A hardware functionality scan (HFS) is conducted in order to verify that a certain device is really what it claims to be. It is patented by

Microsoft Microsoft Corporation is an American multinational corporation and technology company, technology conglomerate headquartered in Redmond, Washington. Founded in 1975, the company became influential in the History of personal computers#The ear ...

. Some

operating system An operating system (OS) is system software that manages computer hardware and software resources, and provides common daemon (computing), services for computer programs. Time-sharing operating systems scheduler (computing), schedule tasks for ...

s only send copy protected content, such as

movies A film, also known as a movie or motion picture, is a work of visual art that simulates experiences and otherwise communicates ideas, stories, perceptions, emotions, or atmosphere through the use of moving images that are generally, since ...

, to an output device, such as the screen, if that device is able to protect the content from being tapped in an unprotected format. This mechanism can be circumvented by letting fake hardware claiming to be a trusted device. HFS prevents this by letting the device perform certain tasks which are hard to emulate.

Problems

In order to support open-source drivers, a hardware manufacturer has to reveal some details about their product, but HFS requires this information to be kept secret. The problem with generic drivers is that the HFS requires individual drivers for each variant of a product to make them distinguishable, drivers have to account for implementation details instead of using abstract functionality models. A hardware manufacturer has to have their product's HFS fingerprint listed in the database of trusted hardware in order to make it work under newer Windows operating systems. Thus, Microsoft dictates the conditions under which a device is accepted. The manufacturer may be required to implement certain

DRM DRM may refer to: Government, military and politics * Defense reform movement, U.S. campaign inspired by Col. John Boyd * Democratic Republic of Madagascar, a former socialist state (1975–1992) on Madagascar * Direction du renseignement militair ...

-features, for which they have to pay a

royalty Royalty may refer to: * the mystique/prestige bestowed upon monarchs ** one or more monarchs, such as kings, queens, emperors, empresses, princes, princesses, etc. *** royal family, the immediate family of a king or queen-regnant, and sometimes h ...

to its respective

inventor An invention is a unique or novel device, method, composition, idea, or process. An invention may be an improvement upon a machine, product, or process for increasing efficiency or lowering cost. It may also be an entirely new concept. If an ...

References

Digital rights management systems Proprietary hardware {{computer-security-stub