AutoIt

Verify XML Signature with External URL References

See more XML Digital Signatures Examples

Demonstrates how to verify an XML digital signature that includes references to URLs where the data to be digested is on a web server. AutoIt

Local $bSuccess = False

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

; The signed XML we wish to verify contains external references such as this:

;     <ds:Reference Id="xmldsig-e7ae7ce2-9133-4d56-bd97-0a6aef738cc2-ref0" URI="https://www.chilkatsoft.com/images/starfish.jpg">
;       <ds:DigestMethod Algorithm="http://www.w3.org/2001/04/xmlenc#sha256"/>
;       <ds:DigestValue>AOU810yJV5Np/DnO29qpObqiTSTTCDvxGsX5ayiTYXI=</ds:DigestValue>
;     </ds:Reference>
;     <ds:Reference Id="xmldsig-e7ae7ce2-9133-4d56-bd97-0a6aef738cc2-ref1" URI="https://www.chilkatsoft.com/hamlet.xml">
;       <ds:DigestMethod Algorithm="http://www.w3.org/2001/04/xmlenc#sha256"/>
;       <ds:DigestValue>4sRRyWOzC7EOic4fQ9+Op1pa10DbgoBGjBvkq09LZmE=</ds:DigestValue>
;     </ds:Reference>

$oVerifier = ObjCreate("Chilkat.XmlDSig")
$oHttp = ObjCreate("Chilkat.Http")

; First load the signed XML
$oSbSignedXml = ObjCreate("Chilkat.StringBuilder")
$bSuccess = $oSbSignedXml.LoadFile("qa_data/xml_dsig_verify/signedWithExternalUrlRefs.xml","utf-8")
If ($bSuccess = False) Then
    ConsoleWrite("Failed to load signed XML." & @CRLF)
    Exit
EndIf

$bSuccess = $oVerifier.LoadSignatureSb($oSbSignedXml)
If ($bSuccess = False) Then
    ConsoleWrite($oVerifier.LastErrorText & @CRLF)
    Exit
EndIf

; Iterate over each reference.  If it is an external URL reference, download the data and provide it to the verifier.
$oSbRefUri = ObjCreate("Chilkat.StringBuilder")
$oBd = ObjCreate("Chilkat.BinData")
Local $iNumRefs = $oVerifier.NumReferences
Local $i = 0
While $i < $iNumRefs
    If ($oVerifier.IsReferenceExternal($i) = True) Then
        $oSbRefUri.Clear 
        $oSbRefUri.Append($oVerifier.ReferenceUri($i))
        If ($oSbRefUri.StartsWith("https://",False) = True) Then
            ConsoleWrite("External URL Reference: " & $oSbRefUri.GetAsString() & @CRLF)

            ; Download the data at the URL and provide to the verifier.
            $bSuccess = $oHttp.DownloadBd($oSbRefUri.GetAsString(),$oBd)
            If ($bSuccess = False) Then
                ConsoleWrite($oHttp.LastErrorText & @CRLF)
                Exit
            EndIf

            $bSuccess = $oVerifier.SetRefDataBd($i,$oBd)
            If ($bSuccess = False) Then
                ConsoleWrite($oVerifier.LastErrorText & @CRLF)
                Exit
            EndIf

        EndIf

    EndIf

    $i = $i + 1
Wend

; Now that we have the external data, verify the signature..
Local $bVerified = $oVerifier.VerifySignature(True)
If ($bVerified = False) Then
    ConsoleWrite($oVerifier.LastErrorText & @CRLF)
EndIf

ConsoleWrite("Signature verified = " & $bVerified & @CRLF)