The Ph.D. project aimed to analyze the right to privacy in light of the recent restrictions and derogations put in place in international and European law, particularly in response to the terrorist attacks that occurred on 11th September, 2001. In this context, tensions peaked in 2013 when former NSA employee, Edward Snowden, denounced mass surveillance programs put in place by the American government. These programs, made also possible by the collaboration of the most important American internet service providers, aimed to monitor American citizens and not. Undeniably, in 2013 the international community gained greater awareness of the potential risks connected to the indiscriminate collection of personal information by the National Security and law enforcement authorities. In fact, there are still many States that consider mass surveillance an effective tool in protecting national security and preventing terrorist attacks. However, these measures simultaneously contain considerable risks for citizens' rights, due to either the frequent lack of adequate jurisdictional control at a national level or the indiscriminate nature of the data collected. Despite the importance of the right to privacy, there is still a lack of adequate legislation in this matter. This is especially evident at the international level. Notably, Article 12 of the Universal Declaration of Human Rights and Article 17 of the International Covenant on Civil and Political Rights both fail to explicitly provide for the protection of personal data. Furthermore, there is no mention of this right in article 8 ECHR. The legal deficiencies, mainly caused by the lack of adequate technical knowledge on the matter during the period that these conventions were drafted and ratified, have been partially compensated for by the development in case-law put in place by the European Court of Human Rights, beginning with the Klass and others v. Germany sentence until the more recent Big Brother Watch and others v. United Kingdom. In particular, according to the judges of Strasbourg, any limitation must be provided for by law, pursuing a legitimate aim, is necessary in a democratic society and respectful of the principle of proportionality. From a legislative point of view, the situation seems to be consistently more favorable in the European context where the right to privacy has become a fundamental right, according to Article 8 of the Charter of Fundamental Rights of the European Union and Article 16 TFEU. In the final part of the project have been also identified and analyzed other significant unresolved issues in the context of the right to privacy, regarding in particular corporate responsibility for illegitimate transmission of personal data to National Security and law enforcement authorities, which violates international standards protecting human rights, and possible extraterritorial exercise of jurisdiction by monitoring bodies.