Private Sub VerifyButton_Click(sender As Object, e As EventArgs) Handles VerifyButton.Click
' 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.LoadXml(ToVerifyTextBox.Text)
' 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", "http://www.w3.org/2000/09/xmldsig#")
If nodeList.Count <= 0 Then
MessageBox.Show("Verification failed: No Signature was found in the document.")
' This example only supports one signature for
' the entire XML document. Throw an exception
' if more than one signature was found.
ElseIf nodeList.Count >= 2 Then
MessageBox.Show("Verification failed: More that one signature was found for the document.")
Else
' Load the signature node.
'
signedXml.LoadXml(CType(nodeList(0), XmlElement))
' Check the signature and show the result.
'
If signedXml.CheckSignature() Then
MessageBox.Show("Signature verified!")
Else
MessageBox.Show("Invalid signature!!!")
End If
End If
End Sub
This code will go trough the xml file and find the tag signature and the signature verified as valid, but I want to check and compare the key with the key in the xml file and if it is ok than to signature verified as valid.
I resolved this.
This is my code that I use to verify xml document:
Public Function VerifyXml(Doc As XmlDocument, Key As String) As Boolean
Dim tmpRsa As New RSACryptoServiceProvider()
tmpRsa.FromXmlString(Key)
'VERIFY ALL ARGUMENTS HAVE BEEN PASSED IN
If Doc Is Nothing Then
Throw New ArgumentException("Doc")
End If
If Key Is Nothing Then
Throw New ArgumentException("Key")
End If
'HOLD THE SIGNED DOCUMENT
Dim signedXml As New SignedXml(Doc)
'LOCATE THE SIGNATURE NODE IN THE DOCUMENT
Dim nodeList As XmlNodeList = Doc.GetElementsByTagName("Signature")
'IF WE CANT FIND THE NODE THEN THIS DOCUMENT IS NOT SIGNED
If nodeList.Count <= 0 Then
Throw New CryptographicException("Verification failed: No Signature was found in the document.")
End If
'IF THERE ARE MORE THEN ONE SIGNATURES THEN FAIL
If nodeList.Count >= 2 Then
Throw New CryptographicException("Verification failed: More that one signature was found for the document.")
End If
'LOAD THE SIGNATURE NODE INTO THE SIGNEDXML DOCUMENT
signedXml.LoadXml(DirectCast(nodeList(0), XmlElement))
'CHECK THE SIGNATURE AND SEND THE RESULT
Return signedXml.CheckSignature(tmpRsa)
End Function