key question

My 99 Buick has a VATS key but I don't believe GM has been using that system in like 20 years. My old 2001 Chevy also had VATS. The VATS key has a specific resistance that the vehicle needs to measure in order to start. Just wondering what GM switched to after VATS? What is it called and how...

I just bought a 2000 Bick Cenury Custo. The previous owner lost the door keys, and allways used the remote. I would like to get keys made but need to know if the door keys have the same cut as the Ignition (chip) key. The chip does not let the key go all the way the door lock. I need to know...