//
// This example signs an XML file using an
// envelope signature. It then verifies the 
// signed XML.
//
using System;
using System.Security.Cryptography;
using System.Security.Cryptography.X509Certificates;
using System.Security.Cryptography.Xml;
using System.Text;
using System.Xml;

public class SignVerifyEnvelope
{

    public static void Main(String[] args)
    {
        // Generate a signing key.
        RSACryptoServiceProvider Key = new RSACryptoServiceProvider();

        string xsl = @"
    <xs:transform xmlns:xs='http://www.w3.org/1999/XSL/Transform' version='1.0'>
        <xs:template match='/'>
            <xs:apply-templates/>
        </xs:template>
        <xs:template match='ElementToTransform'> 
            <transformedElement/>
        </xs:template>
    </xs:transform>";

        try
        {
            // Create an XML file to sign.
            CreateSomeXml("Example.xml");
            Console.WriteLine("New XML file created.");

            // Sign the XML that was just created and save it in a 
            // new file.
            SignXmlFile("Example.xml", "SignedExample.xml", Key, xsl);
            Console.WriteLine("XML file signed.");

            // Verify the signature of the signed XML.
            Console.WriteLine("Verifying signature...");
            bool result = VerifyXmlFile("SignedExample.xml");

            // Display the results of the signature verification to \
            // the console.
            if (result)
            {
                Console.WriteLine("The XML signature is valid.");
            }
            else
            {
                Console.WriteLine("The XML signature is not valid.");
            }
        }
        catch (CryptographicException e)
        {
            Console.WriteLine(e.Message);
        }
        finally
        {
            Key.Clear();
        }
    }

    // Sign an XML file and save the signature in a new file.
    public static void SignXmlFile(string FileName, string SignedFileName, RSA Key, string XSLString)
    {
        // Create a new XML document.
        XmlDocument doc = new XmlDocument();

        // Format the document to ignore white spaces.
        doc.PreserveWhitespace = false;

        // Load the passed XML file using it's name.
        doc.Load(new XmlTextReader(FileName));

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

        // 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.
        XmlDsigEnvelopedSignatureTransform env = new XmlDsigEnvelopedSignatureTransform();
        reference.AddTransform(env);

        // Create an XmlDsigXPathTransform object using 
        // the helper method 'CreateXPathTransform' defined
        // later in this sample.

        XmlDsigXsltTransform XsltTransform = CreateXsltTransform(XSLString);

        // Add the transform to the reference.
        reference.AddTransform(XsltTransform);

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

        // Add an RSAKeyValue KeyInfo (optional; helps recipient find key to validate).
        KeyInfo keyInfo = new KeyInfo();
        keyInfo.AddClause(new RSAKeyValue((RSA)Key));
        signedXml.KeyInfo = keyInfo;

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

        // Get the XML representation of the signature and save
        // it to an XmlElement object.
        XmlElement xmlDigitalSignature = signedXml.GetXml();

        // Append the element to the XML document.
        doc.DocumentElement.AppendChild(doc.ImportNode(xmlDigitalSignature, true));

        // Save the signed XML document to a file specified
        // using the passed string.
        XmlTextWriter xmltw = new XmlTextWriter(SignedFileName, new UTF8Encoding(false));
        doc.WriteTo(xmltw);
        xmltw.Close();
    }
    // Verify the signature of an XML file and return the result.
    public static Boolean VerifyXmlFile(String Name)
    {
        // Create a new XML document.
        XmlDocument xmlDocument = new XmlDocument();

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

        // Load the passed XML file into the document. 
        xmlDocument.Load(Name);

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

        // Find the "Signature" node and create a new
        // XmlNodeList object.
        XmlNodeList nodeList = xmlDocument.GetElementsByTagName("Signature");

        // Load the signature node.
        signedXml.LoadXml((XmlElement)nodeList[0]);

        // Check the signature and return the result.
        return signedXml.CheckSignature();
    }

    // Create the XML that represents the transform.
    public static XmlDsigXsltTransform CreateXsltTransform(string xsl)
    {
        XmlDocument doc = new XmlDocument();
        doc.LoadXml(xsl);

        XmlDsigXsltTransform xform = new XmlDsigXsltTransform();
        xform.LoadInnerXml(doc.ChildNodes);

        return xform;
    }

    // Create example data to sign.
    public static void CreateSomeXml(string FileName)
    {
        // Create a new XmlDocument object.
        XmlDocument document = new XmlDocument();

        // Create a new XmlNode object.
        XmlNode node = document.CreateNode(XmlNodeType.Element, "", "MyXML", "Don't_Sign");

        // Append the node to the document.
        document.AppendChild(node);

        // Create a new XmlNode object.
        XmlNode subnode = document.CreateNode(XmlNodeType.Element, "", "ElementToTransform", "Sign");

        // Add some text to the node.
        subnode.InnerText = "Here is some data to sign.";

        // Append the node to the document.
        document.DocumentElement.AppendChild(subnode);

        // Save the XML document to the file name specified.
        XmlTextWriter xmltw = new XmlTextWriter(FileName, new UTF8Encoding(false));
        document.WriteTo(xmltw);
        xmltw.Close();
    }
}

//引入命名空间
using System;
using System.IO;
using System.Xml;
using System.Security.Cryptography;
using System.Security.Cryptography.Xml;
using System.Text;

class Class1
{
    [STAThread]
    static void Main(string[] args)
    {
        XmlDocument productsXml = LoadProducts();
        XmlNodeList xsltNodeList = GetXsltAsNodeList();
        TransformDoc(productsXml, xsltNodeList);

        // Use XmlDsigXsltTransform 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();
    }

    private static void TransformDoc(
        XmlDocument xmlDoc, 
        XmlNodeList xsltNodeList)
    {
        try 
        {
            // Construct a new XmlDsigXsltTransform.
            XmlDsigXsltTransform xmlTransform = 
                new XmlDsigXsltTransform();

            // Load the Xslt tranform as a node list.
            xmlTransform.LoadInnerXml(xsltNodeList);

            // Load the Xml document to perform the tranform on.
            XmlNamespaceManager namespaceManager;
            namespaceManager = new XmlNamespaceManager(xmlDoc.NameTable);

            XmlNodeList productsNodeList;
            productsNodeList = xmlDoc.SelectNodes("//.", namespaceManager);

            xmlTransform.LoadInput(productsNodeList);

            // Retrieve the output from the transform.
            Stream outputStream = (Stream)
                xmlTransform.GetOutput(typeof(System.IO.Stream));

            // Read the output stream 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("\nResult of transformation: " + outputMessage);
            ShowTransformProperties(xmlTransform);
        }
        catch (Exception ex)
        {
            Console.WriteLine("Caught exception in TransformDoc method: " + 
                ex.ToString());
        }
    }
    
    private static XmlNodeList GetXsltAsNodeList()
    {
        string transformXml = "<xsl:transform version='1.0' ";
        transformXml += "xmlns:xsl='http://www.w3.org/1999/XSL/Transform'>";
        transformXml += "<xsl:template match='products'>";
        transformXml += "<table><tr><td>ProductId</td><td>Name</td></tr>";
        transformXml += "<xsl:apply-templates/></table></xsl:template>";
        transformXml += "<xsl:template match='product'><tr>";
        transformXml += "<xsl:apply-templates/></tr></xsl:template>";
        transformXml += "<xsl:template match='productid'><td>";
        transformXml += "<xsl:apply-templates/></td></xsl:template>";
        transformXml += "<xsl:template match='description'><td>";
        transformXml += "<xsl:apply-templates/></td></xsl:template>";
        transformXml += "</xsl:transform>";

        Console.WriteLine("\nCreated the following Xslt tranform:");
        Console.WriteLine(transformXml);

        XmlDocument xmlDoc = new XmlDocument();
        xmlDoc.LoadXml(transformXml);
        return xmlDoc.GetElementsByTagName("xsl:transform");
    }

    // Encrypt the text in the specified XmlDocument.
    private static void ShowTransformProperties(
        XmlDsigXsltTransform xmlTransform)
    {
        string classDescription = xmlTransform.ToString();
        Console.WriteLine("\n** Summary for " + classDescription + " **");

        // Retrieve the XML representation of the current transform.
        XmlElement xmlInTransform = xmlTransform.GetXml();
        Console.WriteLine("Xml representation of the current transform:\n" +
            xmlInTransform.OuterXml);

        // Ensure the transform is using the proper algorithm.
        xmlTransform.Algorithm =
            SignedXml.XmlDsigXsltTransformUrl;
        Console.WriteLine("Algorithm used: " + classDescription);

        // Retrieve the valid input types for the current transform.
        Type[] validInTypes = xmlTransform.InputTypes;
        Console.WriteLine("Transform accepts the following inputs:");
        for (int i=0; i<validInTypes.Length; i++)
        {
            Console.WriteLine("\t" + validInTypes[i].ToString());
        }

        Type[] validOutTypes = xmlTransform.OutputTypes;
        Console.WriteLine("Transform outputs in the following types:");
        for (int i=validOutTypes.Length-1; i >= 0; i--)
        {
            Console.WriteLine("\t " + validOutTypes[i].ToString());

            if (validOutTypes[i] == typeof(object))
            {
                object outputObject = xmlTransform.GetOutput();
            }
        }
    }

    // Create an XML document describing various products.
    private static XmlDocument LoadProducts()
    {
        string contosoProducts = "<?xml version='1.0'?>";
        contosoProducts += "<products>";
        contosoProducts += "<product><productid>1</productid>";
        contosoProducts += "<description>Widgets</description></product>";
        contosoProducts += "<product><productid>2</productid>";
        contosoProducts += "<description>Gadgits</description></product>";
        contosoProducts += "</products>";

        Console.WriteLine(
            "\nCreated the following Xml document for tranformation:");
        Console.WriteLine(contosoProducts);

        XmlDocument xmlDoc = new XmlDocument();
        xmlDoc.LoadXml(contosoProducts);
        return xmlDoc;
    }

    // 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;

        XmlDsigXsltTransform xmlTransform =
            new XmlDsigXsltTransform();
        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;
    }
}
//