Imagine you’re the new manager of a large apartment building and someone has stolen one of your keys—but you’re not sure which one. Was it to a first-floor apartment? The mail room? Maybe it’s a master key to all the units.Imagine you’re the new manager of a large apartment building and someone has stolen one of your keys—but you’re not sure which one. Was it to a first-floor apartment? The mail room? Maybe it’s a master key to all the units.Security[#item_full_content]