14. A preventive element to the obligation of due diligence also arises in the cyber context. While a state cannot be expected to monitor all ICT activities within its territory, where for example a state is aware of an identifiable risk that actors within its jurisdiction intend to conduct cyber activities that are potentially harmful to the rights of, and potentially produce serious adverse consequences for, another state, the due diligence obligation requires that reasonable and feasible measures are taken to prevent such activities or mitigate their effects. 15. Much of the consideration of the principle of due diligence in international law has been in the context of environmental obligations. While its application to cyber-operations seems clear as a general principle, its more precise parameters in this context might benefit from further consideration. For instance, in what circumstances constructive knowledge (as distinct from actual knowledge) might suffice to breach an obligation of due diligence in the cyber context, the standard to be applied in respect of constructive knowledge, as well as the scope of a preventive element to the due diligence obligation, are all matters on which there appears to be a lack of shared understanding among states. Use of Force 16. Article 2(4) of the Charter of the United Nations prohibits the threat or use of force by states against the territorial integrity or political independence of any other state. The Charter sets out two exceptions to this prohibition, namely when force is authorised by the UN Security Council and when it is used in the exercise of individual or collective selfdefence. At the OEWG, states reaffirmed that “international law, and in particular the Charter of the United Nations, is applicable and essential to maintaining peace and stability and promoting an open, secure, stable, accessible and peaceful ICT environment”.11 17. The prohibition on the use of force applies regardless of the means or weapons employed.12 In the Nicaragua case, looking at the notion of “force”, the ICJ determined that assistance to rebels in the form of the provision of weapons or logistical or other support may be regarded as a threat or use of force.13 The Court further determined that “scale and effects” are to be considered when determining whether particular actions amount to an “armed attack”.14 11 A/AC.290/2021/CRP.2, Open-Ended Working Group on Developments in the Field of Information and Telecommunications in the Context of International Security, Final Substantive Report (10 March 2021), [34]. 12 Legality of the Threat or Use of Nuclear Weapons, Advisory Opinion, International Court of Justice (ICJ), 8 July 1996, para. 39. 13 Military and Paramilitary Activities in and against Nicaragua (Nicaragua v United States of America) Merits Judgment, ICJ Reports 1986, p. 14 [228]. 14Military and Paramilitary Activities in and against Nicaragua (Nicaragua v United States of America) Merits Judgment, ICJ Reports 1986, p. 14, [195].