How do optical protection technologies work?

In many countries, so-called "anti-piracy devices", such as holograms, stickers, microscopic labels, or banderoles, have been developed, which are placed on products prior to their distribution on the market. Such devices aim at marking each legitimate copy of a work by optical means, so that they could be easily identified when offered and distinguished from fake products. Such a system enables customers to be aware of the legitimacy of a product and allows the authorities to act quickly when infringing content appears on the market. The most prevalent technology in this respect today probably is the hologram, mainly because copying is relatively costly and technically complicated.

However, if such an authentication system is not well established and controlled, there is a risk that the infringers themselves abuse the system, for example by producing and using fake devices. In order to avoid such vulnerabilities, governmental authorities frequently try to supervise the production of anti-piracy devices.