Transport encryption such as TLS protects each hop, but the broker or gateway in the middle decrypts and re-encrypts, so it sees the data. End-to-end encryption applies a second layer at the application level: the device encrypts the payload with a key only the final application holds, and everything between simply forwards opaque bytes. LoRaWAN builds this in with separate network and application keys, so the network operator routes packets it cannot read.
The benefit is that a compromised or merely curious intermediary learns nothing. The cost is that those intermediaries can no longer do useful work on the data, such as routing by content, validating ranges or running a rule engine. It is worth the trade for sensitive data such as health readings and camera feeds.
Part of the IoT Glossary. Spotted an error or a missing term? Tell us.