A key cutting machine is the one that makes copies of keys: it holds the original key and a key blank in two vices and, while a tracer runs along the profile of the original, a cutter shapes the new one to the same form.
There are machines for flat cut keys, for dimple keys and for other profiles. Keys for security cylinders usually have protected profiles and in many cases can only be copied on presentation of a key card.
At Cerrajero Torrevieja we do not cut copies of keys. If what worries you is that there are copies of your key out there, because you have bought the property or the tenant has changed, what solves the problem is changing the cylinder. See cylinder replacement.