(MFC) Get Certificate Authority Information Access

Demonstrates how to get a certificate's Authority Information Access extension data (if it exists).

Note: This example requires Chilkat v9.5.0.76 or greater.

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

See Also: Using MFC CString in Chilkat

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

void ChilkatSample(void)
    {
    CkString strOut;

    CkCert cert;

    bool success = cert.LoadFromFile("qa_data/certs/test_haswdt.cer");
    if (success != true) {
        strOut.append(cert.lastErrorText());
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    //  Get the Authority Information Access extension, which is at OID 1.3.6.1.5.5.7.1.1
    const char *extensionXmlStr = cert.getExtensionAsXml("1.3.6.1.5.5.7.1.1");
    if (cert.get_LastMethodSuccess() == false) {
        strOut.append("Certificate does not have the AuthInfoAccess extension.");
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    CkXml xml;
    xml.LoadXml(extensionXmlStr);

    //  See what we have..
    strOut.append(xml.getXml());
    strOut.append("\r\n");

    //  We should get XML like this:

    //  <?xml version="1.0" encoding="utf-8" ?>
    //  <sequence>
    //      <sequence>
    //          <oid>1.3.6.1.5.5.7.48.2</oid>
    //          <contextSpecific tag="6" constructed="0">aHR0cDovL2NydC5jb21vZG9jYS5jb20vQ09NT0RPUlNBQ2xpZW50QXV0aGVudGljYXRpb25hbmRTZWN1
    //  cmVFbWFpbENBLmNydA==</contextSpecific>
    //      </sequence>
    //      <sequence>
    //          <oid>1.3.6.1.5.5.7.48.1</oid>
    //          <contextSpecific tag="6" constructed="0">aHR0cDovL29jc3AuY29tb2RvY2EuY29t</contextSpecific>
    //      </sequence>
    //  </sequence>

    //  Typically, a certificate AIA(Authority Information access) contains 2 parts:
    // 
    //      On-line Certificate Status Protocol (1.3.6.1.5.5.7.48.1)
    //      Certification Authority Issuer (1.3.6.1.5.5.7.48.2)
    // 
    //  The base64 content for each OID (in this case) is just a string.
    //  The data can be accessed and decoded like this:

    CkStringBuilder sbOcsp;
    success = xml.GetChildContentSb("/C/oid,1.3.6.1.5.5.7.48.1|++",sbOcsp);
    if (success == true) {
        sbOcsp.Decode("base64","utf-8");
        strOut.append("1.3.6.1.5.5.7.48.1:  ");
        strOut.append(sbOcsp.getAsString());
        strOut.append("\r\n");
    }

    CkStringBuilder sbIssuer;
    success = xml.GetChildContentSb("/C/oid,1.3.6.1.5.5.7.48.2|++",sbIssuer);
    if (success == true) {
        sbIssuer.Decode("base64","utf-8");
        strOut.append("1.3.6.1.5.5.7.48.2:  ");
        strOut.append(sbIssuer.getAsString());
        strOut.append("\r\n");
    }

    //  The output looks like this:

    //  1.3.6.1.5.5.7.48.1:  http://ocsp.comodoca.com
    //  1.3.6.1.5.5.7.48.2:  http://crt.comodoca.com/COMODORSAClientAuthenticationandSecureEmailCA.crt

    //  -------------------------------------------------------------------------------
    //  Note: The Chilkat path passed to GetChildContentSb is composed of two commands:
    //  The first command is "/C/oid,1.3.6.1.5.5.7.48.1".   It says "traverse the XML tree from the caller
// node and stop at the 1st node having tag = "oid" and content = "1.3.6.1.5.5.7.48.1".
    //  The "|" char separates the 1st command from the 2nd.
    //  The 2nd command is "++" and says "move to the next sibling".


    SetDlgItemText(IDC_EDIT1,strOut.getUnicode());

    }