You probably don’t want the process of key programming to be simple. The simpler it is, the easier it is spoof, such that some vagabond can match the key to a car, then steal it.
The better manufacturers require explicit authorisation by a server at the company’s HQ, only available to dealers who have subscribed (think big bucks) to the licensing terms - usually that means their own franchised dealer network. It can be enhanced even further by enforcing that keys can be programmed only once.
That does not exclude the possibility that a rogue dealer might offer to program new keys for stolen cars, and get them signed by the manufacturer, but it does mean the rogue dealer would be known to the manufacturer, there is an audit trail, and so any such rogue dealer would quickly be identified and face the consequences.
I remember my mk3 cortina. I discovered it could be opened by any other Ford key, just by wiggling it a bit. I then discovered that flat wooden lollipop sticks worked too, with skilful wiggling. I prefer the modern technology.
