Android Home Button Disable

I need a very simple app which has the following feature : When the app is launched, the home key is disabled. That means pressing the home key does not take you to your Home launcher. You stay in the app itself. To exit the app you need to enter a password and then you are back to home screen. The HOME key should work normally when you are outside the app, but it should be disabled when you open the app. I dont need any design and stuff, just this one functionality. You can have a look at Toddler Lock app on the Android market store if you want to. It does the EXACT same thing.