
Silverlight DRM Conceptual Overview
The following diagram summarizes the processes needed for Silverlight to play back DRM content as well as the server/client interactions needed to facilitate those processes. Later, each of these steps is discussed in greater detail.
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1. Silverlight Client Accesses Content
The end user attempts to play some DRM protected content in a Silverlight application that is stored on the distribution server (a distribution server, usually a Web server, is used to distribute your content). The Silverlight client downloads the content (or some of the content in the case of streaming) and the header.
2. Is the Client Individualized?
Before Silverlight requests the license to decrypt the content, Silverlight must first determine whether the end user’s computer has the appropriate DRM software installed. This software is called the individualization component and is the client component of DRM that is required before any protected content can be played. The individualization component software enables the client computer to request and use a DRM License and protects sensitive data used in the decryption process.
If the appropriate individualized component software is not already on the client, the client requests the component from the Microsoft Individualization Service. The process of obtaining the individualized component software is called Individualization. Silverlight individualizes the user's computer by sending information to the Microsoft Individualization Service (note that the end user can block sending this information; see Error Handling later in this topic). Once valid individualization component is installed, the client does not need to individualize again until new versions of the individualization component are made available by Microsoft.
3. Silverlight Requests License
Once valid individualization component software exists on the client, it is ready to play DRM. Now, when a page with DRM content is visited, the Silverlight client will contact the PlayReady License Server to obtain a license (the License Server is controlled by you or your service provider). If the License Server approves the request, it issues a license which will be used by the client to decrypt the particular media file. After this, the content can be played.