(MFC) 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.

Chilkat C/C++ Library Downloads MS Visual C/C++ Libs

See Also: Using MFC CString in Chilkat

#include <CkXmlDSig.h>
#include <CkStringBuilder.h>
#include <CkXml.h>
#include <CkCert.h>

void ChilkatSample(void)
    {
    CkString strOut;

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

    CkXmlDSig dsig;
    CkStringBuilder sbXml;

    bool success = sbXml.LoadFile("c:/aaworkarea/elias/3/face_f09006808443a699d1b.xml","utf-8");
    if (success != true) {
        strOut.append("Failed to load XML file.");
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    success = dsig.LoadSignatureSb(sbXml);
    if (success != true) {
        strOut.append(dsig.lastErrorText());
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    // Get the KeyInfo XML.
    CkXml *xmlKeyInfo = dsig.GetKeyInfo();
    if (dsig.get_LastMethodSuccess() != true) {
        strOut.append(dsig.lastErrorText());
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    strOut.append(xmlKeyInfo->getXml());
    strOut.append("\r\n");
    strOut.append("----");
    strOut.append("\r\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>
    const char *certBase64 = xmlKeyInfo->getChildContent("*:X509Data|*:X509Certificate");
    if (xmlKeyInfo->get_LastMethodSuccess() != true) {
        strOut.append("No X509Certificate found in the KeyInfo.");
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    // Load a certificate object w/ the base64.
    CkCert cert;
    success = cert.LoadFromBase64(certBase64);
    if (success != true) {
        strOut.append(cert.lastErrorText());
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    // Examine the cert..
    strOut.append("SubjectDN: ");
    strOut.append(cert.subjectDN());
    strOut.append("\r\n");
    strOut.append("IssuerDN: ");
    strOut.append(cert.issuerDN());
    strOut.append("\r\n");
    strOut.append("SerialNumber as Decimal: ");
    strOut.append(cert.serialDecimal());
    strOut.append("\r\n");

    delete xmlKeyInfo;


    SetDlgItemText(IDC_EDIT1,strOut.getUnicode());

    }