Article 28
1. All necessary administrative measures to maintain security shall be taken: (a) by the competent authorities of the Member States in respect of the terminals of the Customs Information System in their respective Member States and by Europol and Eurojust; (b) by the Committee referred to in Article 27 in respect of the Customs Information System and the terminals located on the same premises as the System and used for technical purposes and the checks required by paragraph 3 of this Article. 2. In particular the competent authorities, Europol, Eurojust and the Committee referred to in Article 27 shall take measures: (a) to prevent any unauthorised person from having access to installations used for the processing of data; (b) to prevent data and data media from being read, copied, modified or removed by unauthorised persons; (c) to prevent the unauthorised entry of data and any unauthorised consultation, modification or erasure of data; (d) to prevent data in the Customs Information System from being accessed by unauthorised persons by means of data transmission equipment; (e) to guarantee that, with respect to the use of the Customs Information System, authorised persons have right of access only to data for which they have competence; (f) to guarantee that it is possible to check and establish to which authorities data may be transmitted by data-transmission equipment; (g) to guarantee that it is possible to check and establish a posteriori what data have been entered in the Customs Information System, when and by whom, and to monitor searches; (h) to prevent the unauthorised reading, copying, modification or erasure of data during the transmission of data and the transport of data media. 3. The Committee referred to in Article 27 shall monitor queries of the Customs Information System for the purpose of checking that searches made were admissible and were made by authorised users. At least 1 % of all searches made shall be checked. A record of such searches and checks shall be maintained in the System and shall be used only for the abovementioned purpose by that Committee and the supervisory authorities referred to in Articles 24 and 25. It shall be erased after six months.