Microsoft KB Archive/867664

= You experience slow performance while signing DRM files in the Windows Media Rights Manager SDK =

Article ID: 867664

Article Last Modified on 7/28/2004

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APPLIES TO


 * Microsoft Windows Media Rights Manager 9 Series

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SYMPTOMS
When you try to reheader multiple Digital Rights Management (DRM) files by using the Microsoft Windows Media Rights Manager Software Development Kit (SDK), you may notice that it takes a long time to sign these files.



RESOLUTION
A new method has been added to the Windows Media Rights Manager SDK to permit in-memory signing of DRM files. For more information about how to use this new method, see the Windows Media Rights Manager SDK documentation.



IWMRMHeaderSigning interface
The IWMRMHeaderSigning interface lets you sign content headers in memory. This interface is not Automation-compliant. Besides the methods that are inherited from the IUnknown interface, the IWMRMHeaderSigning interface implements the IWMRMTools interface and exposes the following method.

AddDigitalSignatureObject: Signs the ASF content header in memory.

IWMRMHeaderSigning::AddDigitalSignatureObject
The AddDigitalSignatureObject method signs the ASF content header of protected content in memory.

Syntax
HRESULT AddDigitalSignatureObject( BYTE *pbHeader,  DWORD dwSize,  DWORD *pdwBytesNeeded );

Parameters
pbHeader: [in, out] Pointer to a buffer that contains a valid content header. The content header with an ASF Digital Signature object is returned.

dwSize: [in] Size of the pbHeader buffer, in bytes.

pdwBytesNeeded: [out] If the dwSize parameter is too small, a value is returned that indicates how many more bytes are needed.

Return Values
If the method succeeds, it returns S_OK and the signed content header. If the method fails, it returns an HRESULT error code. If the dwSize parameter is not large enough, the error NS_E_DRM_BUFFER_TOO_SMALL is returned, and the pdwBytesNeeded parameter indicates how many more bytes are needed.

Remarks
The content header must be valid. That is, the header must have an ASF Data object. The Data object can be empty. If the content already contains a Digital Signature object, this method will replace it with a new one. This method is similar to the Digsig.exe command-line tool. The Digsig.exe command-line tool digitally signs a file on disk, and this method digitally signs content in memory.

Additional query words: WMRM

Keywords: kbfix KB867664

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