Abstract: Method and system for preventing copying of textual images during display on a screen. The method includes randomly adding bits to the bitmapped background of the textual image to produce two random bitmapped textual images. The random bitmapped images are then alternately displayed on the screen so that the instantaneous display of the on screen textual images is unreadable. By a second method, the bits that form the bitmapped image of the text bits are randomly modified to produce a pair of random bitmapped texts. The random bit mapped text pairs are then alternately flickered on the display screen. Again, by this second method, the instantaneous display of the on screen textual images is unreadable. Although in both cases the instantaneous display is unreadable, the human eye averages the two different bitmapped images as they alternate on screen so that the text is human readable.