'
' This example signs a file specified by a URI 
' using a detached signature. It then verifies  
' the signed XML.
'
Imports System.Security.Cryptography
Imports System.Security.Cryptography.Xml
Imports System.Text
Imports System.Xml


Class XMLDSIGDetached

   
   <STAThread()>  _
   Overloads Shared Sub Main(args() As String)
      ' The URI to sign.
      Dim resourceToSign As String = "http://www.microsoft.com"
      
      ' The name of the file to which to save the XML signature.
      Dim XmlFileName As String = "xmldsig.xml"
      
      Try
         
         ' Generate a signing key.
         Dim Key As New RSACryptoServiceProvider()
         
         Console.WriteLine("Signing: {0}", resourceToSign)
         
         ' Sign the detached resourceand save the signature in an XML file.
         SignDetachedResource(resourceToSign, XmlFileName, Key)
         
         Console.WriteLine("XML signature was succesfully computed and saved to {0}.", XmlFileName)
         
         ' Verify the signature of the signed XML.
         Console.WriteLine("Verifying signature...")
         
         'Verify the XML signature in the XML file.
         Dim result As Boolean = VerifyDetachedSignature(XmlFileName)
         
         ' 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)
      End Try 
   End Sub 
   
   
   ' Sign an XML file and save the signature in a new file.
   Public Shared Sub SignDetachedResource(URIString As String, XmlSigFileName As String, Key As RSA)
      ' Create a SignedXml object.
      Dim signedXml As New SignedXml()
      
      ' Assign the key to the SignedXml object.
      signedXml.SigningKey = Key
      
      ' Create a reference to be signed.
      Dim reference As New Reference()
      
      ' Add the passed URI to the reference object.
      reference.Uri = URIString
      
      ' 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()
      
      ' Save the signed XML document to a file specified
      ' using the passed string.
      Dim xmltw As New XmlTextWriter(XmlSigFileName, New UTF8Encoding(False))
      xmlDigitalSignature.WriteTo(xmltw)
      xmltw.Close()
   End Sub 
 
   ' Verify the signature of an XML file and return the result.
   Public Shared Function VerifyDetachedSignature(XmlSigFileName As String) As [Boolean]
      ' Create a new XML document.
      Dim xmlDocument As New XmlDocument()
      
      ' Load the passed XML file into the document.
      xmlDocument.Load(XmlSigFileName)
      
      ' Create a new SignedXMl object.
      Dim signedXml As New SignedXml()
      
      ' 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
End Class

' 导入命名空间
Imports System.IO
Imports System.Xml
Imports System.Security.Cryptography
Imports System.Security.Cryptography.Xml
Imports System.Security.Cryptography.X509Certificates

Public Class Form1
    Inherits System.Windows.Forms.Form

    Private certificateFilePath As String = "..\\my509.cer"

    ' 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 = ""

        ' Encrypt an XML message
        Dim productsXml As XmlDocument = LoadProducts()
        ShowTransformProperties(productsXml)

        SignDocument(productsXml)
        ShowTransformProperties(productsXml)

        ' Use XmlDsigC14NTransform 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

    ' Encrypt the text in the specified XmlDocument.
    Private Sub ShowTransformProperties(ByVal xmlDoc As XmlDocument)
        Dim xmlTransform As New XmlDsigC14NTransform(True)

        ' Ensure the transform is using the appropriate algorithm.
        xmlTransform.Algorithm = _
            SignedXml.XmlDsigExcC14NTransformUrl

        ' Retrieve the XML representation of the current transform.
        Dim xmlInTransform As XmlElement = xmlTransform.GetXml()

        WriteLine(vbCrLf + "Xml representation of the current transform: ")
        WriteLine(xmlInTransform.OuterXml)

        ' Retrieve the valid input types for the current transform.
        Dim validInTypes() As Type = xmlTransform.InputTypes

        ' Verify the xmlTransform can accept the XMLDocument as an
        ' input type.
        For i As Int16 = 0 To validInTypes.Length Step 1
            If (validInTypes(i).Equals(xmlDoc.GetType())) Then
                ' Load the document into the transfrom.
                xmlTransform.LoadInput(xmlDoc)

                Dim secondTransform As New XmlDsigC14NTransform

                Dim classDescription As String = secondTransform.ToString()

                ' This call does not perform as expected.
                ' This transform does not contain inner XML elements
                secondTransform.LoadInnerXml(xmlDoc.SelectNodes("//."))
                Exit For
            End If
        Next

        Dim validOutTypes() As Type = xmlTransform.OutputTypes
        For i As Int16 = 0 To validOutTypes.Length - 1 Step 1
            If (validOutTypes(i).Equals(GetType(System.IO.Stream))) Then
                Try
                    Dim streamType As Type = GetType(System.IO.Stream)
                    Dim outputStream As MemoryStream
                    outputStream = CType( _
                        xmlTransform.GetOutput(streamType), _
                        MemoryStream)

                    ' Read the CryptoStream 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("Encoding the following xml: " + _
                        xmlDoc.OuterXml)
                    WriteLine("Message encoded: " + outputMessage)

                Catch ex As Exception
                    WriteLine("Unexpected exception caught: " + ex.ToString())

                End Try
            Else
                Dim outputObject As Object = xmlTransform.GetOutput()

            End If
        Next
    End Sub

    ' Create an XML document describing various products.
    Private Function LoadProducts() As XmlDocument
        Dim xmlDoc As New XmlDocument

        Dim contosoProducts As String = "<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
    End Function

    ' Create a signature and add it to the specified document.
    Private Sub SignDocument(ByRef xmlDoc As XmlDocument)
        ' Generate a signing key.
        Dim Key As New RSACryptoServiceProvider

        ' Create a SignedXml object.
        Dim signedXml As New SignedXml(xmlDoc)

        ' 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.
        reference.AddTransform(New XmlDsigC14NTransform)

        ' Add the reference to the SignedXml object.
        signedXml.AddReference(reference)

        Try
            ' Create a new KeyInfo object.
            Dim keyInfo As New KeyInfo

            ' Load the X509 certificate.
            Dim certificate As X509Certificate
            certificate = X509Certificate.CreateFromCertFile( _
                certificateFilePath)

            ' Load the certificate into a KeyInfoX509Data object
            ' and add it to the KeyInfo object.
            keyInfo.AddClause(New KeyInfoX509Data(certificate))

            ' Add the KeyInfo object to the SignedXml object.
            signedXml.KeyInfo = keyInfo
        Catch ex As FileNotFoundException
            WriteLine("Unable to locate the following file: " + _
                certificateFilePath)
        Catch ex As CryptographicException
            WriteLine("Unexpected exception caught whild creating " + _
                "the certificate:" + ex.ToString())
        End Try

        ' Compute the signature.
        signedXml.ComputeSignature()

        ' Add the signature branch to the original tree so it is enveloped.
        xmlDoc.DocumentElement.AppendChild(signedXml.GetXml())
    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 XmlDsigC14NTransform
        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 = "XmlDsigC14NTransform"
        Me.Panel2.ResumeLayout(False)
        Me.Panel1.ResumeLayout(False)
        Me.ResumeLayout(False)

    End Sub

#End Region
End Class