The Secret Life of Keys: On the Calculation of Mechanical Lock Systems

Abstract

Keys and locks are an omnipresent fixture in our daily life, limiting physical access to privileged resources or spaces. While most of us may have marveled at the intricate shape of a key, the usually hidden mechanical complexity within a cylinder lock is even more awe-inspiring, containing a multitude of tiny movable parts such as springs and pins that have been precision-manufactured from highly customized materials using specialized fabrication techniques. \indent It is perhaps unknown that mechanical cylinder locks possess a number of important design constraints that uniquely distinguish them from their electronic counterparts. Aside from manufacturing costs, a cylinder's most significant limitations are the upper bound on its outer dimensions as well as the lower bound on the size of its internal mechanical security features (pins). Cylinders cannot be very large so that they still fit into doors and avoid the need for large keys. Pins cannot be too small in order to withstand wear and tear and prov...