…the Kaba star locking system theoretically has 18 quadrillion possible locking combinations? That’s 18,000 trillion, or 18,000,000 billion – or 18 followed by 15 zeros. So when a large operation like Zurich Airport, with thousands of locks, needs to formulate a complex locking plan, the puzzle becomes as hard as the hardest Sudoku. The art lies in finding the right permutation – calculating the possible combinations and placements for the tiny holes bored into the keys. For security reasons, Kaba only uses a fraction of the immeasurable possibilities.