XmlLicenseTransform Class

Definition

Namespace:

System.Security.Cryptography.Xml

Assembly:

System.Security.Cryptography.Xml.dll

Source:

XmlLicenseTransform.cs

Represents the license transform algorithm used to normalize XrML licenses for signatures.

C#

public class XmlLicenseTransform : System.Security.Cryptography.Xml.Transform

Inheritance

Object

Transform

XmlLicenseTransform

Examples

The following code example shows how to validate an XML digital signature using the IRelDecryptor interface and the XmlLicenseTransform class.

C#

public static void CheckSignatureWithEncryptedGrant(string fileName, IRelDecryptor decryptor)
{
    // Create a new XML document.
    XmlDocument xmlDocument = new XmlDocument();
    XmlNamespaceManager nsManager = new XmlNamespaceManager(xmlDocument.NameTable);

    // Format using white spaces.
    xmlDocument.PreserveWhitespace = true;

    // Load the passed XML file into the document.
    xmlDocument.Load(fileName);
    nsManager.AddNamespace("dsig", SignedXml.XmlDsigNamespaceUrl);

    // Find the "Signature" node and create a new XmlNodeList object.
    XmlNodeList nodeList = xmlDocument.SelectNodes("//dsig:Signature", nsManager);

    for (int i = 0, count = nodeList.Count; i < count; i++)
    {
        XmlDocument clone = xmlDocument.Clone() as XmlDocument;
        XmlNodeList signatures = clone.SelectNodes("//dsig:Signature", nsManager);

        // Create a new SignedXml object and pass into it the XML document clone.
        SignedXml signedXml = new SignedXml(clone);

        // Load the signature node.
        signedXml.LoadXml((XmlElement)signatures[i]);

        // Set the context for license transform
        Transform trans = ((Reference)signedXml.SignedInfo.References[0]).TransformChain[0];

        if (trans is XmlLicenseTransform)
        {

            // Decryptor is used to decrypt encryptedGrant elements.
            if (decryptor != null)
                (trans as XmlLicenseTransform).Decryptor = decryptor;
        }

        // Check the signature and display the result.
        bool result = signedXml.CheckSignature();

        if (result)
            Console.WriteLine("SUCCESS: CheckSignatureWithEncryptedGrant - issuer index #" +
                                            i.ToString());
        else
            Console.WriteLine("FAILURE: CheckSignatureWithEncryptedGrant - issuer index #" +
                                            i.ToString());
    }
}

Remarks

The XmlLicenseTransform class represents the license transform algorithm as defined in the MPEG Rights Extension Language (MPEG REL).

Use the XmlLicenseTransform class to transform XrML licenses for signatures.

The Uniform Resource Identifier (URI) that describes the XmlLicenseTransform class is defined by the XmlLicenseTransformUrl field.

Constructors

XmlLicenseTransform()

Initializes a new instance of the XmlLicenseTransform class.

Properties

Algorithm	Gets or sets the Uniform Resource Identifier (URI) that identifies the algorithm performed by the current transform. (Inherited from Transform)
Context	Gets or sets an XmlElement object that represents the document context under which the current Transform object is running. (Inherited from Transform)
Decryptor	Gets or sets the decryptor of the current XmlLicenseTransform object.
InputTypes	Gets an array of types that are valid inputs to the OutputTypes method of the current XmlLicenseTransform object.
OutputTypes	Gets an array of types that are valid outputs from the OutputTypes method of the current XmlLicenseTransform object.
PropagatedNamespaces	Gets or sets a Hashtable object that contains the namespaces that are propagated into the signature. (Inherited from Transform)
Resolver	Sets the current XmlResolver object. (Inherited from Transform)

Methods

GetDigestedOutput(HashAlgorithm)	When overridden in a derived class, returns the digest associated with a Transform object. (Inherited from Transform)
GetInnerXml()	Returns an XML representation of the parameters of an XmlLicenseTransform object that are suitable to be included as subelements of an XMLDSIG <Transform> element.
GetOutput()	Returns the output of an XmlLicenseTransform object.
GetOutput(Type)	Returns the output of an XmlLicenseTransform object.
GetXml()	Returns the XML representation of the current Transform object. (Inherited from Transform)
LoadInnerXml(XmlNodeList)	Parses the specified XmlNodeList object as transform-specific content of a <Transform> element; this method is not supported because the XmlLicenseTransform object has no inner XML elements.
LoadInput(Object)	Loads the specified input into the current XmlLicenseTransform object.

Applies to