FIELD: stenography, implantation and detection of data on water-mark in flow of data, such as flow of videodata. SUBSTANCE: criterion of texture measures changes of selected characteristics related to each element in flow of data, type of brightness and chromaticity. Only those blocks which are found beforehand to be possessing certain degree of change of selected characteristic are selected for implantation of water-mark. Detector of water-mark in selector of blocks which evaluates same criterion of texture that was used in device for implantation of water-marks is employed in this procedure, detector makes attempt to detect water-mark only in those blocks which were found in advance to be possessing certain degree of change of selected characteristic or greater degree. Number of detection computations diminishes owing to attempt of detection of water-mark only in such blocks and ratio of signal of water-mark to noise of flow of data increases facilitating by that detection of even pour water-marks. EFFECT: reduced time and number of computations required for processing of given number of blocks. 22 cl, 3 dwg
