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



Module SignVerifyEnvelope


    Sub Main(ByVal args() As String)
        ' Generate a signing key.
        Dim Key As New RSACryptoServiceProvider()

        Dim xsl As String = "<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...")
            Dim result As Boolean = VerifyXmlFile("SignedExample.xml")

            ' Display the results of the signature verification to \
            ' the console.
            If result Then
                Console.WriteLine("The XML signature is valid.")
            Else
                Console.WriteLine("The XML signature is not valid.")
            End If
        Catch e As CryptographicException
            Console.WriteLine(e.Message)
        Finally
            Key.Clear()
        End Try

    End Sub


    ' Sign an XML file and save the signature in a new file.
    Sub SignXmlFile(ByVal FileName As String, ByVal SignedFileName As String, ByVal Key As RSA, ByVal XSLString As String)
        ' Create a new XML document.
        Dim doc As 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.
        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)

        ' Create an XmlDsigXPathTransform object using 
        ' the helper method 'CreateXPathTransform' defined
        ' later in this sample.
        Dim XsltTransform As XmlDsigXsltTransform = 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).
        Dim keyInfo As New KeyInfo()
        keyInfo.AddClause(New RSAKeyValue(CType(Key, RSA)))
        signedXml.KeyInfo = keyInfo

        ' 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))

        ' Save the signed XML document to a file specified
        ' using the passed string.
        Dim xmltw As New XmlTextWriter(SignedFileName, New UTF8Encoding(False))
        doc.WriteTo(xmltw)
        xmltw.Close()

    End Sub

    ' Verify the signature of an XML file and return the result.
    Function VerifyXmlFile(ByVal Name As String) As [Boolean]
        ' Create a new XML document.
        Dim xmlDocument As 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.
        Dim signedXml As New SignedXml(xmlDocument)

        ' Find the "Signature" node and create a new
        ' XmlNodeList object.
        Dim nodeList As XmlNodeList = xmlDocument.GetElementsByTagName("Signature")

        ' Load the signature node.
        signedXml.LoadXml(CType(nodeList(0), XmlElement))

        ' Check the signature and return the result.
        Return signedXml.CheckSignature()

    End Function


    ' Create the XML that represents the transform.
    Function CreateXsltTransform(ByVal xsl As String) As XmlDsigXsltTransform
        Dim doc As New XmlDocument()
        doc.LoadXml(xsl)

        Dim xform As New XmlDsigXsltTransform()
        xform.LoadInnerXml(doc.ChildNodes)

        Return xform

    End Function


    ' Create example data to sign.
    Sub CreateSomeXml(ByVal FileName As String)
        ' Create a new XmlDocument object.
        Dim document As New XmlDocument()

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

        ' Append the node to the document.
        document.AppendChild(node)

        ' Create a new XmlNode object.
        Dim subnode As XmlNode = 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.
        Dim xmltw As New XmlTextWriter(FileName, New UTF8Encoding(False))
        document.WriteTo(xmltw)
        xmltw.Close()

    End Sub
End Module

' 导入命名空间
Imports System.IO
Imports System.Xml
Imports System.Security.Cryptography
Imports System.Security.Cryptography.Xml
Imports System.Text

Public Class Form1
    Inherits System.Windows.Forms.Form

    ' Event handler for Run button.
    Private Sub Button1_Click( _
        ByVal sender As System.Object, _
        ByVal e As System.EventArgs) Handles Button1.Click

        tbxOutput.Cursor = Cursors.WaitCursor
        tbxOutput.Text = ""

        Dim productsXml As XmlDocument = LoadProducts()
        Dim xsltNodeList As XmlNodeList = GetXsltAsNodeList()
        TransformDoc(productsXml, xsltNodeList)

        ' Use XmlDsigXsltTransform to resolve a Uri.
        Dim baseUri As New Uri("http://www.contoso.com")
        Dim relativeUri As String = "xml"
        Dim absoluteUri As Uri = ResolveUris(baseUri, relativeUri)

        ' Align interface and conclude application.
        WriteLine(vbCrLf + "This sample completed successfully;" + _
            " press Exit to continue.")

        ' Reset the cursor.
        tbxOutput.Cursor = Cursors.Default
    End Sub

    ' Create an XML document describing various products.
    Private Function LoadProducts() As XmlDocument
        Dim contosoProducts As String = "<?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>"

        WriteLine(vbCrLf + _
            "Created the following Xml document for tranformation:")
        WriteLine(contosoProducts)

        Dim xmlDoc As New XmlDocument
        xmlDoc.LoadXml(contosoProducts)
        Return xmlDoc
    End Function

    Private Function GetXsltAsNodeList() As XmlNodeList
        Dim transformXml As String = "<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>"

        WriteLine(vbCrLf + "Created the following Xslt tranform:")
        WriteLine(transformXml)

        Dim xmlDoc As New XmlDocument
        xmlDoc.LoadXml(transformXml)
        Return xmlDoc.GetElementsByTagName("xsl:transform")
    End Function

    Private Sub TransformDoc( _
        ByVal xmlDoc As XmlDocument, _
        ByVal xsltNodeList As XmlNodeList)

        Try
            ' Construct a new XmlDsigXsltTransform.
            Dim xmlTransform As New XmlDsigXsltTransform

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

            ' Load the Xml document to perform the tranform on.
            dim namespaceManager as New XmlNamespaceManager(xmlDoc.NameTable)

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

            xmlTransform.LoadInput(productsNodeList)

            ' Retrieve the output from the transform.
            Dim outputStream As Stream
            outputStream = CType(xmlTransform.GetOutput( _
                GetType(System.IO.Stream)), _
                System.IO.Stream)

            ' Read the output stream into a stream reader.
            Dim streamReader As New StreamReader(outputStream)

            ' Read the stream into a string.
            Dim outputMessage As String = streamReader.ReadToEnd()

            ' Close the streams.
            outputStream.Close()
            streamReader.Close()

            ' Display to the console the Xml before and after encryption.
            WriteLine(vbCrLf + "Result of transformation: " + outputMessage)
            ShowTransformProperties(xmlTransform)
        Catch ex As Exception
            WriteLine("Caught exception in TransformDoc method: " + _
                ex.ToString())
        End Try
    End Sub

    Private Sub ShowTransformProperties( _
            ByVal xmlTransform As XmlDsigXsltTransform)

        Dim classDescription As String = xmlTransform.ToString()
        WriteLine(vbCrLf + "** Summary for " + classDescription + " **")

        ' Retrieve the XML representation of the current transform.
        Dim xmlInTransform As XmlElement = xmlTransform.GetXml()
        WriteLine("Xml representation of the current transform:" + _
            vbCrLf + 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.
        Dim validInTypes() As Type = xmlTransform.InputTypes
        WriteLine("Transform accepts the following inputs:")
        For i As Int16 = 0 To validInTypes.Length - 1 Step 1
            WriteLine("   " + validInTypes(i).ToString())
        Next

        Dim validOutTypes() As Type = xmlTransform.OutputTypes
        WriteLine("Transform outputs in the following types:")
        For j As Int16 = 0 To validOutTypes.Length - 1 Step 1

            WriteLine("   " + validOutTypes(j).ToString())
            If (validOutTypes(j).Equals(GetType(Object))) Then
                Dim outputObject As Object = xmlTransform.GetOutput()
            End If
        Next
    End Sub

    ' Resolve the specified base and relative Uri's .
    Private Function ResolveUris( _
        ByVal baseUri As Uri, _
        ByVal relativeUri As String) As Uri

        Dim xmlResolver As New XmlUrlResolver
        xmlResolver.Credentials = _
            System.Net.CredentialCache.DefaultCredentials

        Dim xmlTransform As New XmlDsigXsltTransform
        xmlTransform.Resolver = xmlResolver

        Dim absoluteUri As Uri = xmlResolver.ResolveUri(baseUri, relativeUri)
        If (Not absoluteUri Is Nothing) Then
            WriteLine(vbCrLf + _
                "Resolved the base Uri and relative Uri to the following:")
            WriteLine(absoluteUri.ToString())
        Else
            WriteLine("Unable to resolve the base Uri and relative Uri")
        End If
        
        Return absoluteUri
    End Function

    ' Write specified message and carriage return to the output textbox.
    Private Sub WriteLine(ByVal message As String)
        tbxOutput.AppendText(message + vbCrLf)

    End Sub

    ' Event handler for Exit button.
    Private Sub Button2_Click( _
        ByVal sender As System.Object, _
        ByVal e As System.EventArgs) Handles Button2.Click

        Application.Exit()
    End Sub
#Region " Windows Form Designer generated code "

    Public Sub New()
        MyBase.New()

        'This call is required by the Windows Form Designer.
        InitializeComponent()

        'Add any initialization after the InitializeComponent() call

    End Sub

    'Form overrides dispose to clean up the component list.
    Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean)
        If disposing Then
            If Not (components Is Nothing) Then
                components.Dispose()
            End If
        End If
        MyBase.Dispose(disposing)
    End Sub

    'Required by the Windows Form Designer
    Private components As System.ComponentModel.IContainer

    'NOTE: The following procedure is required by the Windows Form Designer
    'It can be modified using the Windows Form Designer.  
    'Do not modify it using the code editor.
    Friend WithEvents Panel2 As System.Windows.Forms.Panel
    Friend WithEvents Panel1 As System.Windows.Forms.Panel
    Friend WithEvents Button1 As System.Windows.Forms.Button
    Friend WithEvents Button2 As System.Windows.Forms.Button
    Friend WithEvents tbxOutput As System.Windows.Forms.RichTextBox
    <System.Diagnostics.DebuggerStepThrough()> _
    Private Sub InitializeComponent()
        Me.Panel2 = New System.Windows.Forms.Panel
        Me.Button1 = New System.Windows.Forms.Button
        Me.Button2 = New System.Windows.Forms.Button
        Me.Panel1 = New System.Windows.Forms.Panel
        Me.tbxOutput = New System.Windows.Forms.RichTextBox
        Me.Panel2.SuspendLayout()
        Me.Panel1.SuspendLayout()
        Me.SuspendLayout()
        '
        'Panel2
        '
        Me.Panel2.Controls.Add(Me.Button1)
        Me.Panel2.Controls.Add(Me.Button2)
        Me.Panel2.Dock = System.Windows.Forms.DockStyle.Bottom
        Me.Panel2.DockPadding.All = 20
        Me.Panel2.Location = New System.Drawing.Point(0, 320)
        Me.Panel2.Name = "Panel2"
        Me.Panel2.Size = New System.Drawing.Size(616, 64)
        Me.Panel2.TabIndex = 1
        '
        'Button1
        '
        Me.Button1.Dock = System.Windows.Forms.DockStyle.Right
        Me.Button1.Font = New System.Drawing.Font( _
            "Microsoft Sans Serif", _
            9.0!, _
            System.Drawing.FontStyle.Regular, _
            System.Drawing.GraphicsUnit.Point, _
            CType(0, Byte))
        Me.Button1.Location = New System.Drawing.Point(446, 20)
        Me.Button1.Name = "Button1"
        Me.Button1.Size = New System.Drawing.Size(75, 24)
        Me.Button1.TabIndex = 2
        Me.Button1.Text = "&Run"
        '
        'Button2
        '
        Me.Button2.Dock = System.Windows.Forms.DockStyle.Right
        Me.Button2.Font = New System.Drawing.Font( _
            "Microsoft Sans Serif", _
            9.0!, _
            System.Drawing.FontStyle.Regular, _
            System.Drawing.GraphicsUnit.Point, _
            CType(0, Byte))
        Me.Button2.Location = New System.Drawing.Point(521, 20)
        Me.Button2.Name = "Button2"
        Me.Button2.Size = New System.Drawing.Size(75, 24)
        Me.Button2.TabIndex = 3
        Me.Button2.Text = "E&xit"
        '
        'Panel1
        '
        Me.Panel1.Controls.Add(Me.tbxOutput)
        Me.Panel1.Dock = System.Windows.Forms.DockStyle.Fill
        Me.Panel1.DockPadding.All = 20
        Me.Panel1.Location = New System.Drawing.Point(0, 0)
        Me.Panel1.Name = "Panel1"
        Me.Panel1.Size = New System.Drawing.Size(616, 320)
        Me.Panel1.TabIndex = 2
        '
        'tbxOutput
        '
        Me.tbxOutput.AccessibleDescription = _
            "Displays output from application."
        Me.tbxOutput.AccessibleName = "Output textbox."
        Me.tbxOutput.Dock = System.Windows.Forms.DockStyle.Fill
        Me.tbxOutput.Location = New System.Drawing.Point(20, 20)
        Me.tbxOutput.Name = "tbxOutput"
        Me.tbxOutput.Size = New System.Drawing.Size(576, 280)
        Me.tbxOutput.TabIndex = 1
        Me.tbxOutput.Text = "Click the Run button to run the application."
        '
        'Form1
        '
        Me.AutoScaleBaseSize = New System.Drawing.Size(6, 15)
        Me.ClientSize = New System.Drawing.Size(616, 384)
        Me.Controls.Add(Me.Panel1)
        Me.Controls.Add(Me.Panel2)
        Me.Name = "Form1"
        Me.Text = "XmlDsigXsltTransform"
        Me.Panel2.ResumeLayout(False)
        Me.Panel1.ResumeLayout(False)
        Me.ResumeLayout(False)

    End Sub

#End Region
End Class