End-to-end encryption is a system of communication where messages are encrypted on your device and not decrypted until they reach the intended recipient. This ensures that any actor who intercepts traffic cannot read the message contents, nor can anybody with access to the central servers where data is stored.

If code is open source then it can be independently examined and audited by anyone qualified to do so, to ensure that there are no backdoors, vulnerabilities, or other security issues.

When selecting an encrypted messaging app, ensure it's fully open source, stable, actively maintained, and ideally backed by reputable developers.

Enable security settings, including contact verification, security notifications, and encryption. Disable optional non-security features such as read receipt, last online, and typing notification.

Your conversation can only be as secure as the weakest link. Often the easiest way to infiltrate a communications channel is to target the individual or node with the least protection.

Some mobile messaging apps offer a web or desktop companion. This not only increases attack surface but it has been linked to several critical security issues, and should therefore be avoided, if possible.

The risk of compromise rises exponentially, the more participants are in a group, as the attack surface increases. Periodically check that all participants are legitimate.

There are several stages where your digital communications could be monitored or intercepted. This includes: your or your participants' device, your ISP, national gateway or government logging, the messaging provider, the servers.