Unicode C
Calculate HRMC IRMark

See more XML Digital Signatures Examples
Demonstrates how to calculate an IRmark for an HMRC GovTalkMessage XML document.
Chilkat Unicode C Downloads

Unicode C
#include <C_CkXmlW.h>
#include <C_CkXmlDSigW.h>
#include <C_CkCrypt2W.h>

void ChilkatSample(void)
    {
    HCkXmlW xml;
    HCkXmlDSigW xdsig;
    BOOL withComments;
    const wchar_t *canonXml;
    HCkCrypt2W crypt;
    const wchar_t *irmark;

    // 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.
    xml = CkXmlW_Create();
    CkXmlW_putTag(xml,L"GovTalkMessage");
    CkXmlW_AddAttribute(xml,L"xmlns",L"http://www.govtalk.gov.uk/CM/envelope");
    CkXmlW_UpdateAttrAt(xml,L"Body|Message",TRUE,L"xmlns",L"urn:g3.ge:dea:call:SendDocument:v1");
    CkXmlW_UpdateChildContent(xml,L"Body|Message",L"................");

    // 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>

    wprintf(L"%s\n",CkXmlW_getXml(xml));

    // Canonicalize the XML (using C14N)
    xdsig = CkXmlDSigW_Create();
    withComments = FALSE;
    canonXml = CkXmlDSigW_canonicalizeXml(xdsig,CkXmlW_getXml(xml),L"C14N",withComments);

    // Return the base64 SHA-1 HASH of the canonical XML.
    crypt = CkCrypt2W_Create();
    CkCrypt2W_putHashAlgorithm(crypt,L"sha1");
    CkCrypt2W_putEncodingMode(crypt,L"base64");
    irmark = CkCrypt2W_hashStringENC(crypt,canonXml);

    wprintf(L"IRMark = %s\n",irmark);


    CkXmlW_Dispose(xml);
    CkXmlDSigW_Dispose(xdsig);
    CkCrypt2W_Dispose(crypt);

    }