A legítima defesa contra um ciberataque

  • Beatriz Alves Serrão (Student)

Student thesis: Master's Thesis


In regard to International Law, the emerging area of cyberspace is currently one of the most trending topics, especially concerning the use of force in self-defence when a cyberattack occurs. Consequently, this dissertation will abide, in structural terms, by the requirements of the right of self-defence against a cyberattack. Firstly, the conditions under which a cyberattack may be considered an armed attack must be analysed for the purposes of article 51 of the UN Charter; as well as the following types of a lawful self-defence in the aforementioned context. After that, distinguishing a cyber-operation from a cyberattack, and its respective imputation to a State will allow to highlight the main cyberattack qualification issues. The second chapter scrutinizes how self-defence can be an acceptable (and lawful) response to a cyberattack. For this purpose, in a first stage, the material criteria (or requirements) of self-defence as a response to a cyberattack are analysed; and, in a second stage, concerning the nature of self-defence as a response to a cyberattack, the same logic is applied. Finally, international organizations work regarding cyber self-defence will be highlighted, mainly due to its contribution to broader debates within international law. In sum, this dissertation allowed the following conclusion: international law does not establish a specific cyber-operation legal framework; thus, there is a need to resort to traditional international law norms. Last but not least, this research also allowed to understand that, even though it is very hard to check all the requirements of a lawful self-defence in a cyber context, cyber self-defence is acceptable and lawful as a proportional response to a cyberattack.
Date of Award29 Jul 2021
Original languagePortuguese
Awarding Institution
  • Universidade Católica Portuguesa
SupervisorMaria Isabel Tavares (Supervisor)


  • Cyber self-defence
  • Cyberattack
  • Cyber-operation


  • Mestrado em Direito

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