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WMRMChallenge.ClientAttribute

The ClientAttribute property retrieves a specific attribute, by name, from the client information section of a challenge.

Syntax

String = WMRMChallenge.ClientAttribute(bstrName)

Parameters

bstrName

[in] String containing the name of the attribute to be retrieved.

Return Values

If the property succeeds, it returns a String containing the attribute. If it fails, it returns a number in the error object.

Return code Description
0x80004005 An unspecified error occurred.
0x80070057 The specified parameter is not valid.

Remarks

This property is read-only. The ClientAttribute property does not retrieve the encrypted client ID. Only the following attribute names are valid.

Note   These values are not signed and should be used for information only, not for security purposes.

Attribute name Description
CLIENTVERSION Identifies the version of the DRM component on the client computer.
SECURITYVERSION Identifies the DRM component version in the format a.b.c.d, where a.b is the version, c is reserved, and d is the category.
APPSECURITY Identifies the minimum security level that the application must have to play a packaged file.
SUBJECTID1 Identifies the Windows Media Format SDK on which the application is based.
SUBJECTID2 Identifies the application.
DRMKVERSION Identifies the version number of the secure audio path (SAP) kernel component.

This property requires you to retrieve specific values and check them. However, in some situations, the new WMRMChallenge.CheckClientCapability method may be more useful because it checks for specific functionality, returning True or False.

Example Code

' Assume that the content packager has sent encrypted content and 
' a header to a consumer. The consumer's computer determines that 
' a license is needed and posts a challenge to the license issuer.
' The challenge contains the header sent by the content packager,
' actions requested by the client, and information about the client
' computer.
'
' For more information about the header, see the WMRMHeader object.


' Declare variables and objects.

    Dim sHeader, sClientInfo, sPubKey, lResult, dwActionCnt
    Dim sLicRequest, lIndex, sVerClient, sVerSecurity, sAppSecurity
    Dim sAction()
    Dim HeaderObj
    Dim ChallengeObj

' Create objects.

    Set HeaderObj = Server.CreateObject("Wmrmobjs.WMRMHeader")
    Set ChallengeObj = Server.CreateObject("Wmrmobjs.WMRMChallenge")
  
' Retrieve the license request from the client computer.

    sLicRequest = request.Form("challenge")

' Set the license request into the WMRMChallenge object.

    ChallengeObj.Challenge = sLicRequest

' Retrieve the header from the challenge.

    sHeader = ChallengeObj.Header

' Set the header into the WMRMHeader object.

    HeaderObj.Header = sHeader

' Verify the header with the public key created by the content
' packager.

    lResult = HeaderObj.Verify(sPubKey)
    if (lResult = 0) then
        ' The header has been corrupted.
    end if

' Retrieve the client information section of the challenge.

    sClientInfo = ChallengeObj.ClientInfo

' Retrieve attributes from the client.

    sVerClient = ChallengeObj.ClientAttribute("CLIENTVERSION" )
        ' Perform actions based on the DRM component
        ' version installed on the client computer.

    sVerSecurity = ChallengeObj.ClientAttribute("SECURITYVERSION")
        ' Perform actions based on the security version number.

    sAppSecurity  = ChallengeObj.ClientAttribute("APPSECURITY")
        ' Perform actions based on the security level of the 
        ' application on which the Windows Media file is to
        ' be played.

Requirements

Version: Windows Media Rights Manager 7 SDK or later

Reference: wmrmobjs 1.0 Type Library

Library: wmrmobjs.dll

Platform: Windows Server 2003

See Also