Delving Deeper: Unlocking the Simplex Lock

The Simplex lock is a popular push-button combination lock found in apartment buildings, offices, schools, and other buildings. The metallic lock has five buttons that can be pushed individually or simultaneously with other buttons, and the order and number of pushes make up a unique code. Throughout this article, I use the word code rather than combination to describe a unique set of numbers to open the lock and to eliminate confusion with mathematical combinations that also appear here. The manufacturers claim that the Simplex lock can incorporate “thousands” of codes; in fact, the five-button lock can incorporate exactly 1082 codes.