(Android™) 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 Android™ Downloads Android™ Java Libraries Android C/C++ Libraries

// Important: Don't forget to include the call to System.loadLibrary
// as shown at the bottom of this code sample.
package com.test;

import android.app.Activity;
import com.chilkatsoft.*;

import android.widget.TextView;
import android.os.Bundle;

public class SimpleActivity extends Activity {

  private static final String TAG = "Chilkat";

  // Called when the activity is first created.
  @Override
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

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

    CkXmlDSig dsig = new CkXmlDSig();
    CkStringBuilder sbXml = new CkStringBuilder();

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

    success = dsig.LoadSignatureSb(sbXml);
    if (success != true) {
        Log.i(TAG, dsig.lastErrorText());
        return;
        }

    // Get the KeyInfo XML.
    CkXml xmlKeyInfo = dsig.GetKeyInfo();
    if (dsig.get_LastMethodSuccess() != true) {
        Log.i(TAG, dsig.lastErrorText());
        return;
        }

    Log.i(TAG, xmlKeyInfo.getXml());
    Log.i(TAG, "----");

    // 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.get_LastMethodSuccess() != true) {
        Log.i(TAG, "No X509Certificate found in the KeyInfo.");
        return;
        }

    // Load a certificate object w/ the base64.
    CkCert cert = new CkCert();
    success = cert.LoadFromBase64(certBase64);
    if (success != true) {
        Log.i(TAG, cert.lastErrorText());
        return;
        }

    // Examine the cert..
    Log.i(TAG, "SubjectDN: " + cert.subjectDN());
    Log.i(TAG, "IssuerDN: " + cert.issuerDN());
    Log.i(TAG, "SerialNumber as Decimal: " + cert.serialDecimal());


  }

  static {
      System.loadLibrary("chilkat");

      // Note: If the incorrect library name is passed to System.loadLibrary,
      // then you will see the following error message at application startup:
      //"The application <your-application-name> has stopped unexpectedly. Please try again."
  }
}