Any help?

Hi everyone im looking at starting a project but im wondering about how to go about it. So what i have in mind is a 12 key matrix keypad hooked up to an arduino Uno. I was to have a 4 digit code input to turn lets say an led on, but i want it to stay on until i type the code back in and hit #. Is this very hard? Im searched but cant seem to find an example. All the help is greatly appreciated!

There is a password library in the arduino playground called "Password" try it out. Google "Arduino Password Library"

Okay ill check it out thank you, very new to Arduino still trying to learn. Appreciate the help.