Methods and systems for protecting data that is intended for use and
processed on video or graphics cards are described. In various
embodiments, data that is intended for use by a video card can be
encrypted such that any time the data is provided onto a bus (e.g. a PCI
or AGP bus) between the video card and the computer system, the data is
encrypted. For example, when data is moved from memory on the video card
to the system's memory (e.g. when it is mapped to the system's physical
memory) and vice versa, the data is in encrypted form and thus protected.