1 See UN High-Level Committee on Management, Principles on Handling of Personal Information, October 2018, available at: https://unsceb.org/personal-data-protection-and-privacy-principles (all internet references were accessed in February 2022).

2 See, for example, Office of the UN High Commissioner for Refugees, Policy on the Protection of Personal Data of Persons of Concern to UNHCR, May 2015, available at: www.refworld.org/docid/55643c1d4.html; UN, Data Strategy of the Secretary-General for Action by Everyone, Everywhere 2020–2022, 2020, available at: www.un.org/en/content/datastrategy/images/pdf/UN_SG_Data-Strategy.pdf.

3 Report of the Panel of Experts Established Pursuant to Resolution 1874 (2009), UN Doc. S/2020/840, 28 August 2020, paras 118–121. See also Report of the Panel of Experts Established Pursuant to Resolution 1874 (2009), UN Doc. S/2020/151, 2 March 2020, Annexes 28–30.

4 “The Cyber Attack the UN Tried to Keep under Wraps”, The New Humanitarian, 29 January 2020, available at: www.thenewhumanitarian.org/investigation/2020/01/29/united-nations-cyber-attack; “United Nations Agency ‘Hacking Attack’ Investigated”, BBC News, 21 November 2021, available at: www.bbc.co.uk/news/technology-15951883.

5 “Netherlands Defence Intelligence and Security Service Disrupts Russian Cyber Operation Targeting OPCW”, ASD News, 4 October 2018, available at: www.asdnews.com/news/defense/2018/10/04/netherlands-defence-intelligence-security-service-disrupts-russian-cyber-operation-targeting-opcw.

6 WHO, “WHO Reports Fivefold Increase in Cyber Attacks, Urges Vigilance”, 23 April 2020, availabe at: www.who.int/news/item/23-04-2020-who-reports-fivefold-increase-in-cyber-attacks-urges-vigilance; “Elite Hackers Target WHO as Coronavirus Cyberattacks Spike”, Reuters, 23 March 2020, available at: www.reuters.com/article/us-health-coronavirus-who-hack-exclusive-idUSKBN21A3BN.

7 In the authors’ view, the ICRC is an international organization possessing international legal personality. Various States and IOs have recognized the ICRC's international legal personality; for a discussion of this practice, see Debuf, Els, “Tools to Do the Job: The ICRC's Legal Status, Privileges and Immunities”, International Review of the Red Cross, Vol. 97, No. 897–898, 2015, pp. 321–329CrossRefGoogle Scholar.

8 ICRC, “Cyber-Attack on the ICRC: What We Know”, 21 January 2022, available at: https://icrc.org/en/document/cyber-attack-icrc-what-we-know; ICRC, “ICRC Cyber-Attack: Sharing our Analysis”, 16 February 2022, available at: www.icrc.org/en/document/icrc-cyber-attack-analysis.

9 Ibid. (“Were data sets copied and exported? We must presume so. We know that the hackers were inside our systems and therefore had the capacity to copy and export it.”)

10 See, generally, Russell Buchan, Cyber Espionage and International Law, Hart, Oxford, 2018; Russell Buchan and Iñaki Navarrete, “Cyber Espionage and International Law”, in Nicholas Tsagourias and Russell Buchan (eds), Research Handbook on International Law and Cyberspace, Edward Elgar, Cheltenham, 2021; Asaf Lubin, “The Liberty to Spy”, Harvard International Law Journal, Vol. 61, No. 1, 2020; Craig Forcese, “Spies Without Borders: International Law and Intelligence Collection”, Journal of National Security Law and Policy, Vol. 5, No. 1, 2011.

11 In this article, we assume that the hacking is committed by a State or is attributable to a State. On attribution in the context of IOs, see International Law Commission (ILC), Draft Articles on the Responsibility of International Organizations, 2011 (DARIO). On cyber attribution, see Tsagourias, Nicholas and Farrell, Michael, “Cyber Attribution: Technical and Legal Approaches and Challenges”, European Journal of International Law, Vol. 31, No. 3, 2020CrossRefGoogle Scholar.

12 “Both the basis for and the scope of this immunity, which is aimed at ensuring that the UN can function completely independently and thus serves a legitimate purpose, are therefore different from those underlying the immunity from jurisdiction of foreign states”: Supreme Court of the Netherlands, Stichting Mothers of Srebrenica and Others v. Netherlands and United Nations, LJN: BW1999, ILDC 1760 (NL, 2012), Final Appeal Judgment, 13 April 2012, para. 4.2. “International organizations enjoy privileges and immunities entirely because they are necessary for the fulfilment of their purposes and functions”: Chittharanjan Felix Amerasinghe, Principles of the Institutional Law of International Organizations, Cambridge University Press, Cambridge, 2006, p. 316. See also C. Wilfred Jenks, International Immunities, Stevens & Sons and Oceana, London, 1961, p. 18; Council of Europe, Committee of Ministers, European Committee on Legal Cooperation: Addendum: Privileges and Immunities of International Organizations and Persons Connected with Them, 9 July 1969, p. 4; Wickremasinghe, Chanaka, “International Organizations or Institutions: Immunities before National Courts”, Max Planck Encyclopedia of International Law, 2009Google Scholar, para. 1.

13 In relation to the UN's specialized agencies, see Convention on the Privileges and Immunities of Specialized Agencies, 1947.

14 August Reinisch, “Privileges and Immunities”, in Jacob Katz Cogan, Ian Hurd and Ian Johnstone (eds), The Oxford Handbook of International Organizations, Oxford University Press, Oxford, 2016, p. 1058.

15 “[T]he immunity of international organizations, within the framework of their functional restrictions, is to be regarded in principle as absolute”: Austrian Supreme Court, Firma Baumeister Ing. Richard L v. O, 10 Ob 53/04 y, ILDC 362 (AT 2004), 14 December 2004, para. 12. See also August Reinisch and Peter Bachmayer, The Convention on the Privileges and Immunities of the United Nations and Its Specialized Agencies: A Commentary, Oxford University Press, Oxford, 2016, p. 67 (“In practice an unqualified, general immunity … is often regarded as absolute immunity”).

16 See, for example, General Agreement on Privileges and Immunities of the Council of Europe, 1949; Agreement on Privileges and Immunities of the Organization of American States, 1949; Treaty Establishing the Central American Institute of Public Administration, 1954; Agreement Establishing the World Trade Organization, 1995; Convention on the Privileges and Immunities of Specialized Agencies, 1947.

17 E. Debuf, above note 7, p. 333.

18 Supreme Court of Canada, World Bank Group v. Wallace, [2016] 1 SCR 207, 29 April 2016, para. 78.

19 Blank, Laurie, “The Limits of Inviolability: The Parameters for Protection of United Nations Facilities during Armed Conflict”, International Law Studies, Vol. 93, 2017, p. 55Google Scholar.

20 UN General Assembly, The Practice of the United Nations, the Specialized Agencies and the International Atomic Energy Agency concerning their Status, Privileges and Immunities: Study Prepared by the Secretariat, UN Doc. A/CN.4/L.118, 8 March 1967. See also A. Reinisch and P. Bachmayer, above note 15, p. 127.

21 With regard to the diplomatic and consular missions of States, some authors have argued that their premises encompass the computer networks and systems supported by cyber infrastructure that is located within the missions’ physical premises. See Michael N. Schmitt, Tallinn Manual 2.0 on the International Law Applicable to Cyber Operations, Cambridge University Press, Cambridge, 2017 (Tallinn Manual 2.0), Rule 39; R. Buchan, above note 10, p. 73.

22 R. Buchan, above note 10, p. 73.

23 “We also feel it is important to clarify that this was a targeted, direct cyber-attack on ICRC servers, not the company that hosted them. We manage the data and applications on these servers, not the hosting company”: ICRC, “Cyber-Attack on the ICRC”, above note 8.

24 Supreme Court of Canada, World Bank Group, above note 18, para. 78.

25 UK Court of Appeal, R (Bancoult No. 3) v. Secretary of State for Foreign and Commonwealth Affairs, [2014] EWCA Civ. 708, 23 May 2014, para. 58.

26 “UN to Investigate GCHQ, MI5 Spying on Foreign Delegates at Climate Summit Talks”, RT, 5 November 2010, available at: www.rt.com/uk/202147-uk-climate-summit-spying/; “U.N. to Britain: If Spying on Us, Stop It”, UPI, 26 February 2004, available at: www.upi.com/Defense-News/2004/02/26/UN-to-Britain-If-spying-on-us-stop-it/31241077833950/; UN, Daily Press Briefing by the Office of the Spokesman for the Secretary-General, 29 November 2010, available at: www.un.org/press/en/2010/db101129.doc.htm.

27 A. Reinisch and P. Bachmayer, above note 15, p. 132.

28 Report of the Commissioner-General of UNRWA to the General Assembly, 1 January to 31 December 2013, UN Doc. A/69/13, 2014, para. 58.

29 Supreme Court of the State of New York, Appellate Division, Shamsee v. Shamsee, 428 NYS2d 33, 36 (2d Dep't 1980), (1980) UNJYB, 18 October 1979, p. 222 (“[T]he Pension Fund is an organ of the United Nations, subject to regulation by the General Assembly, and … its assets, although held separately from other United Nations property, are the property of that international organization”).

30 Supreme Court of Canada, World Bank Group, above note 18, para. 73. The UN Secretary-General defines archives as “records to be permanently preserved for their administrative, fiscal, legal, historical or informational value”: UN Secretariat, “Secretary-General's Bulletin: Record-Keeping and Management of United Nations Archives”, ST/SGB/2007/5, 2007.

31 UK Supreme Court, R (on the Application of Bancoult No. 3) v. Secretary of State for Foreign and Commonwealth Affairs, [2018] UKSC 3, 8 February 2018, para. 68; Tallinn Manual 2.0, above note 21, p. 220; A. Reinisch and P. Bachmayer, above note 15, pp. 161–162; “Letter from the Assistant Secretary-General for Legal Affairs to the Minister Counsellor of a Permanent Mission to the United Nations”, 5 September 2007. The UN Secretary-General defines documents as “any data or information, regardless of its form or medium, which is or has been electronically generated by, transmitted via, received by, processed by, or represented in an ICT resource”: UN Secretariat, “Secretary-General's Bulletin: Use of Information and Communication Technology Resources and Data”, ST/SGB/2004/15, 2004. “All records, including electronic records and e-mail records, created or received by a staff member in connection with or as a result of the official work of the United Nations, are the property of the United Nations”: UN Secretariat, above note 30.

32 “[With regard to Section 4] we are thus talking about not only all the Organization's own documents but also those held by it, in other words those in its safekeeping”: Leonardo Diaz-Gonzalez, Fifth Report on Relations between States and International Organizations, UN Doc. A/CN.4/432, 11 May 1990, p. 4. See also A. Reinisch and P. Bachmayer, above note 15, pp. 163–165.

33 “What is it that identifies a document as belonging to the archives or documents of the mission, as opposed to some other organ of the sending state? … The test is not their location, for they are protected ‘wherever they may be’. It must necessarily be whether they are under the control of the mission's personnel”: UK Supreme Court, Bancoult No. 3, above note 31, para. 68.

34 Ibid.

35 Higgins, Rosalyn, Problems and Process: International Law and How We Use It, Oxford University Press, Oxford, 1994, p. 93Google Scholar.

36 Eileen Denza, Diplomatic Law: Commentary on the Vienna Convention on Diplomatic Relations, Oxford University Press, Oxford, 2016, p. 194.

37 Vienna Convention on Diplomatic Relations, 1961 (VCDR), Art. 27(4).

38 R. Buchan, above note 10, p. 87.

39 VCDR, Art. 27(3).

40 Choi, Won-Mog, “Diplomatic and Consular Law in the Internet Age”, Singapore Year Book of International Law, Vol. 10, 2006, p. 131Google Scholar.

41 A. Sam Muller, International Organizations and Their Host States: Aspects of their Legal Relationship, Brill, Leiden, 1995, p. 22.

42 Ibid., Chap. 6; Miller, Anthony J., “Privileges and Immunities of United Nations Officials”, International Organizations Law Review, Vol. 4, No. 2, 2007, p. 170CrossRefGoogle Scholar.

43 Pieter H. F. Bekker, The Legal Position of Intergovernmental Organizations: A Functional Necessity Analysis of Their Legal Status and Immunities, Martinus Nijhoff, Leiden, 1994, p. 136.

44 Vienna Convention on the Law of Treaties, 1969 (VCLT), Art. 34.

45 Michael Wood, “Do International Organizations Enjoy Immunity under Customary International Law?”, in Niels M. Blokker and Nico J. Schrijver (ed.), Immunity of International Organizations, Brill, Leiden, 2015, p. 30; Edward Chukwuemeke Okeke, Jurisdictional Immunities of States and International Organizations, Oxford University Press, Oxford, 2018, p. 269. For a more nuanced approach, see Niels M. Blokker, “Jurisdictional Immunities of International Organisations – Origins, Fundamentals and Challenges”, in Tom Ruys, Nicolas Angelet and Luca Ferro (eds), The Cambridge Handbook of Immunities and International Law, Cambridge University Press, Cambridge, 2019, pp. 194–197.

46 For example, the NATO Constitution and the Warsaw Treaty Pact Organization Charter.

47 “[T]he General Convention's provisions on jurisdictional immunity have been applied to other organizations and non-member states through the development of similar treaties and customary international law”: Brower, Charles H. II, “International Immunities: Some Dissident Views on the Role of Municipal Courts”, Virginia Journal of International Law, Vol. 41, No. 1, 2001, p. 22Google Scholar. Amerasinghe explains that the CPIUN and the Specialized Agencies Convention reflect an “incipient customary law of international privileges and immunities” and that there is “a presumption that many of the privileges and immunities incorporated in the two general conventions are generally what are required for this purpose”: C. F. Amerasinghe, above note 12, p. 346. See also Giorgio Gaja, “Jurisdictional Immunity of International Organizations”, Yearbook of the International Law Commission, Vol. 2, Part 2, 2006, p. 202; Christian Dominicé, “L'immunité de juridiction et d'exécution des Organisations Internationales”, Recueil des Cours, Vol. 187, 1984, pp. 174–177 (“Le probléme de la coutume”), 219–225 (“La question de la coutume”); James Crawford, Brownlie's Principles of Public International Law, Oxford University Press, Oxford, 2019, pp. 164–166.

48 ICJ, North Sea Continental Shelf Cases, Judgment, [1969] ICJ Rep. 3, 20 February 1969, para. 72.

49 Statute of the International Court of Justice, 1945, Art. 38(1)(b).

50 ICJ, North Sea, above note 48, para. 71; ICJ, Case Concerning Military and Paramilitary Activities in and against Nicaragua (Nicaragua v. United States of America), Judgment (Merits), [1986] ICJ Rep. 14, 17 June 1986, para. 184.

51 ICJ, North Sea, above note 48, para. 73. See also ICJ, Legality of the Threat or Use of Nuclear Weapons, Advisory Opinion, [1996] ICJ Rep. 226, 8 July 1996, para. 82 (citing “the extent of the accession” to the Hague and Geneva treaties as confirming their CIL status). “The number of parties to a treaty may be an important factor in determining whether particular rules set forth therein reflect customary international law; treaties that have obtained near-universal acceptance may be seen as particularly indicative in this respect”: ILC, Draft Conclusions on Identification of Customary International Law, with Commentaries, 2018, Conclusion 11, Commentary para. 3.

52 Special Court for Sierra Leone, Prosecutor v. Sam Hinga Norman, Case No. SCSL-2004-14-AR72(E), Decision on Preliminary Motion Based on Lack of Jurisdiction (Child Recruitment), 31 May 2004, paras 17–20 (referring to the “huge acceptance, the highest acceptance of all international conventions” as indicating that the relevant provisions of the Convention on the Rights of the Child have passed into CIL).

53 “Certainly, there are important, modern authorities for the proposition that the Geneva Conventions of 1949 have largely become expressions of customary international law, and both Parties to this case agree. The mere fact that they have obtained nearly universal acceptance supports this conclusion”: Eritrea–Ethiopia Claims Commission, Partial Award: Prisoners of War, Ethiopia's Claim 4, UNRIAA, Vol. 26, 1 July 2003, para. 31 (citations omitted).

54 “[A] treaty will only constitute sufficient proof of a norm of customary international law if an overwhelming majority of States have ratified the treaty, and those States uniformly and consistently act in accordance with its principles”: District Court for the Eastern District of Virginia, United States v. Hasan and Ors, Decision on Motion to Dismiss, No. 2:10cr56, ILDC 1586 (US 2010), 29 October 2010, para. 87. The Court considered the definition of piracy in the UN Convention on the Law of the Sea to be reflective of CIL on the basis that 161 States had ratified it, which represented the “overwhelming majority”: ibid., para. 89. See, generally, Ryngaert, Cedric M. J. and Siccama, Duco W. Hora, “Ascertaining Customary International Law: An Inquiry into the Methods Used by Domestic Courts”, Netherlands International Law Review, Vol. 65, No. 1, 2018, pp. 6–10CrossRefGoogle Scholar.

55 Crawford explains that there must be “a presumption of opinio juris from wide participation in a treaty, at least in normative terms”: Crawford, James, “Chance, Order, Change: The Course of International Law”, Recueil des Cours, Vol. 365, 2013Google Scholar, para. 167. “[P]articipation in a treaty with a fundamentally norm-creating character (such as an IHL treaty) counts as practice capable of supporting the development of parallel rules of customary law”: Marco Sassòli, International Humanitarian Law: Rules, Controversies, and Solutions to Problems Arising in Warfare, Edward Elgar, Cheltenham, 2019, para. 4.40. See also Baxter, Richard R., “Multilateral Treaties as Evidence of Customary International Law”, British Yearbook of International Law, Vol. 41, 1965–66, p. 275Google Scholar; Hugh Thirlway, International Customary Law and Codification, A. W. Sijthoff, Leiden, 1972, p. 89; Anthony D'Amato, The Concept of Custom in International Law, Cornell University Press, London and Ithaca, NY, 1971, p. 104.

56 It is interesting to note that in 1967 the UN Legal Counsel opined that “the standards and principles of the Convention have been so widely accepted that they have now become a part of the general international law governing the relations of States and the United Nations”, and this was also correct in relation to NMSs; “Question of Privileges and Immunities of the United Nations, of Representatives of Member States and of Officials of the Organization: Statement made by the Legal Counsel at the 1016th Meeting of the Sixth Committee of the General Assembly on 6 December 1967”, United Nations Juridical Yearbook, 1967, p. 314.

57 “[I]n some cases it may be that frequent repetition in widely accepted treaties evinces a recognition by the international community as a whole that a rule is one of general, and not just particular, law”: International Law Association, Committee on Formation of Customary (General) International Law: Final Report, 2000, Rule 25, Commentary para. 5. “The repetition in two or more codification conventions of the substance of the same norm may be an important element in establishing the existence of that norm as a customary rule of general international law”: Institut de Droit International, Problems Arising from a Succession of Codification Conventions on a Particular Subject, Lisbon, 1995, Rule 12. “The fact that a rule is set forth in a number of treaties may, but does not necessarily, indicate that the treaty rule reflects a rule of customary international law”: ILC, above note 51, Conclusion 11(2).

58 Dinstein, Yoram, “The Interaction between Customary International Law and Treaties”, Recueil des Cours, Vol. 322, 2006, pp. 299–300Google Scholar.

59 Alison Duxbury, “Intersections between Diplomatic Immunities and the Immunities of International Organizations”, in Paul Behrens (ed.), Diplomatic Law in a New Millennium, Oxford University Press, Oxford, 2017.

60 ICJ, Arrest Warrant of 11 April 2000 (Democratic Republic of the Congo v. Belgium), Judgment, [2002] ICJ Rep. 3, 14 February 2002, para. 52; ICJ, Certain Questions of Mutual Assistance in Criminal Matters (Djibouti v. France), Judgment, [2008] ICJ Rep. 177, 4 June 2008, para. 174; ICJ, United States Diplomatic and Consular Staff in Tehran, Judgment, [1980] ICJ Rep. 3, 24 May 1980, paras 62, 69.

61 Accord du 11 Mars 1946 entre le Conseil Fédéral Suisse et l'Organisation Internationale du Travail pour régler le Statut Juridique de cette Organisation en Suisse, available at: www.fedlex.admin.ch/eli/cc/1956/1103_1182_1194/fr.

62 Accord entre le Conseil Fédéral Suisse et l'Association Européenne de Libre-échange pour déterminer le Statut Juridique de cette Association en Suisse, available at: www.fedlex.admin.ch/eli/cc/1961/749_763_779/fr .

63 European Organization for Nuclear Research, Headquarters Agreement, CERN/115 Rev. 2, 11 February 1955, available at: https://cds.cern.ch/record/21737/files/CM-P00074863-e.pdf.

64 Accord entre le Conseil Fédéral Suisse et l'Organisation Mondiale de la Santé, pour régler le Statut Juridique de cette Organisation en Suisse Conclu le 21 août 1948, available at: www.fedlex.admin.ch/eli/cc/1956/1120_1198_1210/fr.

65 Supreme Court of the Netherlands, A. S. v. Iran–United States Claims Tribunal, RvdW (1986) No. 20, NJ (1986) No. 438, 20 December 1985, Netherlands Yearbook of International Law, Vol. 18, 1987, p. 360.

66 Haggai Carmon, “A Jerusalem Court Ruling: The European Commission is Immune to a Commercial Lawsuit”, Diplomatic/Consular Law and Sovereign Immunity in Israel and Worldwide, available at: http://diplomaticlaw.com/blog/?p=100.

67 J. Crawford, above note 47, pp. 164–166.

68 ILC, above note 51, Conclusion 4(2), Commentary paras 5, 6. See also Daugirdas, Kristina, “International Organizations and the Creation of Customary International Law”, European Journal of International Law, Vol. 31, No. 1, 2020, p. 201CrossRefGoogle Scholar; C. Dominicé, above note 47, pp. 220–225.

69 “[T]he privileges and immunities of an international organization derive from its legal status as an international person”: E. C. Okeke, above note 45, p. 253. See also Bordin, Fernando Lusa, “To What Immunities are International Organizations Entitled under General International Law? Thoughts on Jam v IFC and the ‘Default Rules’ of IO Immunity”, Questions in International Law, Vol. 72, No. 1, 2020, p. 5Google Scholar. Italian case law has derived immunities from the legal personality of an IO. See Italian Court of Cassation, Christiani v. ILAI, Judgment No. 5819/1985, Rivista di Diritto Internazionale, 1986, p. 149. Dominicé takes the view that an IO with legal personality and whose MSs have granted it jurisdictional immunities as a matter of customary law enjoys the same immunities vis-à-vis NMSs (third States), but this may not be the case if the IO does not enjoy immunities vis-à-vis its MSs; C. Dominicé, above note 47, pp. 222–224.

70 Finn Seyersted, Objective International Personality of Intergovernmental Organisations: Do Their Capacities Really Depend upon their Constitutions?, Copenhagen, 1963, pp. 9–10; C. W. Jenks, above note 12, p. 34; Philippe Sands and Pierre Klein, Bowett's Law of International Institutions, Sweet and Maxwell, London, 2009, p. 490; Nigel D. White, The Law of International Organisations, Manchester University Press, Manchester, 2017, pp. 101–120.

71 ICJ, Reparation for Injuries Suffered in the Service of the United Nations, Advisory Opinion, [1949] ICJ Rep. 174, 11 April 1949, pp. 177–185. See also DARIO, above note 11, Art. 2, Commentary para. 9.

72 “There are those who take the view that the international legal personality of an organization is opposable only to those who have ‘recognised’ the organization, in the sense of being a member of the organization or engaging in some transaction with it, or granting privileges to it. But this is to ignore the objective legal reality of international personality. If the attributes are there, personality exists. It is not a matter of recognition. It is a matter of objective reality”: R. Higgins, above note 35, pp. 47–48. “[T]he personality of international organizations is in fact objective, which means that it is opposable to non-members and that non-members are bound to accept that organization as a separate legal person”: Dapo Akande, “International Organizations”, in Malcolm Evans (ed.), International Law, Oxford University Press, Oxford, 2018, p. 233. The United States claims that the objective legal personality of an IO depends on the size of its membership: “An international organization with substantial membership is a person in international law even in relation to states not members of the organization. However, a state does not have to recognize the legal personality of an organization of which it is not a member, which has few members, or which is regional in scope in a region to which the state does not belong.” “Restatement (Third) of Foreign Relations Law of the United States”, American Law Institute, 1987, Section 223, Comment (e). However, as Amerasinghe explains, once the legal personality of an IO is objectively established, there is no need to inquire into the size of its membership: C. F. Amerasinghe, above note 12, pp. 86–91.

73 J. Crawford, above note 47, p. 163; F. L. Bordin, above note 69, pp. 8–15; N. D. White, above note 70, p. 117.

74 Statute of the International Court of Justice, 1945, Art. 38(1)(c). See also ICJ, Land and Maritime Boundary between Cameroon and Nigeria, Judgment (Preliminary Objections), [1998] ICJ Rep. 275, 11 June 1998, para. 38; ICJ, Certain Norwegian Loans, [1957] ICJ Rep. 9, 6 July 1957, p. 53 (Separate Opinion of Judge Lauterpacht) (“Unquestionably, the obligation to act in accordance with good faith, being a general principle of law, is also part of international law”); Bin Cheng, General Principles of Law as Applied by International Courts and Tribunals, Cambridge University Press, Cambridge, 1953, Part II; Virally, Michel, “Good Faith in Public International Law”, American Journal of International Law, Vol. 77, No. 1, 1983, p. 130CrossRefGoogle Scholar; Robert Kolb, Good Faith in International Law, Hart, Oxford, 2017. For a more critical approach, see Elisabeth Zoller, La bonne foi en droit international public, A. Pédone, Paris, 1977.

75 John F. O'Connor, Good Faith in International Law, Dartmouth, Aldershot, 1991, pp. 18–19, 124.

76 According to Schwarzenberger, GF is “a fundamental principle which can be eradicated from international law only at the price of the destruction of international law itself [and] forms necessarily part of the international public order. This consideration alone would suffice to qualify good faith as one of the fundamental principles of international law”; Georg Schwarzenberger, “The Fundamental Principles of International Law”, Recueil des Cours, Vol. 87, 1955, p. 326. See also B. Cheng, above note 74, p. 105; ILC, First Report on General Principles of Law, UN Doc. A/CN.4/732, 2019, para. 154.

77 ICJ, Nuclear Tests (Australia and New Zealand v. France), Judgment (Questions of Jurisdiction and/or Admissibility), [1974] ICJ Rep. 457, 20 December 1974, para. 46; Guillaume Futhazar and Anne Peters, “Good Faith”, in Jorge E Viñuales (ed.), The UN Friendly Relations Declaration at 50: An Assessment of the Fundamental Principles of International Law, Cambridge University Press, Cambridge, 2020, p. 191.

78 “Good faith is a supreme principle, which governs legal relations in all of their aspects and content”: International Centre for Settlement of Investment Disputes, Inceysa Vallisoletana s.l. v. Republic of El Salvador, ICSID Case No. ARB/03/26, Award of 2 August 2006, para. 230. See also ICJ, Military and Paramilitary Activities in and against Nicaragua (Nicaragua v. United States of America), Jurisdiction of the Court and Admissibility of the Application, [1984] ICJ Rep. 392, 29 November 1984, para. 60; ILC, above note 76, para. 161.

79 Permanent Court of International Justice, Case Concerning Certain German Interests in Polish Upper Silesia, Judgment No. 7, [1926] PCIJ Series A, 25 May 1926, pp. 1, 39–40; Court of First Instance of the European Communities, Opel Austria GmbH v. Council, Case No. T-115/94, [1997] ECR II-39, 22 January 1997, paras 24, 89–90.

80 ICJ, Delimitation of Maritime Boundary in Gulf of Maine Area, Judgment, [1984] ICJ Rep. 246, 12 October 1984, para. 79; World Trade Organization, Appellate Body, United States – Import Prohibition of Certain Shrimp and Shrimp Products, WT/DS58/AB/R, 12 October 1998, para. 158; ILC, above note 76, paras 142–162.

81 ICJ, Reparation for Injuries, above note 71 (where the ICJ viewed the UN (as an IO) and States as “two political entities, equal in law, similar in form, and both the direct subjects of international law”: pp. 177–179). Also see ICJ, Interpretation of the Agreement of 25 March 1951 between the WHO and Egypt, Advisory Opinion, [1980] ICJ Rep. 73, 20 December 1980, para. 37 (“International organizations are subjects of international law, and, as such, are bound by any obligations incumbent upon them under general rules of international law”).

82 “It is clear to this Tribunal that the investment made by Inceysa in the territory of El Salvador, which gave rise to the present dispute, was made in violation of the principle of good faith”: International Centre for Settlement of Investment Disputes, Inceysa Vallisoletana s.l., above note 78, para. 234.

83 ICJ, North Sea, above note 48, p. 44; ICJ, Fisheries Case (United Kingdom v. Norway) (Merits), [1951] ICJ Rep. 116, 18 December 1951, p. 131.

84 M. Virally, above note 74, p. 134: “[G]ood faith is often hidden by the more precise rules it has generated (e.g. pacta sunt servanda), so that it becomes no longer necessary to rely upon it expressly for ordinary practical purposes. But even in such instances, general principles retain their full value as the ratio legis to which one may profitably turn in difficult cases.” See also Alain Pellet and Daniel Müller, “Article 38”, in Andreas Zimmermann and Christian J. Tams (eds.), The Statute of the International Court of Justice: A Commentary, Oxford University Press, Oxford, 2019, para. 297.

85 Ronald Dworkin, Taking Rights Seriously, Duckworth, London, 1978, Chaps 2, 3; Raz, Joseph, “Legal Principles and the Limits of Law”, Yale Law Journal, Vol. 81, No. 5, 1972, p. 823CrossRefGoogle Scholar.

86 In relation to the EU, see Court of Justice of the European Union, Greece v. Commission, Case No. C-203/07 P, [2008] ECR I-8161, 2008, para. 83 (Opinion of Advocate-General Mazák).

87 For example, the EU or Section 30 of the CPIUN.

88 See Article 2(2) of the UN Charter in Bruno Simma, Daniel-Erasmus Khan, Georg Nolte and Andreas Paulus (eds), The Charter of the United Nations: A Commentary, Oxford University Press, Oxford, 2012. See also UNGA Res. 2625 (XXV), “Declaration on Principles of International Law concerning Friendly Relations and Co-operation among States in Accordance with the Charter of the United Nations”, 24 October 1970, Principle 4.

89 See also Articles 13(2) and 24(3) of the Treaty on European Union. See, generally, Geert De Baere and Timothy Roes, “EU Loyalty as Good Faith”, International and Comparative Law Quarterly, Vol. 64, No. 4, 2015.

90 See Articles 26 and 31 of the VCLT and of the Vienna Convention on the Law of Treaties between States and International Organizations or between International Organizations, 1986.

91 ICJ, WHO/Egypt, above note 81, para. 48.

92 See ibid., pp. 155–162 (Separate Opinion of Judge Ago).

93 The ICJ explained that the very essence of these relations “is a body of mutual obligations of co-operation and good faith”: ibid., para. 43. See also ibid., p. 158 (Separate Opinion of Judge Ago).

94 Ibid., paras 46, 48.

95 Permanent Court of International Justice, Competence of the International Labour Organization to Regulate, Incidentally, the Personal Work of the Employer, Advisory Opinion No. 13, [1926] PCIJ Series B, 23 July 1926, p. 18.

96 ICJ, Reparation for Injuries, above note 71, pp. 177–179, 183–185.

97 For example, see VCLT, Art. 26. See also ICJ, Nuclear Tests, above note 77, para. 46 (“the very rule of pacta sunt servanda in the law of treaties is based on good faith”); ICJ, Questions Relating to the Seizure and Detention of Certain Documents and Data (Timor-Leste v. Australia), Request for the Indication of Provisional Measures, [2014] ICJ Rep. 147, 3 March 2014, para. 44 (“Once a State has made a commitment concerning its conduct, its good faith in complying with that commitment is to be presumed”); J. F. O'Connor, above note 75; John B. Whitton, “La règle ‘pacta sunt servanda’”, Recueil des Cours, Vol. 49, 1934, pp. 151–216.

98 The UN General Assembly's Friendly Relations Declaration (UNGA Res. 2625 (XXV), above note 88), for example, affirms that good faith applies to all international obligations. In Nuclear Tests (above note 77), the ICJ explained that GF governs legal obligations “whatever their source” (para. 46) and then grounded the binding effect of unilateral obligations on GF (para. 49). See, further, Lauterpacht, Hersch, “The Nature of International Law and General Jurisprudence”, Economica, Vol. 37, 1932, p. 315Google Scholar.

99 B. Cheng, above note 74, pp. 105–162; G. Futhazar and A. Peters, above note 77, p. 195.

100 For that, see DARIO, above note 11, mainly Chap. V; ILC, Draft Articles on the Responsibility of States for Internationally Wrongful Acts, 2001 (ARSIWA), mainly Chap. V. Good faith has not yet been recognized as a jus cogens norm the wrongfulness of whose violation cannot be precluded: see Article 26 of both DARIO and ARSIWA. The view that it is a jus cogens norm has been put forward by Robert Kolb, Peremptory International Law – Jus Cogens: A General Inventory, Hart, Oxford, 2015, pp. 56–58.

101 ICJ, WHO/Egypt, above note 81, paras 43, 48–49. See also ICJ, Difference Relating to Immunity from Legal Process of a Special Rapporteur of the Commission on Human Rights, Advisory Opinion, [1999] ICJ Rep. 62, 29 April 1999, pp. 109–110 (Separate Opinion of Judge Rezek). See also R. Kolb, above note 74, pp. 162–163.

102 It can be argued that the use of privileges and immunities, as discussed earlier, is one way of achieving this purpose. The broader question is whether, in the absence of a specific agreement or customary law, GF can justify the granting of privileges and immunities or justify extending them if they have already been provided. In relation to host States, see R. Higgins, above note 35, pp. 90–91 (but for a more cautious approach, see C. F. Amerasinghe, above note 12, p. 347).

103 DARIO, above note 11, Art. 52.

104 “US Diplomats Spied on UN Leadership”, The Guardian, 28 November 2010, available at: www.theguardian.com/world/2010/nov/28/us-embassy-cables-spying-un.

105 “Netherlands Defence Intelligence and Security Service disrupts Russian Cyber Operation”, above note 5.

106 DARIO, above note 11, Art. 52; see also Arts 51–54.

107 Permanent Court of Arbitration, The Chagos Marine Protected Area Arbitration (Mauritius v. U.K.), Award of 18 March 2015, paras 519, 534.

108 Ibid., paras 530–535.

109 ICJ, Voting Procedure on Questions relating to Reports and Petitions concerning the Territory of South West Africa, Advisory Opinion, [1955] ICJ Rep. 76, 7 June 1955, pp. 118–119 (Separate Opinion of Judge Lauterpacht).

110 See UN Charter, Arts 100, 101.

111 ICJ, Conditions of Admission of a State to Membership in the United Nations, Advisory Opinion, [1948] ICJ Rep. 57, 28 May 1948, pp. 62–63. See also ibid., Dissenting Opinion of Judges Basdevant, Winiarski, Sir Arnold McNair and Read, paras 20, 83, 91, and Individual Opinion of Judge Alvarez, p. 71; World Trade Organization, Shrimp Products, above note 80, para. 158; B. Cheng, above note 74, p. 121; Alexandre Kiss, “Abuse of Rights”, Max Planck Encyclopedia of International Law, 2006.

112 See, for example, Switzerland, Position Paper on the Application of International Law in Cyberspace: Annex UN GGE 2019/2021, 2021; Germany, Position Paper on the Application of International Law in Cyberspace, 2021; New Zealand, The Application of International Law to State Activity in Cyberspace, 1 December 2020; Finland, International Law and Cyberspace: Finland's National Position, 2020; French Ministry of the Armed Forces, Droit international appliqué aux opérations dans le cyberespace, 2019. For the views of MSs of the Organization of American States, see Organization of American States, Improving Transparency: International Law and State Cyber Operations (Fourth Report), OEA/Ser.Q, CJI/doc. 603/20 rev.1, 5 March 2020, pp. 18–20; Organization of American States, Binding and Non-Binding Agreements: Final Report, OEA/Ser.Q, CJI/doc. 615/20 rev.1, 7 August 2020, pp. 28–32. See, generally, Tallinn Manual 2.0, above note 21, Rules 1–4; Nicholas Tsagourias, “The Legal Status of Cyberspace: Sovereignty Redux?”, in N. Tsagourias and R. Buchan (eds), above note 10. Contra Jeremy Wright, “Cyber and International Law in the 21st Century”, 23 May 2018, available at: www.gov.uk/government/speeches/cyber-and-international-law-in-the-21st-century.

113 Permanent Court of Arbitration, Island of Palmas, 2 RIAA, 4 April 1928, p. 829.

114 See, for example, the cyber security statements listed in above note 112. See also Tallinn Manual 2.0, above note 21, Rule 1.

115 Contrast, for example, the position of Finland with that of France (see above note 112). See also Tallinn Manual 2.0, above note 21, Rule 4 and accompanying commentary. For a review of this State practice, see R. Buchan and I. Navarrete, above note 10.

116 For support for this approach, see R. Buchan, above note 10, Chap. 3; Heller, Kevin Jon, “In Defense of Pure Sovereignty in Cyberspace”, International Law Studies, Vol. 97, 2021Google Scholar.

117 See, for example, Sulmasy, Glenn and Yoo, John, “Counterintuitive: Intelligence Operations and International Law”, Michigan Journal of International Law, Vol. 28, No. 3, 2006, p. 625Google Scholar.

118 Navarrete, Iñaki and Buchan, Russell, “Out of the Legal Wilderness: Peacetime Espionage, International Law and the Existence of Customary Exceptions”, Cornell International Law Journal, Vol. 51, No. 4, 2009, p. 897Google Scholar.

119 “How the Dutch Foiled Russian ‘Cyber-Attack’ on OPCW”, BBC News, 4 October 2018, available at: www.bbc.co.uk/news/world-europe-45747472.

120 “Netherlands Defence Intelligence and Security Service Disrupts Russian Cyber Operation”, above note 5.

121 Remarks by the Minister of Defense, The Hague, 4 October 2018, available at: www.justice.gov/opa/page/file/1098576/download.

122 See “Netherlands Defence Intelligence and Security Service Disrupts Russian Cyber Operation”, above note 5: “The Netherlands shares the concerns of other international partners regarding the damaging and undermining [nature of] the GRU's [Russian military intelligence] actions. It supports the conclusion, presented today by the UK, that GRU cyber operations such as this one undermine the international rule of law.”

123 Convention on the Prohibition of the Development, Production, Stockpiling and Use of Chemical Weapons and on Their Destruction, 1993, Art. VIII(E), available at: www.opcw.org/chemical-weapons-convention/articles/article-viii-organization.

124 For a list of these agreements, see: www.opcw.org/resources/opcw-agreements.

125 ICJ, Nicaragua, above note 50, para. 251.

126 The Netherlands, “Letter to the Parliament on the International Legal Order in Cyberspace: Appendix: International Law in Cyberspace”, 5 July 2019, pp. 2–3, available at: www.government.nl/ministries/ministry-of-foreign-affairs/documents/parliamentary-documents/2019/09/26/letter-to-the-parliament-on-the-international-legal-order-in-cyberspace.

127 Switzerland, above note 112, pp. 2–3.