Signal: when to install it, and when not to
Messaging where end-to-end encryption is the default for everything rather than an option buried in a menu. The protocol is published, so the trust claim…
The short version
Signal: The benchmark for private messaging, run by a non-profit and audited repeatedly. Everything is end-to-end encrypted including calls, and the desktop app links to your phone rather than existing on its own.
| Licence / price | Free · Open source |
|---|---|
| Platforms | Windows, macOS, Linux, Android, iOS |
| Category | Communication — 6 programs |
| Official download | https://signal.org/download/ ↗ |
What it is for
Messaging where end-to-end encryption is the default for everything rather than an option buried in a menu. The protocol is published, so the trust claim is checkable.
When to pick something else
It only helps if the people you talk to are there too, and it is not a replacement for a team chat with channels and history. Network effect, not features, is the real limitation.
What independent reviewers found
We do not run lab tests or benchmarks. These summaries are written in our own words, with the publisher named and the original linked. Our citation policy explains what we will and will not reproduce.
Cohn-Gordon, Cremers, Dowling, Garratt, Stebila (IACR ePrint / IEEE EuroS&P) — 2016, revised 2019
What the source says. A formal analysis of the Signal protocol's key agreement and Double Ratchet, published at IEEE EuroS&P 2017, proved security properties for its core and reported no major design flaws, while noting that a predictable random number generator would create a weakness.
What we take from it. This is the strongest evidence on this list, and it still has boundaries: it is about the protocol's design, not about every device, backup setting or contact verification habit.
A Formal Security Analysis of the Signal Messaging Protocol ↗ (Cohn-Gordon, Cremers, Dowling, Garratt, Stebila (IACR ePrint / IEEE EuroS&P) · 2016, revised 2019 · Academic cryptanalysis)
How it compares in Communication
These are the alternatives we would consider for the same job. The notes are the same ones used on the main list, so there is no separate ranking hiding on this page.
| Program | Licence / price | Platforms | Why it is on the list |
|---|---|---|---|
| Element Publisher's site ↗ | Free · Open source | Windows, macOS, Linux, Android, iOS | A client for the open Matrix network, which means you can self-host or join someone else's server and still talk to people on other servers. Choose it for sovereignty, not for polish. |
| Telegram Desktop Publisher's site ↗ | Free · Closed source | Windows, macOS, Linux, Android, iOS | Fast, syncs across devices without needing your phone nearby, and handles very large files. Only private chats are end-to-end encrypted, so treat groups and channels as server-visible. |
Practical notes
- Set a registration lock and a PIN so an account cannot be re-registered on another device easily.
- Check linked devices occasionally and remove any you no longer use.
Questions people ask
Is a lock icon the same thing?
No. Transport encryption protects the connection; end-to-end encryption limits what the service itself can read.
Where it appears in our guides
- This tool is covered in its category explainer.
See the full Communication explainer for the other 5 programs in this category.
How to read this page. How to read this page. Platform, licence and publisher details come from our directory data. Where an independent review, audit or survey is mentioned, it is summarised in our own words with the source named and linked; our /sources page sets out that policy. The recommendation, the trade-offs and every 'skip it if' line are our editorial judgement. We do not run benchmarks, publish measured performance figures or host installers, and every download link goes to the publisher's own site. If a detail is out of date, our About page explains how to tell us.