(C#) Apply 2nd Signature to sii.cl Factura Electrónica (Chile Servicio de Impuestos Internos)

Demonstrates how to apply the 2nd signature an XML invoice according to Chilean Internal Revenue Service regulations.

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

// In this example: Create sii.cl Factura Electr�nica (Chile Servicio de Impuestos Internos)
// We signed XML structured like this:

// <?xml version="1.0" encoding="iso-8859-1"?>
// <DTE version="1.0" xmlns="http://www.sii.cl/SiiDte">
//   <Documento ID="F11T22">
//     ...
//   </Documento>
// </DTE>

// To get a signature like this:
// <?xml version="1.0" encoding="iso-8859-1"?>
// <DTE version="1.0" xmlns="http://www.sii.cl/SiiDte">
//   <Documento ID="F11T22">
//     ...
//   </Documento>
//   <Signature xmlns="http://www.w3.org/2000/09/xmldsig#">
//     ..
//   </Signature>
// </DTE>

// Now we wish to wrap the result of the 1st example in the following and sign again:

// <?xml version="1.0" encoding="iso-8859-1"?>
// <EnvioDTE version="1.0" xmlns="http://www.sii.cl/SiiDte" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.sii.cl/SiiDte EnvioDTE_v10.xsd">
//     <SetDTE ID="NDTECHILE">
//         <Caratula version="1.0">
//             <RutEmisor>...</RutEmisor>
//             <RutEnvia>...</RutEnvia>
//             <RutReceptor>...</RutReceptor>
//             <FchResol>2014-08-22</FchResol>
//             <NroResol>80</NroResol>
//             <TmstFirmaEnv>2020-07-17T13:19:10</TmstFirmaEnv>
//             <SubTotDTE>
//                 <TpoDTE>34</TpoDTE>
//                 <NroDTE>1</NroDTE>
//             </SubTotDTE>
//         </Caratula>
//         <DTE version="1.0" xmlns="http://www.sii.cl/SiiDte">
//             <Documento ID="F11T22">...</Documento>
//             <Signature xmlns="http://www.w3.org/2000/09/xmldsig#">..</Signature>
//         </DTE>
//     </SetDTE>
// </EnvioDTE>

// The result will be this:

// <?xml version="1.0" encoding="iso-8859-1"?>
// <EnvioDTE version="1.0" xmlns="http://www.sii.cl/SiiDte" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.sii.cl/SiiDte EnvioDTE_v10.xsd">
//     <SetDTE ID="NDTECHILE">
//         <Caratula version="1.0">
//             <RutEmisor>...</RutEmisor>
//             <RutEnvia>...</RutEnvia>
//             <RutReceptor>...</RutReceptor>
//             <FchResol>2014-08-22</FchResol>
//             <NroResol>80</NroResol>
//             <TmstFirmaEnv>2020-07-17T13:19:10</TmstFirmaEnv>
//             <SubTotDTE>
//                 <TpoDTE>34</TpoDTE>
//                 <NroDTE>1</NroDTE>
//             </SubTotDTE>
//         </Caratula>
//         <DTE version="1.0" xmlns="http://www.sii.cl/SiiDte">
//             <Documento ID="F11T22">...</Documento>
//             <Signature xmlns="http://www.w3.org/2000/09/xmldsig#">..</Signature>
//         </DTE>
//     </SetDTE>
//     <Signature xmlns="http://www.w3.org/2000/09/xmldsig#">..</Signature>
// </EnvioDTE>

Chilkat.XmlDSigGen gen = new Chilkat.XmlDSigGen();

gen.SigLocation = "EnvioDTE";
gen.SigLocationMod = 0;
gen.SigNamespacePrefix = "";
gen.SigNamespaceUri = "http://www.w3.org/2000/09/xmldsig#";
gen.SignedInfoCanonAlg = "C14N";
gen.SignedInfoDigestMethod = "sha1";

// -------- Reference 1 --------
gen.AddSameDocRef("NDTECHILE","sha1","","","");

// Provide a certificate + private key. (PFX password is test123)
Chilkat.Cert cert = new Chilkat.Cert();
bool success = cert.LoadPfxFile("qa_data/pfx/cert_test123.pfx","test123");
if (success != true) {
    Debug.WriteLine(cert.LastErrorText);
    return;
}

gen.SetX509Cert(cert,true);

gen.KeyInfoType = "X509Data+KeyValue";
gen.X509Type = "Certificate";

// Here's the part where we must be very careful not to disturb the existing signature.
// We want to encapsulate the existing signed XML like this:

// <?xml version="1.0" encoding="iso-8859-1"?>
// <EnvioDTE version="1.0" xmlns="http://www.sii.cl/SiiDte" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.sii.cl/SiiDte EnvioDTE_v10.xsd">
//     <SetDTE ID="NDTECHILE">
//         <Caratula version="1.0">
//             <RutEmisor>...</RutEmisor>
//             <RutEnvia>...</RutEnvia>
//             <RutReceptor>...</RutReceptor>
//             <FchResol>2014-08-22</FchResol>
//             <NroResol>80</NroResol>
//             <TmstFirmaEnv>2020-07-17T13:19:10</TmstFirmaEnv>
//             <SubTotDTE>
//                 <TpoDTE>34</TpoDTE>
//                 <NroDTE>1</NroDTE>
//             </SubTotDTE>
//         </Caratula>
//         <EXISTING_SIGNED_XML>HERE</EXISTING_SIGNED_XML>
//     </SetDTE>
//     <Signature xmlns="http://www.w3.org/2000/09/xmldsig#">..</Signature>
// </EnvioDTE>

Chilkat.Xml xml = new Chilkat.Xml();
xml.Tag = "EnvioDTE";
xml.AddAttribute("version","1.0");
xml.AddAttribute("xmlns","http://www.sii.cl/SiiDte");
xml.AddAttribute("xmlns:xsi","http://www.w3.org/2001/XMLSchema-instance");
xml.AddAttribute("xsi:schemaLocation","http://www.sii.cl/SiiDte EnvioDTE_v10.xsd");
xml.UpdateAttrAt("SetDTE",true,"ID","NDTECHILE");
xml.UpdateAttrAt("SetDTE|Caratula",true,"version","1.0");
xml.UpdateChildContent("SetDTE|Caratula|RutEmisor","...");
xml.UpdateChildContent("SetDTE|Caratula|RutEnvia","...");
xml.UpdateChildContent("SetDTE|Caratula|RutReceptor","...");
xml.UpdateChildContent("SetDTE|Caratula|FchResol","2014-08-22");
xml.UpdateChildContent("SetDTE|Caratula|NroResol","80");
xml.UpdateChildContent("SetDTE|Caratula|TmstFirmaEnv","2020-07-17T13:19:10");
xml.UpdateChildContent("SetDTE|Caratula|SubTotDTE|TpoDTE","34");
xml.UpdateChildContent("SetDTE|Caratula|SubTotDTE|NroDTE","1");
xml.UpdateChildContent("SetDTE|EXISTING_SIGNED_XML","HERE");

Chilkat.StringBuilder sbXml = new Chilkat.StringBuilder();
xml.GetXmlSb(sbXml);

// Load our existing signed XML.
// We cannot load it into a Chilkat XML object because we cannot allow anything to change,
// not even indentation or whitespace.
Chilkat.StringBuilder sbExisting = new Chilkat.StringBuilder();
sbExisting.LoadFile("qa_data/xml_dsig/sii_cl/signed1.xml","iso-8859-1");

// However, we must remove the XML declarator, and we can trim the whitespace at the very front and back (i.e. whitespace completely outside the document).
int numReplaced = sbExisting.Replace("<?xml version=\"1.0\" encoding=\"iso-8859-1\"?>","");
sbExisting.Trim();

// Insert the existing signed XML into the new XML document to be signed.
numReplaced = sbXml.Replace("<EXISTING_SIGNED_XML>HERE</EXISTING_SIGNED_XML>",sbExisting.GetAsString());

// We now have the XML document ready for the 2nd signature to be applied...

// Make sure we add the "SignExistingSignatures" behavior so that this signature includes the original signature in the digest.
gen.Behaviors = "IndentedSignature,SignExistingSignatures";

// Sign the XML...
success = gen.CreateXmlDSigSb(sbXml);
if (success != true) {
    Debug.WriteLine(gen.LastErrorText);
    return;
}

// -----------------------------------------------

// Change the XML declarator to indicate iso-8859-1 (because we'll be saving using iso-8859-1)
numReplaced = sbXml.Replace("encoding=\"utf-8\"?>","encoding=\"iso-8859-1\"?>");

// Save the signed XML to a file.
success = sbXml.WriteFile("qa_data/xml_dsig/sii_cl/signed2.xml","iso-8859-1",false);

Debug.WriteLine(sbXml.GetAsString());