What is the primary difference of end-to-end encryption in comparison to link encryption?

The primary difference of end-to-end encryption compared to link encryption lies in the way data is protected throughout its journey across the network. End-to-end encryption focuses on securing the actual payload of the data being transmitted, ensuring that only the intended recipients can read the content, regardless of the intermediate nodes the data passes through. This means that while the headers and trailers necessary for the routing and delivery of the message remain unencrypted, the actual data remains private and secure.

In contrast, link encryption encrypts data at each individual link in the network. This method means that the data is decrypted at each hop along the network route, exposing the content to potential unauthorized access at those points. Thus, with end-to-end encryption, the data maintains confidentiality from the sender to the receiver, and only those two parties can decrypt and access the content, while the intermediate nodes do not see the information in its encrypted form.

By understanding this, it becomes clear why the statement that end-to-end encryption does not encrypt the header and trailers is a defining characteristic of its approach to securing data transmission.