registration protection (two-factor/registration lock) to prevent account hijacking.
Group chats with capacity for multiple participants and administrative controls.
Multiple invitation methods (link, SMS, or social media) to bring contacts onto the platform.
Contact syncing to discover which of your contacts already use the app.
Ability to sign up with alternative numbers (for example, a Google Voice number) to keep your primary number private.
Options to disable cloud backups or prevent call/text sync with services such as iCloud.

Practical privacy suggestions

Enable the app’s registration lock or two-step verification to add an extra authentication layer.
Turn off any automatic cloud backups or platform-level sync if you don’t want message metadata stored on third-party services.
Use a secondary phone number (like a VoIP number) when you prefer not to reveal your primary number.
Verify safety codes with frequent contacts for added assurance the encryption keys haven’t changed.
Lock the app behind a passcode or biometric so physical access to your device won’t expose conversations.

When Signal is (and isn’t) the best choice

Signal is a strong option if you prioritize confidentiality and minimal data retention over cosmetic extras. It deliberately keeps a lean feature set focused on secure messaging rather than offering extensive sticker packs, themes, or large ecosystem integrations.

Other messaging apps (for example, Telegram, WeChat, and platform-native messaging apps) may provide some overlapping privacy features and additional conveniences. If your contacts do not use Signal, messages to them will fall back to other networks or require an invitation—both of which can limit seamless adoption. For users handling sensitive material or seeking a communications tool with strong cryptographic protections, Signal remains a widely recommended alternative.