I've seen a couple of threads regarding the use of login screens but just doesn't require what I need. When my application first launches the login screen is present, they enter in the username/password and is verified on the server. If successful they can go to other sections of the application. As this application contains confidential documents, every time the application goes to sleep or the home button is pressed and upon re-entry I show a UIAlertView to confirm their password.
What I would prefer is that when the application goes to sleep the UIAlertView is shown so I'll leave it as is but when the home button is pressed, I want to force them to go back to the original login screen. I've been playing with the exit(0) but apple strongly advise against that but it forces the application to exit and then when the application opens again the login screen is displayed. I'm try to replicate this functionality without the exit(0).
Terminating your app is probably not the right approach. Consider: How do I programmatically quit my iPhone application?.
There is no API provided for gracefully terminating an iPhone application. Under the iPhone OS, the user presses the Home button to close applications. Should your application have conditions in which it cannot provide its intended function, the recommended approach is to display an alert for the user that indicates the nature of the problem and possible actions the user could take - turning on WiFi, enabling Location Services, etc. Allow the user to terminate the application at their own discretion.
You should reconsider your first approach with the UIAlertView if the use of login screens doesn't meet your needs.