Check out the android app for Free Cisco CCNA Security practice exam here:
https://play.google.com/store/apps/details?id=com.anandsoft.ccnasecexamsim210&hl=en
and the full version here:
https://play.google.com/store/apps/details?id=com.anandsoft.ccnasecexamsim210full&hl=en
All apps available may be seen here:
https://play.google.com/store/apps/developer?id=Anand%20Software%20and%20Training&hl=en