Popularly known as hacking, unauthorized computer access is a crime punishable under the Computer Fraud and Abuse Act (as codified in 28 U.S.C. ¤ 1029). The law begins by defining hacking in two ways:

• Unauthorized access to computer systems
• Access that exceeds a person’s authorized limits

The prohibition thus covers trespassers who have no right at all to use a given computer, as well as those who are allowed to use a given computer but manage to access parts of the system that are off limits.