Messenger
Signal and data protection
Signal is run by the non-profit Signal Foundation in the USA and funded by donations. The Signal Protocol is regarded as the benchmark for secure encryption – WhatsApp uses it too.
In brief
- Everything end-to-end encrypted: one-to-one and group chats, calls, files and profile data.
- Very little metadata: according to Signal, it essentially stores only when an account was created and when it last connected.
- Open source and free, with no advertising.
- Phone number: a phone number is required for normal registration. Since 2024 you can hide it and use a username instead. Since autumn 2026, Signal has been testing paid registration without any phone number at all in a beta version for Android.
What you should bear in mind
- The provider is based in the USA. However, because Signal stores hardly any data, it can hardly hand any over.
- If you have not set up a backup, your chats will be lost when you change device.
How to set up Signal in a privacy-friendly way
The labels may differ slightly depending on the app version.
- Hide your phone number: Settings → Privacy → Phone number → set “Who can see my number?” to “Nobody” and “Who can find me by my number?” to “Nobody”.
- Set up a username: tap your profile → Username. Share the username or the QR code instead of your number.
- Turn on Registration Lock: Settings → Account → Registration Lock. This stops anyone from taking over your account with your number.
- Disappearing messages: Settings → Privacy → set a default timer for new chats.
- Screen lock: Settings → Privacy → Screen lock.
- Check safety numbers: compare the safety number with your important contacts.
Further reading
Sources
- Signal: Privacy policy
- Signal Support: Phone number privacy and usernames
- Privacy Guides: Signal enables phone-number-less registration in beta (16.09.2026)