(1) Gary McKinnon:
USA declared him as the biggest military computer hacker ever.
He hacked the security system of NASA and Pentagon. This made him one of the great
black hat hacker celebrities and got his name into the hacker's community. The nerd
 is now facing 70 years of imprisonment and is deprived from accessing internet.
He has illegally accessed 97 computers and has caused around $700,000 damage to the

(2)Robert TappanMorris:
He is the creator of first internet worm ? Morris worm? he was a student at Cornell
and from that where he started writing codes to create worms as he wanted
to know how large the internet world is. But the worm lead to the slow speed of internet
and made the systems no longer usable. There was no. ways to know how many computers were
affected but the
experts alleged that around 6000 machines. He was sent to 3 years imprisonment, 400 hours of community service and was fined $10,500. At present he is a professor at Massachusetts
institute of technology, computer science and artificial intelligence laboratory. He was the first
person prosecuted under the 1986 Computer Fraud and Abuse Act.

(3)Kevin David Mitnick:
The computer security consultant, author and a hacker was accused of many cases. He broke into the
computer of top technology and telecommunications like Nokia, Motorola, Fujitsu Siemens and sun Microsystems. He termed his activity as social engineering? to legalize his acts. He hacked the Los Angeles bus transfer system to get free rides the biggest hacking was the breaking into the DEC system to view the VMS source code (open virtual memory system which lead to the clean-up cost of
around $160,000. He also gained the full administration privileges to IBM minicomputers at the
computer learning institute in Los Angeles for a bet.

(4)Kevin Poulson:
He is best known for his takeover of the KIIS- FM phone lines, a Los Angeles based radio station. He was also known as dark Dante. The former black hat hacker is currently a senior
editor at wired news

(5) Jonathan James:
He is maestro of all hackers who broke into the server of department of defense in the year
1999 which gave him a nick name c0mrade at the age of 16. He also got into the hacking of NASA.  Stealing softwares of NASA and DoD later put him into big trouble. As he was a minor the
punishment was for for 6 months imprisonment and has to pledge that he wont be using computers