Used to transmit information securely over the Internet. The sender encodes it, and unless the recipient has the "key" it can't be read. PGP is a popular type of encryption.

Encryption is the process of converting data into "unreadable code" so that prying eyes cannot understand the content. Encryption is necessary as valuable & sensitive information is often sent from one computer to another via a network that technically can be accessed by anybody. It provides a degree of security should the information fall into the wrong hands.