firefly-iii/app/Http/Requests/TokenFormRequest.php

<?php
declare(strict_types = 1);

namespace FireflyIII\Http\Requests;

use Auth;
use Input;

/**
 * Class TokenFormRequest
 *
 *
 * @package FireflyIII\Http\Requests
 */
class TokenFormRequest extends Request
{
    /**
     * @return bool
     */
    public function authorize()
    {
        // Only allow logged in users
        return Auth::check();
    }

    /**
     * @return array
     */
    public function rules()
    {

        $rules = [
        	'secret' => 'required',
            'code' => 'required|2faCode:secret',            
        ];

        return $rules;
    }
}