There are many messaging apps to choose from, however, many of them can be used against their users — hacked, compromised, investigated, and shared. As such, we recommend Signal, an open-source, end-to-end encrypted communication app for the most secure communication immediate messaging app. It is available for iOS, Android, Windows, Mac, and Linux.
You can download it from www.signal.org.
We are aware that many Ukrainians use Viber. Viber is a good choice (and in fact uses a modified version of Signal’s protocol). However, it is not open source, and as such, cannot be independently verified by the community for any potential avenues of compromise.
More about Signal:
State-of-the-art end-to-end encryption (powered by the open source Signal Protocol) keeps your conversations secure. We can’t read your messages or listen to your calls, and no one else can either. Privacy isn’t an optional mode — it’s just the way that Signal works. Every message, every call, every time.
OTHER MESSAGING APPS
Telegram is a great tool for general updates, but Telegram is run by a Russian company and should not be considered secure for communicating sensitive information. Additionally, Telegram stores all your contacts, groups, media, and every message you’ve ever sent or received in plaintext on their servers. The app on your phone is just a “view” onto their servers, where the data actually lives.
Almost everything you see in the app, Telegram also sees. The confusion is that Telegram does allow you to create very limited “secret chats” (no groups, synchronous, no sync) that nominally do use End to End Encryption (E2EE), even if the security of the E2EE protocol they use is dubious.
Again, not open source, and owned by Facebook, a known channel for Russian disinformation.