How are security keys (KDM) delivered?
Monday, 25 September 2006 15:56
Security keys are delivered per movie per server. In other words, it takes a unique security key to play a particular movie title on a particular server. Keys are delivered in a text-based XML message called a KDM, the acronym for Key Delivery Message. The KDM contains the key or keys required to unlock encrypted content. The content key itself is encrypted so that it's not exposed by simply viewing the contents of the XML file. The KDM is a small file, and is often emailed or delivered by means of disc or USB thumb drive without any loss of security. (DCI's spec, however, asks that it be delivered over telephone modem.)