Details of the chipped keys aren't easily available; but it wuould be expected that each key should include an identifier for the vehicle for which it is to work and an additional ID that indicates the specific key being used. Both codes, vehicle+key, (or an entire code specific to a single key and registered in vehicle memory) must be fed to the starting circuit in order for the car to start.

It is not easily confirmable; but it appears that it is NOT necessary that all the keys that work in a specific vehicle have the same code. You don't "duplicate" a chipped key. You get a new one and add the code for the new key to the vehicle's memory.

Quite probably, each "authorized key number" is stored in ROM in the vehicle starting circuit.

With the systems used, it appears that if one key is lost, starting using that key can be disabled without preventing the remaining key(s) from working.(?)

From the security standpoint, it would be ideal if one of the keys must be "close enough to read" for the remote-start device to work, since "having the key" is the only way the car knows that an authorized operator is the one using the starter. This requirement might exist without being noted in the instructions, but would allow you to disable the remote starter by wrapping the key in aluminum foil (or by sticking it in your ear under your hat). You should be easily able to check whether this applies to your remote starter.

As an alternative, some remote starters allow "anyone" to start the engine, but a "real key" must be inserted before the vehicle can drive away. (Most such vehicles claim that the vehicle will shut down after a short distance if "hot-wired" to start.) This method may mean that the starter device needs to know when a real key has been inserted(?) in order to "transfer" control to the vehicle, in which case the starter unit might need to know all "good key" numbers.

If the remote start device simply supplies the key code, then anyone who picks up the device can start the car. For most/many "chipped keys," any locksmith can cut the mechanical key pattern, and the "cut key" will open the doors, with or without a chip; but the chip (or at least its ID) is required to start (and run) the vehicle.

As with most newer automotive stuff, the driver is assumed to be too stupid to understand how anything works, so any useful information is withheld and available only to dealers (or to adept industiral spies who formerly worked for dealers before going to work for even better pay at the chop shops). Even Microsoft has begun to apply this philosiphy ("the user is stupid"), although one wonders why they chose to copy the auto industry as a profit model.

John