-what is Perpetrator-
Perpetrator
- The entity from the external environment that is taken to be the cause of a risk. An entity in the external environment that performs an attack, ex: hacker.

-what is Cyber Terrorist-
Cyber Terrorist
- A programmer who breaks into computer systems in order to steal or change or destroy information as a form of a cyber terrorism.

-what is Cyber Criminal-
Cyber Criminal
- are persons that committed crime using a computer and the internet to steal a person's identity or sell contraband or stalk victims or disrupt operations with malevolent programs.

source: http://thefreedictionary.com, www.tsl.state.tx.us/ld/pubs/compsecurity/glossary.html,