Calculate HRMC IRMark

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Demonstrates how to calculate an IRmark for an HMRC GovTalkMessage XML document.

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

// First build a sample (but incomplete) GovTalkMessage.
// You can replace this code with a call to LoadXml or LoadXmlFile..
// 
// Note: The online tool at https://tools.chilkat.io/xmlCreate.cshtml
// can be used to generate XML code that creates a given XML document.
Chilkat.Xml xml = new Chilkat.Xml();
xml.Tag = "GovTalkMessage";
xml.AddAttribute("xmlns","http://www.govtalk.gov.uk/CM/envelope");
xml.UpdateAttrAt("Body|Message",true,"xmlns","urn:g3.ge:dea:call:SendDocument:v1");
xml.UpdateChildContent("Body|Message","................");

// This is the XML created:
// <?xml version="1.0" encoding="utf-8" ?>
// <GovTalkMessage xmlns="http://www.govtalk.gov.uk/CM/envelope">
//     <Body>
//         <Message xmlns="urn:g3.ge:dea:call:SendDocument:v1">................</Message>
//     </Body>
// </GovTalkMessage>

Debug.WriteLine(xml.GetXml());

// Canonicalize the XML (using C14N)
Chilkat.XmlDSig xdsig = new Chilkat.XmlDSig();
bool withComments = false;
string canonXml = xdsig.CanonicalizeXml(xml.GetXml(),"C14N",withComments);

// Return the base64 SHA-1 HASH of the canonical XML.
Chilkat.Crypt2 crypt = new Chilkat.Crypt2();
crypt.HashAlgorithm = "sha1";
crypt.EncodingMode = "base64";
string irmark = crypt.HashStringENC(canonXml);

Debug.WriteLine("IRMark = " + irmark);