Headers trace the route followed by a message from originator to recipient, and are crucial to any email investigation. The act of substituting numbers and characters in a file so that the file is unreadable until it is decrypted. Encryption is usually done using a mathematical formula which determines how the file is decrypted. Firewall A system or combination of systems that enforces a boundary between two or more networks. Hacker Person with a strong interest in computers who enjoys learning and experimenting with them.
Hackers are usually very talented, smart people who understand computers better than others.
The term is often confused with cracker which defines someone who breaks into computers. Spoofing An attack whereby a system attempts to illicitly impersonate another system by using its IP network address. In network security, a password issued only once as a result of a challenge-response authentication process. A networking tool that can capture data as it goes through a network. Sniffers are often programmed to search for and decode specific types of information.