Recently the Yomiuri News on-line reported the following:
Against the background that the governments were examining the right of self-defense towards cyber attacks, the U.S. and its ally had deepened their concern over China.
Although the Chinese government denied it, Chinese involvement was pointed out in many examples.
The question was at which moment the right of self-defense could be invoked towards such an attack, and how and what means of force should be used, and what kind of procedure should be taken.
Japan which advocated "exclusively defensive defense" was depending on the US in its offensive retaliation strength. The Japanese government, believing in a joint management with the US, had a US-Japan agreement signed by its foreign affairs and defense authorities that would be effective starting from September 2011.
In its first "Cyber Command strategy" announced in July of the same year, the U.S. Department of Defense considered that the cyber assault from a foreign country an "act of war", and set forth a plan which did not rule out a military retaliation. Furthermore, in September a policy was set up for a joint management plan with Australia in the case of a cyber attack.
Supposedly Japan also " want an opportunity to build the same approach as Australia has" (October, Panetta the U.S. Secretary of Defense), and from now on a framework development for the Japan-U.S. joint management was expected to proceed.
However, in considering that a cyber attack was an act of war, the reality was that "an international agreement has not necessarily been reached" (Ministry of Foreign Affairs sources). In the Western countries, a motion was started that aimed at making a policy over the code of conduct in the cyberspace and over the rules of engagement; the Japanese government was also planning to get involved.
Cyber space is a new frontier for international competition. I hope it will not lead to a war because of conflicts.