Programming an ignition key

I have a 2003 Ford escape with one working key.
I don't want to pay the dealer hundreds of dollars to be exact $500 to make me another key. I went to eBay and bought a blank key for my car I thought I could program it with an Arduino but don't know how your help would be appreciating this matter?

I went to my local locksmith and they sold me a new key and programed it for about $75 US. Try and see if you have one that can perform that service.

Hello bob5731

Do you have any type of interface specification available?

it sounds like the programming is done on the car computer ,.isnt ?
is similar to this ? How To Program A Ford Escape Remote Key Fob 2001 - 2007 - YouTube

The key has an RFID chip (or similar) and a new key is programmed in the ECU (as @osval says).
In some vehicles it is only possible with a scanner, in others also through a sequence of maneuvers.

Regards

There are videos on you tube on how to do this on the car

What made you think you could program it with an Arduino?