(VB.NET UWP/WinRT) SII Chile - FRMT Signature Computation and Add to XML

Compute the FRMT signature and add to the XML. This is the RSA signature of the SHA-1 digest of the "flattened" DD element.

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

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


' Also see:  Compute the FRMA Signature and Add to XML


Dim xml As New Chilkat.Xml

' Load the unsigned XML that contains the following:

' <DTE version="1.0">
'   <Documento ID="F60T33">
'         <TED version="1.0">
'             <DD>
' 		...
'                 <CAF version="1.0">
'                     <DA>
' 			...
'                     </DA>
'                     <FRMA algoritmo="SHA1withRSA">...</FRMA>
'                 </CAF>
'                 ...
'             </DD>
'             ... The FRMT will be added here in another example ...
'         </TED>
'   </Documento>
' </DTE>

Dim success As Boolean = xml.LoadXmlFile("qa_data/xml_dsig/sii_cl/test_1.xml")
If (success = False) Then
    Debug.WriteLine("Failed to load initial XML file.")
    Exit Sub
End If


' Get a reference to the "DD" element
Dim ddXml As Chilkat.Xml = xml.FindChild("Documento|TED|DD")
If (xml.LastMethodSuccess = False) Then
    Debug.WriteLine("Failed to find DD element")
    Exit Sub
End If


'  We need to get the "flattened" DD XML where:
'    - No whitespace between elements.
'    - The 5 pre-defined entities are converted.
'    - The text is encoded in the ISO-8859-1 character set (Latin-1), 
Dim sbFlattened As New Chilkat.StringBuilder
ddXml.EmitCompact = True
ddXml.EmitXmlDecl = False
ddXml.GetXmlSb(sbFlattened)

' Compute the SHA-1 message digest of the iso-8859-1 byte representation, 
' and sign it with our RSA private key, getting the result in base64 format.

Dim privKey As New Chilkat.PrivateKey
success = privKey.LoadAnyFormatFile("qa_data/rsa/rsaPrivKey_pkcs8.pem","")
If (success = False) Then
    Debug.WriteLine(privKey.LastErrorText)
    Exit Sub
End If


Dim rsa As New Chilkat.Rsa
rsa.ImportPrivateKeyObj(privKey)

rsa.EncodingMode = "base64"
rsa.Charset = "iso-8859-1"
Dim sig As String = rsa.SignStringENC(sbFlattened.GetAsString(),"sha1")

' Add the FRMT signature element to the XML.
xml.UpdateChildContent("Documento|TED|FRMT",sig)
xml.UpdateAttrAt("Documento|TED|FRMT",True,"algoritmo","SHA1withRSA")



' See what we have:
xml.EmitCompact = False
xml.EmitXmlDecl = True
Debug.WriteLine(xml.GetXml())