Windows Media DRM License Acquisition

Windows Media DRM works by encrypting content and then requiring end users to get a license to decrypt that content. In this illustration, the content distributor is a Web site selling music downloads. To play these downloads, the end user must retrieve a license. Although content distributors may offer licenses themselves, they often use a license clearinghouse, which specializes in license distribution and related tasks, such as securing usage rights from content owners. (One clearinghouse can handle license distribution for multiple content distributors.)

The process works as follows:

(1) Based on specifications set by the content owner, the online music store applies Windows Media DRM to the content. To apply the DRM, the store can use Microsoft’s Rights Manager SDK, Windows Media Encoder, or a tool or service from a Windows Media DRM partner such as DMDSecure. The content is encrypted with a key that’s created by hashing a license key seed, a secret value that is shared between the music store and the license clearinghouse and applies to all content, and a license key ID, a value that is generated by the music store during the protection process and is specific to that individual piece of content.