Data is generated which can prevent content displayed on a screen from being accurately replicated. A data-generating device has: an acquiring means that acquires still image data; a still image data generating means that generates a predetermined number of items of still image data in which at least part of pixel values of the acquired still image data are changed, and that makes an average of pixel values of matching display positions between the predetermined number of items of still image data equal to pixel values of matching display positions in the acquired still image data; and a movie data generating means that generates movie data for which each of the generated still image data is displayed at a predetermined frame rate.