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SignedXml.XmlDsigEnvelopedSignatureTransformUrl Field

Represents the Uniform Resource Identifier (URI) for enveloped signature transformation. This field is constant.

Namespace:  System.Security.Cryptography.Xml
Assembly:  System.Security (in System.Security.dll)

public const string XmlDsigEnvelopedSignatureTransformUrl

The value of the XmlDsigEnvelopedSignatureTransformUrl field is "http://www.w3.org/2000/09/xmldsig#enveloped-signature".

Use this field to conveniently supply a value to one of the URI attributes of an element used for XMLDSIG.

The XmlDsigEnvelopedSignatureTransform class implements the transform described by the XmlDsigEnvelopedSignatureTransformUrl field.

For more information, see the World Wide Web Consortium (W3C) specification at http://www.w3.org/2000/09/xmldsig#enveloped-signature.

The following code example demonstrates how to use members of the XmlDsigEnvelopedSignatureTransform class.

using System;
using System.IO;
using System.Xml;
using System.Security.Cryptography;
using System.Security.Cryptography.Xml;
using System.Security.Cryptography.X509Certificates;

class Class1
{
    private static string Certificate =  "..\\..\\my509.cer";

    [STAThread]
    static void Main(string[] args)
    {
        // Encrypt an XML message
        XmlDocument productsXml = LoadProducts();
        ShowTransformProperties(productsXml);

        SignDocument(ref productsXml);
        ShowTransformProperties(productsXml);

        // Use XmlDsigEnvelopedSignatureTransform to resolve a Uri.
        Uri baseUri = new Uri("http://www.contoso.com");
        string relativeUri = "xml";
        Uri absoluteUri = ResolveUris(baseUri, relativeUri);

        Console.WriteLine("This sample completed successfully; " +
            "press Enter to exit.");
        Console.ReadLine();
    }

    // Encrypt the text in the specified XmlDocument. 
    private static void ShowTransformProperties(XmlDocument xmlDoc)
    {
        XmlDsigEnvelopedSignatureTransform xmlTransform = 
            new XmlDsigEnvelopedSignatureTransform();

        // Ensure the transform is using the proper algorithm.
        xmlTransform.Algorithm =
            SignedXml.XmlDsigEnvelopedSignatureTransformUrl;

        // Retrieve the XML representation of the current transform.
        XmlElement xmlInTransform = xmlTransform.GetXml();

        Console.WriteLine("\nXml representation of the current transform: ");
        Console.WriteLine(xmlInTransform.OuterXml);

        // Retrieve the valid input types for the current transform.
        Type[] validInTypes = xmlTransform.InputTypes;

        // Verify the xmlTransform can accept the XMLDocument as an 
        // input type. 
        for (int i=0; i<validInTypes.Length; i++)
        {
            if (validInTypes[i] == xmlDoc.GetType())
            {
                // Load the document into the transfrom.
                xmlTransform.LoadInput(xmlDoc);

                bool IncludeComments = true;
                // This transform is created for demonstration purposes.
                XmlDsigEnvelopedSignatureTransform secondTransform =
                    new XmlDsigEnvelopedSignatureTransform(IncludeComments);

                string classDescription = secondTransform.ToString();

                // This call does not perform as expected. 
                // An enveloped signature has no inner XML elements
                secondTransform.LoadInnerXml(xmlDoc.SelectNodes("//."));

                break;
            }
        }

        Type[] validOutTypes = xmlTransform.OutputTypes;

        for (int i=validOutTypes.Length-1; i >= 0; i--)
        {
            if (validOutTypes[i] == typeof(System.Xml.XmlDocument))
            {
                try 
                {
                    Type xmlDocumentType = typeof(System.Xml.XmlDocument);
                    XmlDocument xmlDocumentOutput = (XmlDocument) 
                        xmlTransform.GetOutput(xmlDocumentType);

                    // Display to the console the Xml before and after 
                    // encryption.
                    Console.WriteLine("Result of the GetOutput method call" +
                        " from the current transform: " + 
                        xmlDocumentOutput.OuterXml);
                }
                catch (Exception ex)
                {
                    Console.WriteLine("Unexpected exception caught: " +
                        ex.ToString());
                }

                break;
            }
            else if (validOutTypes[i] == typeof(System.Xml.XmlNodeList))
            {
                try 
                {
                    Type xmlNodeListType = typeof(System.Xml.XmlNodeList);
                    XmlNodeList xmlNodes = (XmlNodeList) 
                        xmlTransform.GetOutput(xmlNodeListType);

                    // Display to the console the Xml before and after 
                    // encryption.
                    Console.WriteLine("Encoding the following message: " +
                        xmlDoc.InnerText);

                    Console.WriteLine("Nodes of the XmlNodeList retrieved " +
                        "from GetOutput:");
                    for (int j=0; j < xmlNodes.Count; j++)
                    {
                        Console.WriteLine("Node " + j + 
                            " has the following name: " + 
                            xmlNodes.Item(j).Name + 
                            " and the following InnerXml: " + 
                            xmlNodes.Item(j).InnerXml);
                    }
                }
                catch (Exception ex)
                {
                    Console.WriteLine("Unexpected exception caught: " +
                        ex.ToString());
                }

                break;
            }
            else
            {
                object outputObject = xmlTransform.GetOutput();
            }
        }
    }

    // Create an XML document describing various products. 
    private static XmlDocument LoadProducts()
    {
        XmlDocument xmlDoc = new XmlDocument();

        string contosoProducts = "<PRODUCTS>";
        contosoProducts += "<PRODUCT><ID>123</ID>";
        contosoProducts += "<DESCRIPTION>Router</DESCRIPTION></PRODUCT>";
        contosoProducts += "<PRODUCT><ID>456</ID>";
        contosoProducts += "<DESCRIPTION>Keyboard</DESCRIPTION></PRODUCT>";
        contosoProducts += "<PRODUCT><ID>789</ID>";
        contosoProducts += "<DESCRIPTION>Monitor</DESCRIPTION></PRODUCT>";
        contosoProducts += "</PRODUCTS>";

        xmlDoc.LoadXml(contosoProducts);
        return xmlDoc;
    }

    // Create a signature and add it to the specified document. 
    private static void SignDocument(ref XmlDocument xmlDoc)
    {
        // Generate a signing key.
        RSACryptoServiceProvider Key = new RSACryptoServiceProvider();

        // Create a SignedXml object.
        SignedXml signedXml = new SignedXml(xmlDoc);

        // Add the key to the SignedXml document. 
        signedXml.SigningKey = Key;

        // Create a reference to be signed.
        Reference reference = new Reference();
        reference.Uri = "";

        // Add an enveloped transformation to the reference.
        reference.AddTransform(new XmlDsigEnvelopedSignatureTransform());

        // Add the reference to the SignedXml object.
        signedXml.AddReference(reference);

        try 
        {
            // Create a new KeyInfo object.
            KeyInfo keyInfo = new KeyInfo();

            // Load the X509 certificate.
            X509Certificate MSCert =
                X509Certificate.CreateFromCertFile(Certificate);

            // Load the certificate into a KeyInfoX509Data object 
            // and add it to the KeyInfo object.
            keyInfo.AddClause(new KeyInfoX509Data(MSCert));

            // Add the KeyInfo object to the SignedXml object.
            signedXml.KeyInfo = keyInfo;
        }
        catch (FileNotFoundException ex)
        {
            Console.WriteLine("Unable to locate the following file: " + 
                Certificate);
        }

        // Compute the signature.
        signedXml.ComputeSignature();

        // Add the signature branch to the original tree so it is enveloped.
        xmlDoc.DocumentElement.AppendChild(signedXml.GetXml());
    }

    // Resolve the specified base and relative Uri's . 
    private static Uri ResolveUris(Uri baseUri, string relativeUri)
    {
        XmlUrlResolver xmlResolver = new XmlUrlResolver();
        xmlResolver.Credentials = 
            System.Net.CredentialCache.DefaultCredentials;

        XmlDsigEnvelopedSignatureTransform xmlTransform =
            new XmlDsigEnvelopedSignatureTransform();
        xmlTransform.Resolver = xmlResolver;

        Uri absoluteUri = xmlResolver.ResolveUri(baseUri, relativeUri);

        if (absoluteUri != null)
        {
            Console.WriteLine(
                "\nResolved the base Uri and relative Uri to the following:");
            Console.WriteLine(absoluteUri.ToString());
        }
        else
        {
            Console.WriteLine(
                "Unable to resolve the base Uri and relative Uri");
        }
        return absoluteUri;
    }
}
// 
// This sample produces the following output: 
// 
// Xml representation of the current transform:  
// <Transform Algorithm="http://www.w3.org/2000/09/xmldsig#enveloped- 
// signature" xmlns="http://www.w3.org/2000/09/xmldsig#" /> 
// Result of the GetOutput method call from the current transform: <PRODUCTS> 
// <PRODUCT><ID>123</ID><DESCRIPTION>Router</DESCRIPTION></PRODUCT><PRODUCT> 
// <ID>456</ID><DESCRIPTION>Keyboard</DESCRIPTION></PRODUCT><PRODUCT><ID>789 
// </ID><DESCRIPTION>Monitor</DESCRIPTION></PRODUCT></PRODUCTS> 
// Unable to load the following file: ..\\my509.cer 
//  
// Xml representation of the current transform:  
// <Transform Algorithm="http://www.w3.org/2000/09/xmldsig#enveloped- 
// signature" xmlns="http://www.w3.org/2000/09/xmldsig#" /> 
// Result of the GetOutput method call from the current transform: <PRODUCTS> 
// <PRODUCT><ID>123</ID><DESCRIPTION>Router</DESCRIPTION></PRODUCT><PRODUCT> 
// <ID>456</ID><DESCRIPTION>Keyboard</DESCRIPTION></PRODUCT><PRODUCT><ID>789 
// </ID><DESCRIPTION>Monitor</DESCRIPTION></PRODUCT><Signature xmlns= 
// "http://www.w3.org/2000/09/xmldsig#"><SignedInfo><CanonicalizationMethod 
// Algorithm="http://www.w3.org/TR/2001/REC-xml-c14n-20010315" />
// <SignatureMethod Algorithm="http://www.w3.org/2000/09/xmldsig#rsa-sha1" />
// <Reference URI=""><Transforms><Transform Algorithm="http://www.w3.org/2000 
// /09/xmldsig#enveloped-signature" /></Transforms><DigestMethod Algorithm= 
// "http://www.w3.org/2000/09/xmldsig#sha1" /><DigestValue>KvPW6HUiIUMEDS0YSoT
// gpo2JPbA=</DigestValue></Reference></SignedInfo><SignatureValue>c/njCGDru/a 
// WAmWG83I+mWO040xOzxvmNx0b0o8ZyPc9j5VwApdAt103OGBtB1H6EkOvt7Ekw+PVuUo8m5LzLP 
// yaTxUDMbb2kZZ5itSkGD4rmMUMUMuzrkAoquJZjxeOydBJ2CMehV2rE3RMPLIwRX176DZVy5JKU 
// 6Cb7PR2Rpw=</SignatureValue></Signature></PRODUCTS> 
//  
// Resolved the base Uri and relative Uri to the following: 
// http://www.contoso.com/xml 
// This sample completed successfully; press Enter to exit.

.NET Framework

Supported in: 4.5, 4, 3.5, 3.0, 2.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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