What is end-to-end encryption, and who can read your messages?

End-to-end encryption, or E2EE, is a method of secure communication where only the sender and the intended recipients can read the messages. Nobody in between, including the company that runs the service, can read them.

Here is how it works. In an E2EE service, messages are encrypted on the sender's device so that no third party, including the service provider, has the means to decrypt them. The recipients retrieve the encrypted messages and decrypt them independently on their own devices.

Compare this with the usual setup. In many non-E2EE systems, including email and many chat platforms, messages pass through intermediaries and are stored by a third-party service provider. Even if messages are encrypted only in transit, they are accessible to the service provider. Server-side disk encryption does not change that, because the provider holds the keys and can simply decrypt the information.

Many popular apps use it: WhatsApp, iMessage, Facebook Messenger and Signal use end-to-end encryption for chat messages. As of May 2025, WhatsApp was the most widely used E2EE messaging service, with over 3 billion users.

It is also debated. Computer security experts, digital freedom organisations and human rights activists advocate E2EE for its security and privacy benefits, including resisting mass surveillance. Governments, law enforcement agencies and child protection groups have expressed concerns about its impact on criminal investigations, since the services cannot hand over decrypted messages on request.