keypad code to enable ignition with relay to allow car to start.

Hey y'all this is my first project. I have the Arduino Uno. I run a Linux box on a Compaq laptop. So I have been coding in C for a few years now and just started 32bit Linux NASM a few months ago. I decided it was time to try an Arduino project. So, my project is for my truck. I have a Ford Ranger and would like to hook up a matrix keypad to the Arduino. Which would be connected to a single pole double throw relay. The relay to my ignition switch. I know the Arduino cannot power a relay. Which leads to the reason for my post; What am i in for? Is there anything else I should know, similar to the relay problem? How do i fix the relay issue? Any other thoughts?

Overall though, if i punch the correct code in, the arduino will send a pulse to the relay coil and close the circuit allowing the ignition to be started.

Don’t cross post. It just wastes everyone’s time.