(VB.NET) Create JPK VAT metadata XML

Demonstrates how to create the JPK VAT metadata XML (InitUpload) that will be signed using XADES.

Note: This example requires Chilkat v11.0.0 or greater.

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Dim success As Boolean = False

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

' First build an InitUpload XML template

' Use this online tool to generate the code from the sample XML below: 
' Generate Code to Create XML

' <InitUpload xmlns="http://e-dokumenty.mf.gov.pl">
'     <DocumentType>JPK</DocumentType>
'     <Version>01.02.01.20160617</Version>
'     <EncryptionKey algorithm="RSA" encoding="Base64" mode="ECB" padding="PKCS#1">F9EhKFec...uWqAWUIg==</EncryptionKey>
'     <DocumentList>
'         <Document>
'             <FormCode schemaVersion="1-1" systemCode="JPK_VAT (3)">JPK_VAT</FormCode>
'             <FileName>JPK_VAT_3_v1-1_20181201.xml</FileName>
'             <ContentLength>8736</ContentLength>
'             <HashValue algorithm="SHA-256" encoding="Base64">JFDI1pItwh6dj/Xe1uts/x61qnjZ4DLHpkZMhmf1oKQ=</HashValue>
'             <FileSignatureList filesNumber="1">
'                 <Packaging>
'                     <SplitZip mode="zip" type="split"/>
'                 </Packaging>
'                 <Encryption>
'                     <AES block="16" mode="CBC" padding="PKCS#7" size="256">
'                         <IV bytes="16" encoding="Base64">z64oN9zXHt1+S3XACRSCYw==</IV>
'                     </AES>
'                 </Encryption>
'                 <FileSignature>
'                     <OrdinalNumber>1</OrdinalNumber>
'                     <FileName>JPK_VAT_3_v1-1_20181201-000.xml.zip.aes</FileName>
'                     <ContentLength>16</ContentLength>
'                     <HashValue algorithm="MD5" encoding="Base64">5NX0q1935fvMjLFV7E1yDw==</HashValue>
'                 </FileSignature>
'             </FileSignatureList>
'         </Document>
'     </DocumentList>
' </InitUpload>

Dim xml As New Chilkat.Xml
xml.Tag = "InitUpload"
xml.AddAttribute("xmlns","http://e-dokumenty.mf.gov.pl")
xml.UpdateChildContent("DocumentType","JPK")
xml.UpdateChildContent("Version","01.02.01.20160617")
xml.UpdateAttrAt("EncryptionKey",True,"algorithm","RSA")
xml.UpdateAttrAt("EncryptionKey",True,"encoding","Base64")
xml.UpdateAttrAt("EncryptionKey",True,"mode","ECB")
xml.UpdateAttrAt("EncryptionKey",True,"padding","PKCS#1")
xml.UpdateChildContent("EncryptionKey","TO BE DETERMINED")
xml.UpdateAttrAt("DocumentList|Document|FormCode",True,"schemaVersion","1-1")
xml.UpdateAttrAt("DocumentList|Document|FormCode",True,"systemCode","JPK_VAT (3)")
xml.UpdateChildContent("DocumentList|Document|FormCode","JPK_VAT")
xml.UpdateChildContent("DocumentList|Document|FileName","JPK_VAT_3_v1-1_20181201.xml")
xml.UpdateChildContent("DocumentList|Document|ContentLength","9999")
xml.UpdateAttrAt("DocumentList|Document|HashValue",True,"algorithm","SHA-256")
xml.UpdateAttrAt("DocumentList|Document|HashValue",True,"encoding","Base64")
xml.UpdateChildContent("DocumentList|Document|HashValue","TO BE DETERMINED")
xml.UpdateAttrAt("DocumentList|Document|FileSignatureList",True,"filesNumber","1")
xml.UpdateAttrAt("DocumentList|Document|FileSignatureList|Packaging|SplitZip",True,"mode","zip")
xml.UpdateAttrAt("DocumentList|Document|FileSignatureList|Packaging|SplitZip",True,"type","split")
xml.UpdateAttrAt("DocumentList|Document|FileSignatureList|Encryption|AES",True,"block","16")
xml.UpdateAttrAt("DocumentList|Document|FileSignatureList|Encryption|AES",True,"mode","CBC")
xml.UpdateAttrAt("DocumentList|Document|FileSignatureList|Encryption|AES",True,"padding","PKCS#7")
xml.UpdateAttrAt("DocumentList|Document|FileSignatureList|Encryption|AES",True,"size","256")
xml.UpdateAttrAt("DocumentList|Document|FileSignatureList|Encryption|AES|IV",True,"bytes","16")
xml.UpdateAttrAt("DocumentList|Document|FileSignatureList|Encryption|AES|IV",True,"encoding","Base64")
xml.UpdateChildContent("DocumentList|Document|FileSignatureList|Encryption|AES|IV","TO BE DETERMINED")
xml.UpdateChildContent("DocumentList|Document|FileSignatureList|FileSignature|OrdinalNumber","1")
xml.UpdateChildContent("DocumentList|Document|FileSignatureList|FileSignature|FileName","JPK_VAT_3_v1-1_20181201-000.xml.zip.aes")
xml.UpdateChildContent("DocumentList|Document|FileSignatureList|FileSignature|ContentLength","9999")
xml.UpdateAttrAt("DocumentList|Document|FileSignatureList|FileSignature|HashValue",True,"algorithm","MD5")
xml.UpdateAttrAt("DocumentList|Document|FileSignatureList|FileSignature|HashValue",True,"encoding","Base64")
xml.UpdateChildContent("DocumentList|Document|FileSignatureList|FileSignature|HashValue","TO BE DETERMINED")

' ------------------------------------------------------------
' Step 1: Load our JPK_VAT XML and update the DocumentList|Document|HashValue
' and DocumentList|Document|ContentLength
Dim bdXml As New Chilkat.BinData
success = bdXml.LoadFile("qa_data/xml_dsig/jpk_vat/JPK_VAT_3_v1-1_20181201-000.xml")
If (success <> True) Then
    Debug.WriteLine("Failed to load XML file.")
    Exit Sub
End If


xml.UpdateChildContentInt("DocumentList|Document|ContentLength",bdXml.NumBytes)

Dim crypt As New Chilkat.Crypt2
crypt.HashAlgorithm = "sha256"
crypt.EncodingMode = "base64"
xml.UpdateChildContent("DocumentList|Document|HashValue",crypt.HashBdENC(bdXml))

' ------------------------------------------------------------
' Step 2: Create a Zip archive containing the XML.
Dim zip As New Chilkat.Zip
' The filename we pass here doesn't matter because we won't actually be creating a .zip file.
zip.NewZip("anything.zip")
Dim e As Chilkat.ZipEntry = zip.AppendBd("JPK_VAT_3_v1-1_20181201-000.xml",bdXml)

' Write the .zip file to a BinData object.
Dim bdZip As New Chilkat.BinData
zip.WriteBd(bdZip)

' ------------------------------------------------------------
' Step 3: Generate a random 256-bit AES key (32-bytes)
Dim prng As New Chilkat.Prng
Dim bdAesKey As New Chilkat.BinData
prng.GenRandomBd(32,bdAesKey)
Dim ivBytes As String = prng.GenRandom(16,"base64")

' Store the IV (base64 string) in the XML.
xml.UpdateChildContent("DocumentList|Document|FileSignatureList|Encryption|AES|IV",ivBytes)

' ------------------------------------------------------------
' Step 4: AES encrypt our zip archive (the contents of bdZip)
crypt.CipherMode = "cbc"
crypt.KeyLength = 256
crypt.CryptAlgorithm = "aes"
crypt.PaddingScheme = 0
crypt.SetEncodedIV(ivBytes,"base64")
crypt.SetEncodedKey(bdAesKey.GetEncoded("base64"),"base64")
' AES by definition has a block size of 16.
crypt.EncryptBd(bdZip)

' bdZip now contains the AES encrypted data. 
' Note: This is NOT the same as a zip where the contents are AES encrypted.
' In that case, we have an unencrypted zip structure with AES encrypted files within.
' In our case, the entire zip file image is encrypted.

' Save the bdZip to a file.  This is what will get sent to e-dokumenty.mf.gov.pl
success = bdZip.WriteFile("qa_output/JPK_VAT_3_v1-1_20181201-000.xml.zip.aes")
xml.UpdateChildContentInt("DocumentList|Document|FileSignatureList|FileSignature|ContentLength",bdZip.NumBytes)

' ------------------------------------------------------------
' Step 4: RSA Encrypt the AES key using the public key certificate provided by the Ministry of Finance
Dim cert As New Chilkat.Cert
success = cert.LoadFromFile("qa_data/pem/mf_public_rsa.pem")
If (success = False) Then
    Debug.WriteLine(cert.LastErrorText)
    Exit Sub
End If


Dim pubKey As Chilkat.PublicKey = cert.ExportPublicKey()
Dim rsa As New Chilkat.Rsa
rsa.UsePublicKey(pubKey)


rsa.EncodingMode = "base64"
rsa.LittleEndian = False
' in-place RSA encrypt the contents of bdAesKey.
rsa.EncryptBd(bdAesKey,False)
xml.UpdateChildContent("EncryptionKey",bdAesKey.GetEncoded("base64"))

' Step 5: We forgot to get the MD5 hash of the AES encrypted zip.
' (I'm assuming we need the MD5 of the encrypted zip as opposed to the MD5 of the pre-encrypted zip..)
crypt.HashAlgorithm = "md5"
xml.UpdateChildContent("DocumentList|Document|FileSignatureList|FileSignature|HashValue",crypt.HashBdENC(bdZip))

' At this point, the XML is prepared and the AES encrypted image of the zip file is written
' to a file (and also in bdZip).
Dim finalXml As String = xml.GetXml()
Debug.WriteLine(finalXml)

xml.SaveXml("qa_output/jpk_vat.xml")

Debug.WriteLine("Finished.")