FIELD: concentrically recording data in data medium and their protection against unauthorized copying. SUBSTANCE: data medium may be, for example, CD or DVD dusk. Data file for recording is generated in the form of first sequence of data sectors, their addresses being, essentially, natural sequence; first sequence of generated sectors with respective addresses in the form of helical track is recorded; in generating first sequence of sectors at least one second sequence of data sectors is produced, its sector addresses being at least partially in coincidence with those of first sequence; number of coinciding addresses equals and constitutes at least number of data sectors entered in two adjacent turns of helical track in area corresponding to addresses of these sectors. Key data are recorded in sectors whose addresses coincide. EFFECT: enlarged functional capabilities, simplified check-up procedure, reduced cost of equipment, enhanced copy protection level. 11 cl
