Box 13.3 Rights Management Technologies Rights management technologies fall into two generic categories: technologies to prevent (or increase the difficulty of) an unauthorized use of an information object (e.g., an image, an audio file, a book, a movie), and technologies to facilitate after-the-fact detection of unauthorized use. Technologies intended to prevent (or increase the difficulty of) an unauthorized use of an information object (prevention technologies) generally rely on encryption techniques. For practical purposes, an encrypted information object bears no resemblance to the original, useful, unencrypted information object. Thus, such technologies rely on the authorized source of the object distributing the encrypted information object to anyone who wants it, but restricting the decryption key (without which the encrypted object is useless) to authorized parties only. Once the encrypted object is decrypted, it is usable--and if special precautions are not taken, the receiver can distribute it freely. Thus, prevention technologies rely on decrypting the object as close as possible to the point of use, and/or restricting the ability of the user to copy, e-mail, forward, or print the decrypted object. For example, an image viewer might allow the display of an image but disable the functionality of the operating system to copy that displayed image to temporary files. Technologies to facilitate after-the-fact detection of unauthorized use (detection technologies) embed into the unencrypted information object additional information that allows its creator to be identified. An example of such a technology is a digital watermark--a digital pattern that is inserted into an image that does not alter its quality but is also not easy to remove. Such transparent watermarks have obvious advantages from the standpoint of providing images that lack visible copyright markings and are as visually attractive as possible. More discussion of these technologies can be found in the CSTB report, The Digital Dilemma.1 1 Computer Science and Telecommunications Board, National Research Council, 2000, The Digital Dilemma: Intellectual Property in the Digital Age.