(C#) Create JPK VAT metadata XML

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

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// 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>

bool success;
Chilkat.Xml xml = 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
Chilkat.BinData bdXml = new Chilkat.BinData();
success = bdXml.LoadFile("qa_data/xml_dsig/jpk_vat/JPK_VAT_3_v1-1_20181201-000.xml");
if (success != true) {
    Debug.WriteLine("Failed to load XML file.");
    return;
}

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

Chilkat.Crypt2 crypt = 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.
Chilkat.Zip zip = 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");
Chilkat.ZipEntry e = zip.AppendBd("JPK_VAT_3_v1-1_20181201-000.xml",bdXml);

// Write the .zip file to a BinData object.
Chilkat.BinData bdZip = new Chilkat.BinData();
zip.WriteBd(bdZip);

// ------------------------------------------------------------
// Step 3: Generate a random 256-bit AES key (32-bytes)
Chilkat.Prng prng = new Chilkat.Prng();
Chilkat.BinData bdAesKey = new Chilkat.BinData();
prng.GenRandomBd(32,bdAesKey);
string ivBytes = 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
Chilkat.Cert cert = new Chilkat.Cert();
success = cert.LoadFromFile("qa_data/pem/mf_public_rsa.pem");
if (success != true) {
    Debug.WriteLine(cert.LastErrorText);
    return;
}

Chilkat.PublicKey pubKey = cert.ExportPublicKey();
Chilkat.Rsa rsa = new Chilkat.Rsa();
rsa.ImportPublicKeyObj(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).
string finalXml = xml.GetXml();
Debug.WriteLine(finalXml);

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

Debug.WriteLine("Finished.");