How to run code after user unlocks screen?

Mar 17 2014 5:09 AM

Am working on a new project and I would like to know, if possible, how to run code immediately after a user unlocks their windows phone screen such that my app will present them with a question which if answered correctly unlocks the phone; hence the user can access the phone as normal. If the user answers incorrectly the app persists until the user answers correctly. (Kind of a security app)