data. Furthermore, the European Union established clear basic principles for the collection, storage and use of personal data by governments, businesses and other organizations or individuals in Directive 95/46/EC and Directive 2002/58/EC on Privacy and Electronic communications. Nonetheless, the twenty-?rst century citizen - utilizing the full potential of what ICT-technology has to offer - seems to develop a digital persona that becomes increasingly part of his individual social identity. From this perspective, control over personal information is control over an aspect of the identity one projects in the world. The right to privacy is the freedom from unreasonable constraints on one's own identity. Transactiondata-bothtraf?candlocationdata-deserveourparticularattention. As we make phone calls, send e-mails or SMS messages, data trails are generated within public networks that we use for these communications. While traf?c data are necessary for the provision of communication services, they are also very sensitive data. They can give a complete picture of a person's contacts, habits, interests, act- ities and whereabouts. Location data, especially if very precise, can be used for the provision of services such as route guidance, location of stolen or missing property, tourist information, etc. In case of emergency, they can be helpful in dispatching assistance and rescue teams to the location of a person in distress. However, p- cessing location data in mobile communication networks also creates the possibility of permanent surveillance.