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WMRMHeader Object

The WMRMHeader object manipulates content headers. If you are packaging multimedia content into a Windows Media file, you must use this object to create a content header. A content header consists of the following information:

  • The key ID used to create a key.
  • A content ID to uniquely identify the encrypted content.
  • Attributes that identify the content.
  • A URL identifying the Internet address of the license issuer.
  • The minimum application security version number required to play the Windows Media file.

The content header contains only the key ID, not the key. To re-create the key and package it in a license, a license issuer needs both the key ID and the shared license key seed.

The content ID is optional but highly recommended. For example, assume that you have multiple pieces of content and that, for a specific content, you want to delineate different rights for different consumer groups. You can do this by associating each group of rights with a different key ID, all of which are associated with a single content ID.

Attributes are name-value pairs that can be used to identify the content. For example, attributes can identify the name of the content packager, the name of the artist, and so on.

The WMRMHeader object exposes the following properties and methods.

Property Description
Attribute Specifies and retrieves name-value pairs.
ContentID Specifies and retrieves the ID of the encrypted content.
Header Specifies and retrieves the content header.
IndividualizedVersion Specifies and retrieves the minimum version of the Windows Media Rights Manager dynamic link library (DLL) that is individualized for a specific computer.
KeyID Specifies and retrieves the ID of the encryption key.
LicenseAcqURL Specifies and retrieves the URL of the Web page that the client must use to apply for a license.
Version Retrieves the version number from the content header.
Method Description
AddUplink Adds a key ID to the content header, indicating the root element in the content's license chain.
RemoveUplink Removes a key ID for a root license chain element from the content header.
SetCheckSum Specifies the checksum used for key verification.
Sign Adds a signature to the content header.
Verify Verifies the signature in the data section of the content header.

See Also