title: Captcha uses offline resources
body: <p>I want to create a CAPTCHA verification of my application, my application is developed using GWT, which not use online resources.</p>
  
  <p>I've tried with reCaptcha, but recaptcha have to access the api hosted in the google.com. Is there any ways to make it working in my local network which totally can not access any resource of the internet? thanks</p>