Recital (26)

Any processing of personal data must be lawful, fair and transparent in relation to the natural persons concerned, and only processed for specific purposes laid down by law. This does not in itself prevent the law-enforcement authorities from carrying out activities such as covert investigations or video surveillance. Such activities can be done for the purposes of the prevention, investigation, detection or prosecution of criminal offences or the execution of criminal penalties, including the safeguarding against and the prevention of threats to public security, as long as they are laid down by law and constitute a necessary and proportionate measure in a democratic society with due regard for the legitimate interests of the natural person concerned. The data protection principle of fair processing is a distinct notion from the right to a fair trial as defined in Article 47 of the Charter and in Article 6 of the European Convention for the Protection of Human Rights and Fundamental Freedoms (ECHR). Natural persons should be made aware of risks, rules, safeguards and rights in relation to the processing of their personal data and how to exercise their rights in relation to the processing. In particular, the specific purposes for which the personal data are processed should be explicit and legitimate and determined at the time of the collection of the personal data. The personal data should be adequate and relevant for the purposes for which they are processed. It should, in particular, be ensured that the personal data collected are not excessive and not kept longer than is necessary for the purpose for which they are processed. Personal data should be processed only if the purpose of the processing could not reasonably be fulfilled by other means. In order to ensure that the data are not kept longer than necessary, time limits should be established by the controller for erasure or for a periodic review. Member States should lay down appropriate safeguards for personal data stored for longer periods for archiving in the public interest, scientific, statistical or historical use.