The Hungarian regulation on secret information gathering was subject of the ECtHR (Szabó and Vissy v. Hungary, no. 37138/14., 12/01/16) in which two activists of an NGO complained that they might have been subjects of secret information gathering. The decision that stipulated the infringement of Article 8 of the Convention settled essential criteria both concerning legislation and jurisdiction. The presentation first analyses the background of the case. Secondly the reasons for different argumentation of the national constitutional court and the ECtHR, thirdly how can secret information gathering be in accordance with the provisions of the Convention with special regard to the required control mechanism. The decision clarifies that counter-terrorism measures cannot entirely overrule privacy rights. Secret information gathering must be supervised by (quasi) judicial organs. As the challenges arise worldwide, all European legislators could gain useful experience from the decision.