(VB.NET UWP/WinRT) Examine KeyInfo Certificate in XML Signature

This example loads signed XML and gets the signing certificate, assuming the certificate is contained in X509Certificate within the KeyInfo.

Chilkat Universal Windows Platform (UWP) / WinRT Downloads Chilkat for the Universal Windows Platform (UWP)

' This example requires the Chilkat API to have been previously unlocked.
' See Global Unlock Sample for sample code.

Dim dsig As New Chilkat.XmlDSig
Dim sbXml As New Chilkat.StringBuilder

Dim success As Boolean = sbXml.LoadFile("c:/aaworkarea/elias/3/face_f09006808443a699d1b.xml","utf-8")
If (success <> True) Then
    Debug.WriteLine("Failed to load XML file.")
    Exit Sub
End If


success = dsig.LoadSignatureSb(sbXml)
If (success <> True) Then
    Debug.WriteLine(dsig.LastErrorText)
    Exit Sub
End If


' Get the KeyInfo XML.
Dim xmlKeyInfo As Chilkat.Xml = dsig.GetKeyInfo()
If (dsig.LastMethodSuccess <> True) Then
    Debug.WriteLine(dsig.LastErrorText)
    Exit Sub
End If


Debug.WriteLine(xmlKeyInfo.GetXml())
Debug.WriteLine("----")

' Assuming the X509Certificate is in the KeyInfo, it will look like this:

'   <ds:KeyInfo Id="...">
'     <ds:KeyValue>
'     ...  
'     <ds:X509Data>
'       <ds:X509Certificate>MIIHAz...</ds:X509Certificate>
'     </ds:X509Data>
'   </ds:KeyInfo>
Dim certBase64 As String = xmlKeyInfo.GetChildContent("*:X509Data|*:X509Certificate")
If (xmlKeyInfo.LastMethodSuccess <> True) Then
    Debug.WriteLine("No X509Certificate found in the KeyInfo.")
    Exit Sub
End If


' Load a certificate object w/ the base64.
Dim cert As New Chilkat.Cert
success = cert.LoadFromBase64(certBase64)
If (success <> True) Then
    Debug.WriteLine(cert.LastErrorText)
    Exit Sub
End If


' Examine the cert..
Debug.WriteLine("SubjectDN: " & cert.SubjectDN)
Debug.WriteLine("IssuerDN: " & cert.IssuerDN)
Debug.WriteLine("SerialNumber as Decimal: " & cert.SerialDecimal)