A brief history of hacking
The original meaning of the word "hack" was born at Massachusetts Institute of Technology (MIT) in the US, and originally meant an elegant, witty or inspired way of doing almost anything.
Many early hacks took the form of elaborate practical jokes. In 1994, MIT students put a convincing replica of a campus police car on top of the Institute's Great Dome.
Over the years, the meaning changed to become a term associated with breaking into or harming of any kind of computer system.
The underground hacking network is vast, with thousands of individuals and groups, ranging from lurkers who are intrigued by hacker chat to "script kiddies" who try out hacker tools for a laugh.
Newsgroups, Internet relay chat and increasingly, peer-to-peer chat and instant messaging, are buzzing with constant hacker chatter.
Net security companies like TruSecure in the US, have the job of keeping an eye on these groups to work out which weak net spot they are planning to attack next.
The company currently tracks more than 11,000 individuals in about 900 different hacking groups and gangs.
According to some estimates, there are 5,500 Net vulnerabilities that could be used theoretically to launch an attack, but only 80 or 90 are being used
A brief history of hacking
1969: Arpanet, the forerunner of the Internet, is founded. The first network has only four nodes.
1971: First e-mail program written by Ray Tomlinson and used on Arpanet which now has 64 nodes.
1972: John Draper, also known as Captain Crunch, finds that a toy whistle given away in the cereal with the same name could be used to mimic the 2600 hertz tones phone lines used to set up long distance calls.
1980: In October, Arpanet comes to a crashing halt thanks to the accidental distribution of a virus.
1983: The internet is formed when Arpanet is split into military and civilian sections.
Wargames, a film that glamorises hacking, is released. Many hackers later claim it inspired them to start playing around with computers and networks.
1986: In August, while following up a 75 cent accounting error in the computer logs at the Lawrence Berkeley Lab at the University of California, Berkeley, network manager Clifford Stoll uncovers evidence of hackers at work. A year-long investigation results in the arrest of the five German hackers responsible.
1988: Robert Morris, a graduate student at Cornell University, sets off an Internet worm programme that quickly replicates itself to over 6,000 hosts bringing almost the whole network to a halt. Morris is arrested soon afterwards and is punished by being fined $10,000, sentenced to three years on probation and ordered to do 400 hours of community service.
1989: Kevin Mitnick is convicted of stealing software from Digital Equipment and codes for long-distance lines from US telephone company MCI. He is the first person convicted under a new law against gaining access to an interstate computer network for criminal purposes. He serves a one-year prison term.
At the Cern Laboratory for research in high-energy physics in Geneva, Tim Berners-Lee and Robert Cailliau develop the protocols that will become the world wide web.
1993: Kevin Poulsen, Ronald Austin and Justin Peterson are charged with conspiring to rig a radio phone-in competition to win prizes. The trio seized control of phone lines to the radio station ensuring only their calls got through. The group allegedly netted two Porsches, $20,000 in cash and holidays in Hawaii.
1994: A 16-year-old music student called Richard Pryce, better known by the hacker alias Datastream Cowboy, is arrested and charged with breaking into hundreds of computers including those at the Griffiths Air Force base, NASA and the Korean Atomic Research Institute. His online mentor, "Kuji", has not been found.
Also this year, a group directed by Russian hackers breaks into the computers of Citibank and transfers more than $10 million from customers' accounts. Eventually, Citibank recovered all but $400,000 of the pilfered money.
1995: In February, Kevin Mitnick is arrested for a second time. He is charged with stealing 20,000 credit card numbers. He eventually spends four years in jail and on his release his parole conditions demand that he avoid contact with computers and mobile phones.
On November 15, Christopher Pile becomes the first person to be jailed for writing and distributing a computer virus. Mr Pile, who called himself the Black Baron, was sentenced to 18 months in jail.
The US General Accounting Office reveals that US Defense Department computers sustained 250,000 attacks in 1995.
1996: Popular websites are attacked and defaced in an attempt to protest about the treatment of Kevin Mitnick.
The Internet now has over 16 million hosts and is growing rapidly.
1999: In March, the Melissa virus goes on the rampage and wreaks havoc with computers worldwide. After a short investigation, the FBI tracks down and arrests the writer of the virus, a 29-year-old New Jersey computer programmer, David L Smith.
2000: In February, some of the most popular Websites in the world such as Amazon and Yahoo are almost overwhelmed by being flooded with bogus requests for data.
In May, the ILOVEYOU virus is unleashed and clogs computers worldwide. Over the coming months, variants of the virus are released that manage to catch out companies that didn't do enough to protect themselves.
In October, Microsoft admits that its corporate network has been hacked and source code for future Windows products has been seen.