There can be no doubt, computers and especially the Internet have developed the way we live our lives. Information is stored in vast databases, and through the Internet, is literally at our fingertips. Many essential services and structures are dependent on computers, and they also control physical objects such as electrical transformers, trains, pipeline pumps, chemical vats, radars and stock markets. The revolution of computers and Internet has also brought with it a potential for misuse, and cyber criminals can be a serious threat. They can do anything from breaking into protected networks, stealing anything from personal files to money, or vandalize the networks by deleting or altering information, to hijacking it and controlling the computers actions. Recognizing the potential for misuse, numerous states have issued statements on the need of regulating conduct on the Internet. The United Nations General Assembly has issued numerous statements on the possibilities of cyber abuse. For instance, fifty-third session the General Assembly recalled that technological developments could have both civilian and military application. They also stated that the use of information technologies could affect the interests of the whole international community, and disturb international stability and security. In its fifty-fifth session it called on states to criminalize cyber abuse and deny their territory from being used as a safe haven. There is also an international convention on Cybercrime which pursues a common criminal policy to protect society against cybercrime, by adopting appropriate legislation and development international co-operation. But as the U.N. General Assembly noted, the technological developments can have both civilian and military applications. In recent years numerous countries have established their own cyber branches/units within the military. To name a few examples, the USA has the US Cyber Command, China’s People’s Liberation Army has a cyber-division called Blue Team, Norway has Cyberforsvaret, and the United Kingdom’s Ministry of Defence has started recruiting personnel for a new cyber unit. The USA has declared that it reserves the right to use all necessary means, including military to defend against hostile acts in cyberspace. Cyber-attacks have the potential to cause a lot of damage. There have already been large scale cyber operations that have had a significant effect on countries, but so far the effects have not been devastating. The most notorious cyber-attacks in history are “Robert Tappan Morris and the Morris Worm (1988), MafiaBoy causes $1 billion dollars in damages (2000), Google China hit by cyber-attack (2009, Teen hacks NASA and US Defense Department 1999. Recently some cases “in June 2016 that Russian intelligence had hacked a Democratic National Committee (DNC) server in an attempt to steal opposition research on Republican presidential candidate Donald Trump, in 2010 in Iran targeted through cyber-attack. In early 2007, Estonia was the recipient of repeated denial-of-service attacks.