It is extraordinarily difficult to reverse engineer 4KS. Moreover, 3 separate systems guard against key tampering and illicit copying by staff, visitors or contractors.

When a user inserts their key, 2 control bars in the cylinder scan 6 curves etched into the 4KS key and bring 12 solid, springless locking pins into specific positions. An additional bottom bar checks the edge profiles of the key. The 4KS key is scanned 4 times during the unlocking action — 3 times more than other systems. Only when all of these match up does the locking plug release.