who is a hacker??

In common usage, a hacker is a person who breaks into computers. The subculture that has evolved around hackers is often referred to as the computer underground. Proponents claim to be motivated by artistic and political ends, but are often unconcerned abouthacker the use of criminal means to achieve them. While other uses of the word hacker exist that are not related to computer security (computer programmer and home computer hobbyists), they are rarely used in mainstream context.