Glossary
End-to-end encryption
End-to-end encryption means only the sender and the recipient hold the keys, so nobody in the middle — not the messaging company, not the network, not an attacker who intercepts the traffic — can read the message.
What it means
End-to-end encryption means only the sender and the recipient hold the keys, so nobody in the middle — not the messaging company, not the network, not an attacker who intercepts the traffic — can read the message. The encryption happens on the sender's device and the decryption happens on the recipient's device, and the service in between carries only scrambled data it cannot read.
How it works
In an end-to-end encrypted system, each device holds a private key and shares a public key with its contacts. When you send a message, your device encrypts it with the recipient's public key; only the recipient's private key can decrypt it. The service never holds the private keys, which is the whole point: a company that cannot read your messages cannot hand them to anyone else either. That is also why the limit matters: the service can still see the metadata — who messaged whom, when, how often, and from where — because the network needs that information to deliver the message. The content is hidden; the shape of the traffic is not.
Example
Imagine two fictional friends, Ana and Ben, chatting on an end-to-end encrypted app. The app's company can see that Ana messaged Ben at 9pm, that they exchanged twelve messages, and that both were in the same city. It cannot read a single word of what they said. If the company were ordered to hand over their messages, it could hand over only encrypted data — useless without the keys on Ana's and Ben's phones. But their conversation pattern — who talks to whom, and when — is still visible, and in some cases that pattern reveals more than the words would.
Common misunderstandings
The most common misunderstanding is that end-to-end encryption makes you private. It makes your message content private; it does not hide the metadata, it does not hide that you use the app, and it does not protect you if someone reads the messages on your unlocked phone. Ask two questions about any encrypted service: who holds the keys, and what metadata is still collected? The answers tell you what the encryption actually protects.
Related terms
Learn more
- What is end-to-end encryption?
- Encryption fundamentals
- Metadata and privacy
- Encryption Fundamentals Path
- Back to the full glossary
Last checked: 14 November 2026.
Frequently asked questions
Is end-to-end encryption the same as ordinary encryption?
No. Ordinary encryption may mean the service itself can read your messages, because the service holds the keys. End-to-end encryption means only the sender and recipient hold the keys, so the service in the middle cannot read them.
Can the messaging company read my end-to-end encrypted messages?
No — that is the point. The company carries only scrambled data it cannot decrypt. It can still see metadata: who messaged whom, when, and how often.
Does end-to-end encryption protect me if my phone is stolen?
Only partly. The messages in transit are protected, but if the phone is unlocked, the messages on the device can be read directly. A strong lock screen and an encrypted device backup matter just as much as the encryption in transit.