(Android™) Get a Certificate's Key Size

Demonstrates how to get the RSA key size of a certificate (for example, 1024-bit, 2048-bit, etc.)

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);

    //  For this example, I have a certificate in raw base64 format (not PEM),
    //  that looks like this:  "MIIGkDCCBHigAwIBAgIUMDA ... s/iqLsLA=="
    CkStringBuilder sbCertBase64 = new CkStringBuilder();
    boolean success = sbCertBase64.LoadFile("qa_data/certs/base64Cert.txt","utf-8");

    CkCert cert = new CkCert();
    success = cert.LoadFromBase64(sbCertBase64.getAsString());
    if (success != true) {
        Log.i(TAG, cert.lastErrorText());
        return;
        }

    //  Get the public key.
    CkPublicKey pubKey = cert.ExportPublicKey();
    if (cert.get_LastMethodSuccess() != true) {
        Log.i(TAG, cert.lastErrorText());
        return;
        }

    //  In Chilkat version v9.5.0.67, the KeySize property was added.
    int numBits = pubKey.get_KeySize();
    Log.i(TAG, "Number of bits = " + String.valueOf(numBits));

    //  If using an older version of Chilkat, the key size can be obtained like this:
    CkXml xml = new CkXml();
    xml.LoadXml(pubKey.getXml());

    CkBinData binDat = new CkBinData();
    binDat.AppendEncoded(xml.getChildContent("Modulus"),"base64");

    numBits = 8 * binDat.get_NumBytes();
    Log.i(TAG, "Number of bits = " + String.valueOf(numBits));


  }

  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."
  }
}