(C# UWP/WinRT) 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 Universal Windows Platform (UWP) / WinRT Downloads Chilkat for the Universal Windows Platform (UWP)

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

Chilkat.XmlDSig dsig = new Chilkat.XmlDSig();
Chilkat.StringBuilder sbXml = new Chilkat.StringBuilder();

bool success = sbXml.LoadFile("c:/aaworkarea/elias/3/face_f09006808443a699d1b.xml","utf-8");
if (success != true) {
    Debug.WriteLine("Failed to load XML file.");
    return;
}

success = dsig.LoadSignatureSb(sbXml);
if (success != true) {
    Debug.WriteLine(dsig.LastErrorText);
    return;
}

// Get the KeyInfo XML.
Chilkat.Xml xmlKeyInfo = dsig.GetKeyInfo();
if (dsig.LastMethodSuccess != true) {
    Debug.WriteLine(dsig.LastErrorText);
    return;
}

Debug.WriteLine(xmlKeyInfo.GetXml());
Debug.WriteLine("----");

// 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>
string certBase64 = xmlKeyInfo.GetChildContent("*:X509Data|*:X509Certificate");
if (xmlKeyInfo.LastMethodSuccess != true) {
    Debug.WriteLine("No X509Certificate found in the KeyInfo.");
    return;
}

// Load a certificate object w/ the base64.
Chilkat.Cert cert = new Chilkat.Cert();
success = cert.LoadFromBase64(certBase64);
if (success != true) {
    Debug.WriteLine(cert.LastErrorText);
    return;
}

// Examine the cert..
Debug.WriteLine("SubjectDN: " + cert.SubjectDN);
Debug.WriteLine("IssuerDN: " + cert.IssuerDN);
Debug.WriteLine("SerialNumber as Decimal: " + cert.SerialDecimal);