Czech Republic Position paper on the application of international law in cyberspace conventional means or methods of warfare, for instance if a cyber operation is designed or reasonably expected to cause injury or death to persons or damage or destruction to objects during an armed conflict.31 40. Cyber operations conducted as part of hostilities during an armed conflict must always be conducted in compliance with all relevant IHL rules and in particular with IHL basic principles of humanity and military necessity,32 distinction,33 proportionality34 and precaution.35 Compliance with these principles in a cyber context may require specific considerations as the infrastructure in cyberspace is often used for both military and civilian purposes. 41. Parties to armed conflict must carefully design and use cyber tools to distinguish between the civilian population and combatants and between civilian objects and military objectives when conducting cyber operations. Civilians and civilian objects shall be protected from being the object of attack, including those carried out by cyber means.36 Civilians are protected against attack unless and for such time as they are directly participating in hostilities. In case of doubt as to whether a person is a civilian, that person shall be presumed a civilian. Attacks shall be limited strictly to military objectives. In case of doubt as to whether cyber infrastructure that is normally used for civilian purposes is being used to effectively contribute to military action, it shall be presumed not to be so used. Foreseeable direct and indirect effects shall be taken into account when assessing the proportionality of an attack. 42. When conducting cyber operations, constant care must be taken to spare the civilian population, individual civilians and civilian objects,37 for instance to ensure protection of essential civilian 31 Rule 92, Tallinn Manual 2.0 on the International Law applicable to Cyber Operations, 2nd edition, CUP, 2017, p. 415. 32 “The law of armed conflict is a compromise based on a balance between military necessity, on the one hand, and the requirements of humanity, on the other.” in Y. Sandoz, Ch. Swinarski and B. Zimmermann (eds), Commentary on the Additional Protocols of 8 June 1977 to the Geneva Conventions of 12 August 1949, ICRC/Martinus Nijhoff Publishers, Geneva, 1987, p. 392–393 para. 1389 33 Article 48 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. 34 Article 51 para 5 letter b) and Article 57 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; „Launching an attack which may be expected to cause incidental loss of civilian life, injury to civilians, damage to civilians objects, or a combination thereof, which would be excessive in relation to the concrete and direct military advantage anticipated, is prohibited“, Rule 14 of the ICRC Customary International Humanitarian Law Study, Vol. I, Rules, Henckaerts and Doswald-Beck, CUP, 2005. 35 Articles 57–58 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; Rules 15–24 of the ICRC Customary International Humanitarian Law Study, Vol. I, Rules, Henckaerts and Doswald-Beck, CUP, 2005. 36 “The parties to the conflict must at all times distinguish between civilian objects and military objectives. Attacks may only be directed against military objectives. Attacks must not be directed against civilian objects.” (ICRC Study, rule 7); see also Article 52 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. 37 Article 57 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. 11