In the current historical context characterized by the technology of information and by a massive spread of digitalization in various fields, new forms of terrorism threaten the security of the States which, in most cases, are unprepared to stem the catastrophic consequences of terrorism, both of traditional type and, so to say, computer type. The States, therefore, have to face new types of threat to their national security; with respect to these threats the traditional defensive measures revealed themselves totally inadequate. Threats like these need multilateral responses and a more focused effort at the level of international cooperation. However, technological development has been used and is used also by the States which, through the use of spy software (computer virus) installed in cell phones, are able to monitor electronic communications, and to acquire remotely, in addition to the content of the communications also all the data in the respective cloud of pertinence of the phone users or of the PC in question. This study aims to analyse the Italian, European and international legislation (if 60 any) in the field of interceptions by spy software and to carry out a comparative analysis of existing legislation in different States of the international Community in order to identify possible solutions in regard to the balance of conflicting demands of protection: on the one hand, the safety of citizens and, on the other hand, the secrecy of communications.