It’s here! Signal finally gets the long-requested username feature, making it possible to share your contact info without giving out your phone number. We've updated our SSD guide with directions to set it up. https://ssd.eff.org/module/how-to-use-signal
How to: Use Signal

Download location: Google Play Store, Apple App Store System requirements: Android 5 or later, iOS 13 or later Version used in this guide: Android: 7.38.6 iPhone: 7.5.1 License: GPLv3 Level: Beginner Time required: 15-20 minutes Other reading: https://signal.org/ https://support.signal.org/ https://signal.org/blog/ Table of Contents Download and Install Signal Register and Verify...

@eff Signal routes all messages through a Signal owned and operated server so they do see what IP address sends and receives each and every message. Account creation is tied to your phone number, which is likely tied to your true identity, with some financial or billing information possibly involved.

Their system is not federated, you cannot run your own inter-operable Signal server.

@DiGiLiCious Yeah, I wonder why @eff doesn't endorse @matrix instead.
@wonka @eff @matrix
Or https://delta.chat/ which is e2e over email.
Delta Chat: Delta Chat, decentralized secure messenger

Delta Chat is a decentralized and secure messenger app 💬 Reliable instant messaging with multi-profile and multi-device support ⚡️ Sign up to secure and interoperable chatmail relays 🥳 Interactive ...

@eff I'm excited for this!