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Revoking Packaged Files
Content owners have the ability to revoke licenses for their own packaged Windows Media files (thereby revoking the content), if the WMRMLicGen.BindToPubKey method was used when generating these licenses.
Content revocation can be initiated only by the content owner, who generates a string based on their public and private signing keys . The license issuer includes the string in all licenses from that point forward.
You can include a content revocation string in any license. Whenever a consumer's player opens a license containing the string, licenses for all packaged files by the content owner in question are revoked and consumers can no longer play the files. If a consumer tries to play one of the revoked packaged files, the license acquisition URL opens because the license is rendered invalid. The content owner and license issuer are then responsible for providing information for consumers about the content revocation, (for example, help them get new versions of the revoked content). Unlike application revocation, which is managed by Microsoft, content revocation is a process that is completely managed by a content owner and anyone with whom they have a business relationship.
To revoke content, the content owner uses the WMRMTools.GenerateContentRevocation method to generate the content revocation string to include in licenses. This XML string is based on the content owner's signing keys, so licenses for packaged files signed with this key pair will be revoked. Then, the content owner sends this string to the license issuer (for example, in an e-mail message or on a floppy disk). The license issuer uses the WMRMLicGen.AddContentRevocation method to add this string to licenses. Later, a new pair of public and private signing keys should be generated by using the WMRMKeys.GenerateSigningKeys method and the content owner should repackage the content.
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