Up to now, the Chinese government has only made very general comments on the application of international humanitarian law to cyberspace. There are indeed Chinese academic papers concerning this issue, but the discussion of the principle of distinction is limited both in length and in academic depth. Compared with the West, research by Chinese scholars on this topic is still in a relatively preliminary stage. At present, there is no specific deconstruction or clarification of the application of the principle of distinction in cyberspace in Chinese academia. As the first paper written by Chinese scholars specifically devoted to this question, this piece provides a different perspective by injecting the positions of Chinese officials and the views of Chinese scholars. The authors aim to clarify whether the existing rules are still completely applicable in the cyber context, and if needed, to find out what kind of improvements and clarifications can be made. Weighing in on these debates, we argue that despite the potential technical challenges and uncertainties, the principle of distinction should be applied to cyberspace. It should also be carefully re-examined and clarified from the standpoint of preventing over-militarization and maximizing the protection of the interests of civilians. For human targets, the elements of combatant status identified in customary international law and relevant treaties are not well suited to the digital battlefield. Nevertheless, cyber combatants are still obligated to distinguish themselves from civilians. In applying the principle of distinction, we argue that it makes more sense to focus on substantive elements over formal elements such as carrying arms openly or having a fixed distinctive sign recognizable at a distance. In interpreting “direct participation in hostilities”, the threshold of harm requires an objective likelihood instead of mere subjective intention; the belligerent nexus should be confirmed, and the causal link should be proximate. Applying the “cyber kill chain” model by analogy helps us to grasp the whole process of direct participation in hostilities during cyber warfare. For non-human targets, all military objectives must cumulatively fulfil both the “effective contribution” and “definite military advantage” criteria, which are equally indispensable. The same requirements apply to dual-use objects. Furthermore, certain data should fall within the ambit of civilian objects.

This article presents the case for a progressive interpretation of the notion of military objectives in international humanitarian law (IHL), bringing computer data within the scope of this concept. The advent of cyber military operations has presented a dilemma as to the proper understanding of data in IHL. The emerging orthodoxy, represented by the 2013 Tallinn Manual on the International Law Applicable to Cyber Warfare, advances the argument that the intangible nature of data renders it ineligible to be an object for the purposes of the rules on targeting in IHL. This article, on the contrary, argues that because of its susceptibility to alteration and destruction, the better view is that data is an object within the meaning of this term under IHL and thus it may qualify as a military objective. The article supports this conclusion by means of a textual, systematic and teleological interpretation of the definition of military objectives found in treaty and customary law. The upshot of the analysis presented here is that data that does not meet the criteria for qualification as a military objective must be considered a civilian object, with profound implications for the protection of civilian datasets in times of armed conflict.

This article responds to the two articles published in this journal that criticise the approach taken by the International Group of Experts (IGE) who prepared the Tallinn Manual on the International Law Applicable to Cyber Warfare. Their authors took issue with the approach of the majority of the IGE over the question of whether data qualifies as an ‘object’ under international humanitarian law such that, for instance, cyber operations that target civilian data violate the prohibition on attacking civilian objects. The majority of the experts took the position that the law had not advanced that far and that pre-existing law could not be definitively interpreted to encompass data within the meaning of ‘objects’. In this article, the Director of the Tallinn Manual Project responds to the authors' criticism of the majority view by explaining and clarifying its reasoning.

The prohibition of attacks directed against civilians and civilian objects is a logical implication of the principle of distinction and an essential part of International Humanitarian Law. There is a dearth of war crimes cases focusing on unlawful attacks, perhaps because such cases have been regarded as simply too difficult to prosecute. Recently, such cases have been prosecuted before the International Criminal Tribunal for the former Yugoslavia. The article reviews these cases and the experience of the prosecutors to provide guidance for those involved in such prosecutions in future and for those involved in advising military forces or evaluating military operational conduct.