Cyber attacks have become a grave threat to international peace and security. Northeast Asia is a critical point of many of these cyber operations. First, South Korea has been the target of cyber attacks from North Korea. Second, there are harsh debates on this matter between the US and China. While the United States have expressed their concerns about the growing threat of cyber intrusions from China, the People’s Republic of China has blamed the US for attacks against their respective computer networks. From the perspective of the jus ad bellum, potential cyber attacks raise a number of difficult and complex issues. The following article examines which cyber operations amount to the use of force as stipulated in Article 2(4) of the UN Charter and discusses the conditions under which type of cyber attacks could trigger the right to self-defense. In addition, other available remedies outside the framework of Article 51 of the UN Charter will be discussed.

More than a century before Grotius wrote his famous work on international law, his countryman Desiderius Erasmus of Rotterdam laid the foundations for the modern critique of war. In several writings, especially those published in the period 1515- 1517, the “prince of humanists”brilliantly and devastatingly condemned war not only on Christian but also on secular/rational grounds. His graphic depiction of the miseries of war, together with his impassionate plea for its avoidance, remains unparalleled. Erasmus argued as a moralist and educator rather than as a political theorist or statesman. If any single individual in the modern world can be credited with“ the invention of peace,”the honour belongs to Erasmus rather than Kant whose essay on perpetual peace was published nearly three centuries later.