7.4 - Link Encryption vs. End-to-End Encryption

Encryption is performed with different types of protection and communication levels. Two general types of encryption implemented are link encryption and end-to-end encryption. 

Link encryption, or online encryption, is provided by service providers and integrated into their network protocols. All of the information is encrypted, the packets must be decrypted at each point to the router to send the packet next. The router must decrypt the header portion of the packet, read the routing and address information within the header, and then re-encrypt it and send it on its way.

With end-to-end encryption, the packets do not need decryption and then encryption at each hop. This happens because the headers and trailers are unencrypted. Also, the devices between the beginning and the end destination read the necessary routing information and pass the packets on the way.