Imports System
Imports System.Security.Cryptography
Imports System.Security.Cryptography.Xml
Imports System.Xml



Module SignXML


    Sub Main(ByVal args() As String)
        Try
            ' Create a new CspParameters object to specify
            ' a key container.
            Dim cspParams As New CspParameters()
            cspParams.KeyContainerName = "XML_DSIG_RSA_KEY"
            ' Create a new RSA signing key and save it in the container. 
            Dim rsaKey As New RSACryptoServiceProvider(cspParams)
            ' Create a new XML document.
            Dim xmlDoc As New XmlDocument()

            ' Load an XML file into the XmlDocument object.
            xmlDoc.PreserveWhitespace = True
            xmlDoc.Load("test.xml")
            ' Sign the XML document. 
            SignXml(xmlDoc, rsaKey)

            Console.WriteLine("XML file signed.")

            ' Save the document.
            xmlDoc.Save("test.xml")


        Catch e As Exception
            Console.WriteLine(e.Message)
        End Try

    End Sub



    ' Sign an XML file. 
    ' This document cannot be verified unless the verifying 
    ' code has the key with which it was signed.
    Sub SignXml(ByVal Doc As XmlDocument, ByVal Key As RSA)
        ' Check arguments.
        If Doc Is Nothing Then
            Throw New ArgumentException("Doc")
        End If
        If Key Is Nothing Then
            Throw New ArgumentException("Key")
        End If
        ' Create a SignedXml object.
        Dim signedXml As New SignedXml(Doc)
        ' Add the key to the SignedXml document.
        signedXml.SigningKey = Key
        ' Create a reference to be signed.
        Dim reference As New Reference()
        reference.Uri = ""
        ' Add an enveloped transformation to the reference.
        Dim env As New XmlDsigEnvelopedSignatureTransform()
        reference.AddTransform(env)
        ' Add the reference to the SignedXml object.
        signedXml.AddReference(reference)
        ' Compute the signature.
        signedXml.ComputeSignature()
        ' Get the XML representation of the signature and save
        ' it to an XmlElement object.
        Dim xmlDigitalSignature As XmlElement = signedXml.GetXml()
        ' Append the element to the XML document.
        Doc.DocumentElement.AppendChild(Doc.ImportNode(xmlDigitalSignature, True))
    End Sub
End Module

using System;
using System.Security.Cryptography;
using System.Security.Cryptography.Xml;
using System.Xml;

public class SignXML
{

    public static void Main(String[] args)
    {
        try
        {
            // Create a new CspParameters object to specify
            // a key container.
            CspParameters cspParams = new CspParameters();
            cspParams.KeyContainerName = "XML_DSIG_RSA_KEY";

            // Create a new RSA signing key and save it in the container. 
            RSACryptoServiceProvider rsaKey = new RSACryptoServiceProvider(cspParams);

            // Create a new XML document.
            XmlDocument xmlDoc = new XmlDocument();

            // Load an XML file into the XmlDocument object.
            xmlDoc.PreserveWhitespace = true;
            xmlDoc.Load("test.xml");

            // Sign the XML document. 
            SignXml(xmlDoc, rsaKey);

            Console.WriteLine("XML file signed.");

            // Save the document.
            xmlDoc.Save("test.xml");



        }
        catch (Exception e)
        {
            Console.WriteLine(e.Message);
        }
    }


    // Sign an XML file. 
    // This document cannot be verified unless the verifying 
    // code has the key with which it was signed.
    public static void SignXml(XmlDocument Doc, RSA Key)
    {
        // Check arguments.
        if (Doc == null)
            throw new ArgumentException("Doc");
        if (Key == null)
            throw new ArgumentException("Key");

        // 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);

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

        // 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));

    }
}