Czech Republic Position paper on the application of international law in cyberspace 34. Without prejudice to para 33 above, the Czech Republic takes the view that the use of a public, internationally and openly accessible network, such as the Internet, for military purposes, does not violate the law of neutrality even if it or its components are located on the territory of a neutral State, provided that doing so does not have any harmful effects on that State.27 35. A neutral State must remain impartial and may not knowingly engage in cyber activities that support the military action of one party to the international armed conflict. This means that a neutral State may not allow a party to the international armed conflict to use any cyber infrastructure located within its territory (as well as on vessels and aircrafts of the neutral State’s nationality) for military purposes or to establish a new one for such purposes. In line with para 34 above this does not apply to the use of public, internationally and openly accessible networks such as the Internet without any effect on the neutral State. 36. A neutral State is also obliged to take all feasible measures to terminate an abuse of the cyber infrastructure located within its territory (as well as on the vessels and aircrafts of its nationality) by any party to the international armed conflict. International Humanitarian Law (IHL) 37. IHL applies to cyber operations conducted in the context of both international and noninternational armed conflicts. It protects persons who do not, or no longer, take part in the hostilities, and imposes limits on the the means and methods of warfare, conduct of hostilities, and provides for the protection of civilians and civilian objects during an ongoing armed conflict. 38. Principles and rules of IHL applicable in armed conflict govern all forms of warfare and all means or methods of warfare, including those of the future.28 This is confirmed also by Article 36 of Additional Protocol I requiring States to review the lawfulness of such means and methods of warfare.29 Thus, cyber operations conducted as a part of an armed conflict are governed by IHL in the same way as any other means or methods of warfare. 39. The Czech Republic endorses the view that a cyber operation during an armed conflict, which is attributable to a State or other party to the conflict under international law, may constitute an “attack” under IHL,30 when the effects of such operation are comparable to those conducted by 27 See also Rule 151 para 4 of the Tallinn Manual 2.0 on the international law applicable to cyber operations, 2 nd edition, CUP, 2017. 28 See para 86 of the International Court of Justice in the Advisory opinion on the Legality of the Threat or Use of Nuclear Weapons, 8 July 1996, I.C.J. reports 1996. 29 “In the study, development, acquisition or adoption of a new weapon, means or method of warfare, a High Contracting Party is under an obligation to determine whether its employment would, in some or all circumstances, be prohibited by this Protocol or by any other rule of international law applicable to the High Contracting Party.” Article 36 of the Additional Protocol I to the Geneva Conventions of 12 August 1949, and relating to the Protection of Victims of International Armed Conflicts, of 8 June 1977. 30 „Attacks means acts of violence against the adversary, whether in offence or in defence“, Article 49 para 1 of the Additional Protocol I to the Geneva Conventions of 12 August 1949, and relating to the Protection of Victims of International Armed Conflicts, of 8 June 1977. 10

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