Java

Google Authenticator Algorithm

See more Encryption Examples

Example code implementing the Google Authenticator algorithm. Chilkat2 Java

import com.chilkatsoft.chilkat2.Crypt2;

public class ChilkatExample {

    public static void main(String[] args) {
        // 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.
        Crypt2 crypt = new Crypt2();
        String otp = crypt.totp(secretBase32, "base32", "0", "", 30, 6, -1, "sha1");

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