What Is End-to-End Encryption?

End-to-end encryption means a message is encrypted in a way that only the sender and intended recipient can read its contents. The service carrying the message is not supposed to be able to read the plain text in the middle.

How It Differs From Ordinary Encryption

Many services use encryption in transit, which protects data while it travels between your device and the service. That is good, but it still allows the service itself to access the content in normal readable form.

End-to-end encryption goes further by keeping the readable message limited to the endpoints.

What It Does Not Automatically Hide

Even when message content is protected, other information may still exist. Metadata such as who contacted whom, when, and how often can still be visible depending on the service design.

That is why end-to-end encryption is powerful without being the same thing as total invisibility.

Why Device Security Still Matters

If your device is compromised or your messages are backed up in a less secure way, end-to-end encryption alone may not solve the problem. The whole system matters, not just the message path.

Summary

End-to-end encryption means only the communicating endpoints should be able to read the message contents. It offers stronger privacy than ordinary in-transit encryption, but it does not eliminate every other risk. For the foundation, see What Is Encryption? and What Is Metadata?.