(C) Create XML Digital Signature using HMAC Key

Demonstrates how to create an XML digital signature using an HMAC key.

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#include <C_CkHttp.h>
#include <C_CkStringBuilder.h>
#include <C_CkXmlDSigGen.h>

void ChilkatSample(void)
    {
    const char *url;
    HCkHttp http;
    HCkStringBuilder sbXml;
    BOOL success;
    HCkXmlDSigGen xmlSigGen;

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

    // Signs the following XML using an HMAC key.

    // <?xml version="1.0" encoding="UTF-8" standalone="no"?>
    // <collection Id="root">
    // 	<album>
    // 		<title>Questions, unanswered</title>
    // 		<artist>Steve and the flubberblubs</artist>
    // 		<year>1989</year>
    // 		<t:tracks xmlns:t="http://test.xades4j/tracks">
    // 			<t:song length="4:05" tracknumber="1">
    // 				<t:title>What do you know?</t:title>
    // 				<t:artist>Steve and the flubberblubs</t:artist>
    // 				<t:lastplayed>2006-10-17-08:31</t:lastplayed>
    // 			</t:song>
    // 			<t:song length="3:45" tracknumber="2">
    // 				<t:title>Who do you know?</t:title>
    // 				<t:artist>Steve and the flubberblubs</t:artist>
    // 				<t:lastplayed>2006-10-17-08:35</t:lastplayed>
    // 			</t:song>
    // 			<t:song length="5:14" tracknumber="3">
    // 				<t:title>When do you know?</t:title>
    // 				<t:artist>Steve and the flubberblubs</t:artist>
    // 				<t:lastplayed>2006-10-17-08:39</t:lastplayed>
    // 			</t:song>
    // 			<t:song length="4:19" tracknumber="4">
    // 				<t:title>Do you know?</t:title>
    // 				<t:artist>Steve and the flubberblubs</t:artist>
    // 				<t:lastplayed>2006-10-17-08:44</t:lastplayed>
    // 			</t:song>
    // 		</t:tracks>
    // 	</album>
    // </collection>
    // 

    // The above XML is available at https://www.chilkatsoft.com/exampleData/flubberblub.xml
    // Fetch the XML and then sign it..

    url = "https://www.chilkatsoft.com/exampleData/flubberblub.xml";
    http = CkHttp_Create();
    sbXml = CkStringBuilder_Create();
    success = CkHttp_QuickGetSb(http,url,sbXml);
    if (success != TRUE) {
        printf("%s\n",CkHttp_lastErrorText(http));
        CkHttp_Dispose(http);
        CkStringBuilder_Dispose(sbXml);
        return;
    }

    xmlSigGen = CkXmlDSigGen_Create();

    // The Signature will be inserted under the "collection" element.
    CkXmlDSigGen_putSigLocation(xmlSigGen,"collection");

    // Sign everything in <collection Id="root"> ... </collection>
    CkXmlDSigGen_AddSameDocRef(xmlSigGen,"root","sha256","C14N","","");

    // Specify the HMAC key.
    // For example, if the HMAC key is to be the us-ascii bytes of the string "secret",
    // the HMAC key can be set in any of the following ways (and also more ways not shown here..)
    CkXmlDSigGen_SetHmacKey(xmlSigGen,"secret","ascii");
    // or
    CkXmlDSigGen_SetHmacKey(xmlSigGen,"c2VjcmV0","base64");
    // or
    CkXmlDSigGen_SetHmacKey(xmlSigGen,"736563726574","hex");

    // Sign the XML..
    success = CkXmlDSigGen_CreateXmlDSigSb(xmlSigGen,sbXml);
    if (success != TRUE) {
        printf("%s\n",CkXmlDSigGen_lastErrorText(xmlSigGen));
        CkHttp_Dispose(http);
        CkStringBuilder_Dispose(sbXml);
        CkXmlDSigGen_Dispose(xmlSigGen);
        return;
    }

    // Examine the signed XML:
    printf("%s\n",CkStringBuilder_getAsString(sbXml));

    // The output is:
    // 
    // <?xml version="1.0" encoding="UTF-8" standalone="no"?>
    // <collection Id="root">
    // 	<album>
    // 		<title>Questions, unanswered</title>
    // 		<artist>Steve and the flubberblubs</artist>
    // 		<year>1989</year>
    // 		<t:tracks xmlns:t="http://test.xades4j/tracks">
    // 			<t:song length="4:05" tracknumber="1">
    // 				<t:title>What do you know?</t:title>
    // 				<t:artist>Steve and the flubberblubs</t:artist>
    // 				<t:lastplayed>2006-10-17-08:31</t:lastplayed>
    // 			</t:song>
    // 			<t:song length="3:45" tracknumber="2">
    // 				<t:title>Who do you know?</t:title>
    // 				<t:artist>Steve and the flubberblubs</t:artist>
    // 				<t:lastplayed>2006-10-17-08:35</t:lastplayed>
    // 			</t:song>
    // 			<t:song length="5:14" tracknumber="3">
    // 				<t:title>When do you know?</t:title>
    // 				<t:artist>Steve and the flubberblubs</t:artist>
    // 				<t:lastplayed>2006-10-17-08:39</t:lastplayed>
    // 			</t:song>
    // 			<t:song length="4:19" tracknumber="4">
    // 				<t:title>Do you know?</t:title>
    // 				<t:artist>Steve and the flubberblubs</t:artist>
    // 				<t:lastplayed>2006-10-17-08:44</t:lastplayed>
    // 			</t:song>
    // 		</t:tracks>
    // 	</album>
    // <ds:Signature xmlns:ds="http://www.w3.org/2000/09/xmldsig#"><ds:SignedInfo><ds:CanonicalizationMethod Algorithm="http://www.w3.org/2001/10/xml-exc-c14n#"/><ds:SignatureMethod Algorithm="http://www.w3.org/2001/04/xmldsig-more#hmac-sha256"/><ds:Reference URI="#root"><ds:Transforms><ds:Transform Algorithm="http://www.w3.org/2000/09/xmldsig#enveloped-signature"/></ds:Transforms><ds:DigestMethod Algorithm="http://www.w3.org/2001/04/xmlenc#sha256"/><ds:DigestValue>rD/g8soqKz8EiPUBhEWfcQacS0ta4ULHX3dKMEH6ZoQ=</ds:DigestValue></ds:Reference></ds:SignedInfo><ds:SignatureValue>R8dXP95VRYJBfL6d0Peogybdk27+R+JIfX8jnVu0NOI=</ds:SignatureValue></ds:Signature></collection>
    // 


    CkHttp_Dispose(http);
    CkStringBuilder_Dispose(sbXml);
    CkXmlDSigGen_Dispose(xmlSigGen);

    }