The holograms found on credit cards are made up of several layers of images taken at different angles and stacked on top of one another. The image therefore appears to change when it is moved even slightly. The way the image appears on the credit card makes it appear as though it is raised above the plastic, giving it a look of depth.
Holograms prevent counterfeiting because the multiple images of a hologram cannot be scanned by an optical computer scanner or copied on a photocopier. In addition, holograms generally have hidden images placed within them to provide immediate authentication and validation.
Security holograms, originated in the early 1980s by MasterCard International, are used not only on credit cards, but on passports, expensive electronics and even banknotes.