Bizutz

Hy to everybody, Lately I've seen the movie Transporter 2 and I would like to build a project to use in my car. It goes something like this: I will put a small keyboard with a few keys (10 or more) from which I will enter a code made of 4 or 5 digits and if this code is good (the same with the one in the memory) the car's engine will start. This project is simple, for a car NOT with an board-computer. Also I want to design it arround a 8051 microcontroller, because I have to present this project to school. I have a few ideeas, but not too great, so I want to hear some. I looked on the internet but nothing interesting, at least where I looked. Please help me with some sites or schematics if you have some. Thank you very much.