Abstract. As the amount of digitalized contents increases rapidly, ‘security’ necessarily arises as one of the most important issues. The main distribution channel of digital contents is Internet which is very easily accessible. Therefore content protection becomes a major issue as important as data coding techniques. In recent years, many developers have studied techniques that allow only authorized person to access contents. Among them, scrambling is one of well-known security techniques. In this paper, we propose a simple and effective digital video scrambling method which utilizes the intra block properties of a recent video coding technique, H.264. In addition to its simplicity, the proposed method does not cause bit rate increase after scrambling.