1.9 KiB
Signal
Open source application for secure messaging.
Available for Android, iOS, Linux, Mac OS X, and Windows.
TL;DR
Conversations are end-to-end encrypted.
Each and every one-to-one chat has its own unique safety number.
It allows verifying one is communicating with the correct contact.
When a safety number is marked as verified, a checkmark will appear in the chat header by that contact's name.
It will remain like that unless the safety number changes or one manually changes the verification status.
Signal notifies the user whenever a safety number has changed.
When the safety number changes, it's as if one changed the locks and keys for the conversation.
Messages sent before the safety number changed use the old locks, and as such they will not be deliverable.
SMS/MMS messaging was supported in Android systems, but it has been removed since october 2022.