.NET Core C#

Get Certificate CRL Distribution Points

See more Certificates Examples

Demonstrates how to get a certificate's CRL Distribution Points extension data (assuming it exists). In the vast majority of cases, there will be one CRL Distribution Point.

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

.NET Core C#

bool success = false;

Chilkat.Cert cert = new Chilkat.Cert();

success = cert.LoadFromFile("qa_data/certs/test_haswdt.cer");
if (success != true) {
    Debug.WriteLine(cert.LastErrorText);
    return;
}

// Get the CRL Distribution Points extension, which is at OID 2.5.29.31
string extensionXmlStr = cert.GetExtensionAsXml("2.5.29.31");
if (cert.LastMethodSuccess == false) {
    Debug.WriteLine("Certificate does not have the CDP extension.");
    return;
}

Chilkat.Xml xml = new Chilkat.Xml();
xml.LoadXml(extensionXmlStr);

// See what we have..
Debug.WriteLine(xml.GetXml());

// We should get XML like this:

// <?xml version="1.0" encoding="utf-8" ?>
// <sequence>
//     <sequence>
//         <contextSpecific tag="0" constructed="1">
//             <contextSpecific tag="0" constructed="1">
//                 <contextSpecific tag="6" constructed="0">aHR0cDovL2NybC5jb21vZG9jYS5jb20vQ09NT0RPUlNBQ2xpZW50QXV0aGVudGljYXRpb25hbmRTZWN1
// cmVFbWFpbENBLmNybA==</contextSpecific>
//             </contextSpecific>
//         </contextSpecific>
//     </sequence>
// </sequence>
// 

// Assuming there is one CRL Distribution Point...
Chilkat.StringBuilder sbDistPoint = new Chilkat.StringBuilder();
success = xml.GetChildContentSb("sequence|contextSpecific|contextSpecific|contextSpecific",sbDistPoint);
if (success == true) {
    sbDistPoint.Decode("base64","utf-8");
    Debug.WriteLine("CRL Distribution Point:  " + sbDistPoint.GetAsString());
}

// Sample output:
// CRL Distribution Point:  http://crl.comodoca.com/COMODORSAClientAuthenticationandSecureEmailCA.crl