(C) Examine KeyInfo Certificate in XML Signature

This example loads signed XML and gets the signing certificate, assuming the certificate is contained in X509Certificate within the KeyInfo.

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#include <C_CkXmlDSig.h>
#include <C_CkStringBuilder.h>
#include <C_CkXml.h>
#include <C_CkCert.h>

void ChilkatSample(void)
    {
    HCkXmlDSig dsig;
    HCkStringBuilder sbXml;
    BOOL success;
    HCkXml xmlKeyInfo;
    const char *certBase64;
    HCkCert cert;

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

    dsig = CkXmlDSig_Create();
    sbXml = CkStringBuilder_Create();

    success = CkStringBuilder_LoadFile(sbXml,"c:/aaworkarea/elias/3/face_f09006808443a699d1b.xml","utf-8");
    if (success != TRUE) {
        printf("Failed to load XML file.\n");
        CkXmlDSig_Dispose(dsig);
        CkStringBuilder_Dispose(sbXml);
        return;
    }

    success = CkXmlDSig_LoadSignatureSb(dsig,sbXml);
    if (success != TRUE) {
        printf("%s\n",CkXmlDSig_lastErrorText(dsig));
        CkXmlDSig_Dispose(dsig);
        CkStringBuilder_Dispose(sbXml);
        return;
    }

    // Get the KeyInfo XML.
    xmlKeyInfo = CkXmlDSig_GetKeyInfo(dsig);
    if (CkXmlDSig_getLastMethodSuccess(dsig) != TRUE) {
        printf("%s\n",CkXmlDSig_lastErrorText(dsig));
        CkXmlDSig_Dispose(dsig);
        CkStringBuilder_Dispose(sbXml);
        return;
    }

    printf("%s\n",CkXml_getXml(xmlKeyInfo));
    printf("----\n");

    // Assuming the X509Certificate is in the KeyInfo, it will look like this:

    //   <ds:KeyInfo Id="...">
    //     <ds:KeyValue>
    //     ...  
    //     <ds:X509Data>
    //       <ds:X509Certificate>MIIHAz...</ds:X509Certificate>
    //     </ds:X509Data>
    //   </ds:KeyInfo>
    certBase64 = CkXml_getChildContent(xmlKeyInfo,"*:X509Data|*:X509Certificate");
    if (CkXml_getLastMethodSuccess(xmlKeyInfo) != TRUE) {
        printf("No X509Certificate found in the KeyInfo.\n");
        CkXmlDSig_Dispose(dsig);
        CkStringBuilder_Dispose(sbXml);
        return;
    }

    // Load a certificate object w/ the base64.
    cert = CkCert_Create();
    success = CkCert_LoadFromBase64(cert,certBase64);
    if (success != TRUE) {
        printf("%s\n",CkCert_lastErrorText(cert));
        CkXmlDSig_Dispose(dsig);
        CkStringBuilder_Dispose(sbXml);
        CkCert_Dispose(cert);
        return;
    }

    // Examine the cert..
    printf("SubjectDN: %s\n",CkCert_subjectDN(cert));
    printf("IssuerDN: %s\n",CkCert_issuerDN(cert));
    printf("SerialNumber as Decimal: %s\n",CkCert_serialDecimal(cert));

    CkXml_Dispose(xmlKeyInfo);


    CkXmlDSig_Dispose(dsig);
    CkStringBuilder_Dispose(sbXml);
    CkCert_Dispose(cert);

    }