The Japanese government has started deliberations on the appropriateness of gaining a capability to counter cyberattacks by a foreign nation, a government source said Saturday.
The capability would include being able to attack an enemy's server in self-defense if Japanese government computer systems were attacked, the source said.
Japan is looking at deterrents against cyberattacks which have become increasingly sophisticated in recent years, the source said, adding Japan plans to cooperate with the United States which has sophisticated counterattack technology.
The government plans to create a "cyber defense task force" as part of the nation's Self-Defense Forces next March, the source said.
The mid-term defense capability buildup outline, adopted this week by the Cabinet of Prime Minister Shinzo Abe, also states that the government will "examine a policy option of obtaining a capability to obstruct an enemy's cyberspace use."
The Defense Ministry and other government agencies have begun compiling concrete measures to wage a counterattack, the source said.
As one technique, they are considering waging a Distributed Denial of Service Attack, by sending huge amounts of data to the server that Japan has identified as the source of the cyberattack, the source said.
For this, a senior Defense Ministry official said, it is indispensable to secure cooperation from the United States because identifying the source of a cyberattack requires very sophisticated computer technology.
But counterattacks might constitute a violation of a Japanese law banning unauthorized access to a server and computer.
And if a server from which a cyberattack was waged were in a foreign country or if Japan waged a counterattack preemptively, such action might be viewed as violating the principle of limiting responses to foreign aggression to defensive actions.
So the government plans to scrutinize legal problems that might arise in obtaining such counterattack ability, the source said.
A cyberattack refers to actions of an enemy intruding into the computer systems of a government agency, military installations or private companies online and then causing disruptions to the functions of the systems or tampering with data held at such targets.
After the Japanese government bought some islands in the Senkaku Island chain in the East China Sea from their Japanese owner in September 2012, the homepages of some central government ministries and agencies were attacked and tampered with by intruders.
Unauthorized access from Chinese sources was later found to account for a major portion of the cyberattacks.
That month the Defense Ministry drew up a guideline that says if a cyberattack is found to constitute part of military attacks by a foreign country, such action should be deemed as one of the conditions justifying Japan's invoking its rights to self-defense.