Analog hole

The analog hole (also known as the analog loophole or analog gap) is a perceived fundamental and inevitable vulnerability in copy protection schemes for noninteractive works in digital formats which can be exploited to duplicate copy-protected works using analog means. Once digital information is converted to a human-perceptible (analog) form, it is a relatively simple matter to digitally recapture that analog reproduction in an unrestricted form, thereby fundamentally circumventing any and all restrictions placed on copyrighted digitally distributed work. Media publishers who use digital rights management (DRM), to restrict how a work can be used, perceive the necessity to make it visible or audible as a "hole" in the control that DRM otherwise affords them.

Overview

Although the technology for creating digital recordings from analog sources has existed for some time, it was not necessarily viewed as a "hole" until the widespread deployment of DRM in the late 1990s. However, if the correct equipment is not used to perform the conversion, the resulting copy may have distinguishable low fidelity (or other deformations) compared to the analog (or digital) original.

Regardless of any digital or software copy control mechanisms, if sound can be captured by a microphone, it can be either recorded by analog means (e.g. magnetic tape), or stored digitally. And if images (static images or video/film), including text, can be seen by a camera, they can also be recorded. In the case of text the image can be converted back to text using optical character recognition (OCR).

In the case of digital images, content creators may try and prevent casual copying by configuring webpages to disable the "Save image" function, but this can easily be defeated by taking a screenshot (or taking a photograph of the screen), even if this results in a loss of quality.