The method is based on symmetrical encryption algorithms of variable length blocks, supported by a Pseudo-noise Sequence Generator based in its turn in one (or two) linear sequence generators (LFSR with a primitive polynomial). The basic versions of these algorithms include the plotting of a set of lines which is defined by a pole and a contour, but ensuring that the points inside the contour became inverted when plotted each time the pixel is found in one of the set of lines. Usually, two contours will be used, one of them shall act as the boundary for the data area and in a modification of the same the set of lines is created by means of unregularised contours.