KDM is the acronym for Key Delivery Message. A KDM is required to play an encrypted movie. Each KDM allows one version of a movie to be played on the targeted digital cinema server or media block during a specified time period. The KDM carries security credentials for the movie in encrypted form, which can only be decrypted by the target device. Thus, a KDM delivered to the wrong server or wrong location cannot be decrypted and will not work, nor will such an error compromise the security of the movie.
The KDM is a small file, that, in legacy systems, is typically emailed to the exhibitor. Automated key delivery using the Facility List Message is now available.
