How amazing would it be to prevent illegal copies of computer games? Game developers work with the hope that they can make good profit out of their games, but when they know that they would not sell much they will be so disappointed and that is because once a few original copies of their games are released, soon or late, there will be illegal copies available in the market. Working on how to distinguish between a legal copy and an illegal copy is the general topic of this thesis. / In a game there are many images and textures used for graphical purposes. One of the most recent texture file extensions used in modern games to store Microsoft DirectDraw Surface which is the basic image unit in Microsoft DirectX graphics is DirectDraw Surface or DDS in short. In this thesis, it was attempted to embed as many bits (watermark/ message) as possible and retrieve the bits after embedding to mark the file in a distinguishable way. The result has been very promising under different circumstances. / +46723136160