Authentication iPhone App

The application I am trying to develop is a very basic authentication device for a university project. I want the application to act as a security token by performing a calculation involving the serial number and the time, to produce a key. This key will be entered along side a username and password to authenticate the login process. The system being logged in to will perform the same calculation independently. I know very little about Xcode and I will need detailed notes alongside the code. This would ideally be completed before April 5th 2011 ## Deliverables