Java

Google Authenticator Algorithm

See more Encryption Examples

Example code implementing the Google Authenticator algorithm. Java

import com.chilkatsoft.*;

public class ChilkatExample {

  static {
    try {
        System.loadLibrary("chilkat");
    } catch (UnsatisfiedLinkError e) {
      System.err.println("Native code library failed to load.\n" + e);
      System.exit(1);
    }
  }

  public static void main(String argv[])
  {
    //  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");

    System.out.println("6-digit decimal token = " + otp);
  }
}