(Android™) Google Authenticator Algorithm

Example code implementing the Google Authenticator algorithm.

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

    // Generating TOTP Base32 Secret: 
    // When you enable 2FA with a TOTP-based authenticator app, Google will provide you with a QR code
    // that you can scan using the app. This QR code contains a TOTP base32 secret.
    // You can also choose to view and copy the secret manually.

    String secretBase32 = "JBSWY3DPEHPK3PXP";

    // Do the following to calculate the 6-digit decimal Google authenticator token for a base32 secret,
    // given the current system date/time.
    CkCrypt2 crypt = new CkCrypt2();
    String otp = crypt.totp(secretBase32,"base32","0","",30,6,-1,"sha1");

    Log.i(TAG, "6-digit decimal token = " + otp);

  }

  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."
  }
}