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SignedXml.XmlDsigC14NTransformUrl Field

Represents the Uniform Resource Identifier (URI) for the Canonical XML transformation. This field is constant.

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

public const string XmlDsigC14NTransformUrl

The value of the XmlDsigC14NTransformUrl field is "http://www.w3.org/TR/2001/REC-xml-c14n-20010315".

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

The XmlDsigC14NTransform class implements the transform described by the XmlDsigC14NTransformUrl field.

For more information, see the World Wide Web Consortium (W3C) specification at http://www.w3.org/TR/2001/REC-xml-c14n-20010315.

This field has the same value as the XmlDsigCanonicalizationUrl field.

The following code example demonstrates how to call members of the XmlDsigC14NTransform 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 XmlDsigC14NTransform 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)
    {
        XmlDsigC14NTransform xmlTransform = 
            new XmlDsigC14NTransform(true);

        // Ensure the transform is using the appropriate algorithm.
        xmlTransform.Algorithm =
            SignedXml.XmlDsigExcC14NTransformUrl;

        // 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);

                XmlDsigC14NTransform secondTransform = 
                    new XmlDsigC14NTransform();

                string classDescription = secondTransform.ToString();

                // This call does not perform as expected.
                // This transform does not contain inner XML elements
                secondTransform.LoadInnerXml(xmlDoc.SelectNodes("//."));

                break;
            }
        }

        Type[] validOutTypes = xmlTransform.OutputTypes;

        for (int i=0; i<validOutTypes.Length;i++)
        {
            if (validOutTypes[i] == typeof(System.IO.Stream))
            {
                try 
                {
                    Type streamType = typeof(System.IO.Stream);
                    MemoryStream outputStream = (MemoryStream) 
                        xmlTransform.GetOutput(streamType);

                    // Read the CryptoStream into a stream reader.
                    StreamReader streamReader =
                        new StreamReader(outputStream);

                    // Read the stream into a string.
                    string outputMessage = streamReader.ReadToEnd();

                    // Close the streams.
                    outputStream.Close();
                    streamReader.Close();

                    // Display to the console the Xml before and after
                    // encryption.
                    Console.WriteLine("Encoding the following xml: " +
                        xmlDoc.OuterXml);
                    Console.WriteLine("Message encoded: " + outputMessage);
                }
                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>";

        // Include a comment to test the comments feature of the transform.
        contosoProducts += "<!--Comments are included in the transform-->";

        // Include the CDATA tag to test the transform results.
        contosoProducts += "<PARTNER_URL><![CDATA['http:\\\\www.contoso.com";
        contosoProducts += "\\partner.asp?h1=en&h2=cr']]></PARTNER_URL>";
        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 XmlDsigC14NTransform());

        // 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)
        {
            Console.WriteLine("Unable to locate the following file: " + 
                Certificate);
        }
        catch (CryptographicException ex)
        {
            Console.WriteLine("Unexpected exception caught whild creating " +
                "the certificate:" + ex.ToString());
        }

        // 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;

        XmlDsigC14NTransform xmlTransform =
            new XmlDsigC14NTransform();
        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/TR/2001/REC-xml-c14n-20010315" xmln
// s="http://www.w3.org/2000/09/xmldsig#" />
// Encoding the following xml: <PRODUCTS><PRODUCT><ID>123</ID><DESCRIPTION>Rou
// ter</DESCRIPTION></PRODUCT><PRODUCT><ID>456</ID><DESCRIPTION>Keyboard</DESC
// RIPTION></PRODUCT><!--Comments are included in the transform--><PARTNER_URL
// ><![CDATA['http:\\www.contoso.com\partner.asp?h1=en&h2=cr']]></PARTNER_URL>
// </PRODUCTS>Message encoded: <PRODUCTS><PRODUCT><ID>123</ID><DESCRIPTION>Rou
// ter</DESCRIPTION></PRODUCT><PRODUCT><ID>456</ID><DESCRIPTION>Keyboard</DESC
// RIPTION></PRODUCT><!--Comments are included in the transform--><PARTNER_URL
// >'http:\\www.contoso.com\partner.asp?h1=en&amp;h2=cr'</PARTNER_URL></PRODUC
// TS>

// Xml representation of the current transform:
// <Transform Algorithm="http://www.w3.org/TR/2001/REC-xml-c14n-20010315" xmln
// s="http://www.w3.org/2000/09/xmldsig#" />
// Encoding the following xml: <PRODUCTS><PRODUCT><ID>123</ID><DESCRIPTION>Rou
// ter</DESCRIPTION></PRODUCT><PRODUCT><ID>456</ID><DESCRIPTION>Keyboard</DESC
// RIPTION></PRODUCT><!--Comments are included in the transform--><PARTNER_URL
// ><![CDATA['http:\\www.contoso.com\partner.asp?h1=en&h2=cr']]></PARTNER_URL>
// <Signature xmlns="http://www.w3.org/2000/09/xmldsig#"><SignedInfo><Canonica
// lizationMethod 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/TR/2
// 001/REC-xml-c14n-20010315" /></Transforms><DigestMethod Algorithm="http://w
// ww.w3.org/2000/09/xmldsig#sha1" /><DigestValue>BFN2s0/NA2NGgb/R0mvfnNM0Ito=
// </DigestValue></Reference></SignedInfo><SignatureValue>vSfZUG5xHuNxzOSEbQjN
// dtEt1D+O7I1LTJ13RrwLaJSfQPrdT/s8IeaA+idw2f2WGuGrdqMJUddpE4GxfK61HmPQ6S7lBG+
// +ND+YaUYf2AtTRs3SnToXQQrARa/pHVjsKxYHR/9tjy6maHBwxjgjFQABvYZu0gZHYRuXvvfxv0
// 8=</SignatureValue><KeyInfo><X509Data xmlns="http://www.w3.org/2000/09/xmld
// sig#"><X509Certificate>MIICCzCCAXSgAwIBAgIQ5eVQY8pRZ5xBF2WLkYPjijANBgkqhkiG
// 9w0BAQQFADAbMRkwFwYDVQQDExBHcmVnc0NlcnRpZmljYXRlMB4XDTAzMDkxNzIzMzU0N1oXDTM
// 5MTIzMTIzNTk1OVowGzEZMBcGA1UEAxMQR3JlZ3NDZXJ0aWZpY2F0ZTCBnzANBgkqhkiG9w0BAQ
// EFAAOBjQAwgYkCgYEAmFJ4v7rS3BYTXgVW9PgBFfTYAcB/m9mOFCmUrrChcBpoEtu/tSESlNfEH
// pECIdqg9vUrCNSkY08HRn3ueNeBSnSpssWd8/XoOboWLh1nd+79Y5uZd1WOJI4s0XM0MegZgCoJ
// cEEhpxCd/HOPIQvEsbpN/DuFiovZLo+Ek3hHoxMCAwEAAaNQME4wTAYDVR0BBEUwQ4AQaCb19dl
// yf/zSxPVYQZY9AKEdMBsxGTAXBgNVBAMTEEdyZWdzQ2VydGlmaWNhdGWCEOXlUGPKUWecQRdli5
// GD44owDQYJKoZIhvcNAQEEBQADgYEAZuZaFDGDJogh7FuT0hfaMAVlRONv6wWVBJVV++eUo38Xu
// RfJ5nNJ0UnhiV2sEtLobYBPEIrNhuk8skdU0AHgx4ILiA4rR96ifWwxtrFQF+h+DL2ZB7xhwcOJ
// +Pa7IC4wIaEp/oBmmX+JHSzfQt6/If4ohwikfxfljKMyIcMlwl4=</X509Certificate></X50
// 9Data></KeyInfo></Signature></PRODUCTS>
//
// Message encoded: <PRODUCTS><PRODUCT><ID>123</ID><DESCRIPTION>Router</DESCRI
// PTION></PRODUCT><PRODUCT><ID>456</ID><DESCRIPTION>Keyboard</DESCRIPTION></P
// RODUCT><!--Comments are included in the transform--><PARTNER_URL>'http:\\ww
// w.contoso.com\partner.asp?h1=en&amp;h2=cr'</PARTNER_URL><Signature><SignedI
// nfo><CanonicalizationMethod Algorithm="http://www.w3.org/TR/2001/REC-xml-c1
// 4n-20010315"></CanonicalizationMethod><SignatureMethod Algorithm="http://ww
// w.w3.org/2000/09/xmldsig#rsa-sha1"></SignatureMethod><Reference URI=""><Tra
// nsforms><Transform Algorithm="http://www.w3.org/TR/2001/REC-xml-c14n-200103
// 15"></Transform></Transforms><DigestMethod Algorithm="http://www.w3.org/200
// 0/09/xmldsig#sha1"></DigestMethod><DigestValue>BFN2s0/NA2NGgb/R0mvfnNM0Ito=
// </DigestValue></Reference></SignedInfo><SignatureValue>vSfZUG5xHuNxzOSEbQjN
// dtEt1D+O7I1LTJ13RrwLaJSfQPrdT/s8IeaA+idw2f2WGuGrdqMJUddpE4GxfK61HmPQ6S7lBG+
// +ND+YaUYf2AtTRs3SnToXQQrARa/pHVjsKxYHR/9tjy6maHBwxjgjFQABvYZu0gZHYRuXvvfxv0
// 8=</SignatureValue><KeyInfo><X509Data xmlns="http://www.w3.org/2000/09/xmld
// sig#"><X509Certificate>MIICCzCCAXSgAwIBAgIQ5eVQY8pRZ5xBF2WLkYPjijANBgkqhkiG
// 9w0BAQQFADAbMRkwFwYDVQQDExBHcmVnc0NlcnRpZmljYXRlMB4XDTAzMDkxNzIzMzU0N1oXDTM
// 5MTIzMTIzNTk1OVowGzEZMBcGA1UEAxMQR3JlZ3NDZXJ0aWZpY2F0ZTCBnzANBgkqhkiG9w0BAQ
// EFAAOBjQAwgYkCgYEAmFJ4v7rS3BYTXgVW9PgBFfTYAcB/m9mOFCmUrrChcBpoEtu/tSESlNfEH
// pECIdqg9vUrCNSkY08HRn3ueNeBSnSpssWd8/XoOboWLh1nd+79Y5uZd1WOJI4s0XM0MegZgCoJ
// cEEhpxCd/HOPIQvEsbpN/DuFiovZLo+Ek3hHoxMCAwEAAaNQME4wTAYDVR0BBEUwQ4AQaCb19dl
// yf/zSxPVYQZY9AKEdMBsxGTAXBgNVBAMTEEdyZWdzQ2VydGlmaWNhdGWCEOXlUGPKUWecQRdli5
// GD44owDQYJKoZIhvcNAQEEBQADgYEAZuZaFDGDJogh7FuT0hfaMAVlRONv6wWVBJVV++eUo38Xu
// RfJ5nNJ0UnhiV2sEtLobYBPEIrNhuk8skdU0AHgx4ILiA4rR96ifWwxtrFQF+h+DL2ZB7xhwcOJ
// +Pa7IC4wIaEp/oBmmX+JHSzfQt6/If4ohwikfxfljKMyIcMlwl4=</X509Certificate></X50
// 9Data></KeyInfo></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, 3.5, 3.0, 2.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

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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