(Xojo Plugin) 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 Xojo Plugin Download Xojo Plugin for Windows, Linux, Mac OS X, and ARM, ARM64

// 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
success = sbXml.LoadFile("c:/aaworkarea/elias/3/face_f09006808443a699d1b.xml","utf-8")
If (success <> True) Then
    System.DebugLog("Failed to load XML file.")
    Return
End If

success = dsig.LoadSignatureSb(sbXml)
If (success <> True) Then
    System.DebugLog(dsig.LastErrorText)
    Return
End If

// Get the KeyInfo XML.
Dim xmlKeyInfo As Chilkat.Xml
xmlKeyInfo = dsig.GetKeyInfo()
If (dsig.LastMethodSuccess <> True) Then
    System.DebugLog(dsig.LastErrorText)
    Return
End If

System.DebugLog(xmlKeyInfo.GetXml())
System.DebugLog("----")

// 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
certBase64 = xmlKeyInfo.GetChildContent("*:X509Data|*:X509Certificate")
If (xmlKeyInfo.LastMethodSuccess <> True) Then
    System.DebugLog("No X509Certificate found in the KeyInfo.")
    Return
End If

// Load a certificate object w/ the base64.
Dim cert As New Chilkat.Cert
success = cert.LoadFromBase64(certBase64)
If (success <> True) Then
    System.DebugLog(cert.LastErrorText)
    Return
End If

// Examine the cert..
System.DebugLog("SubjectDN: " + cert.SubjectDN)
System.DebugLog("IssuerDN: " + cert.IssuerDN)
System.DebugLog("SerialNumber as Decimal: " + cert.SerialDecimal)