A latch not a lock. The purpose of this latch is to hold the top section of the window from falling open. A locking system needs to be applied. The windows can be pinned as shown in the diagram below, this works extremely well and multiple pin holes can be made allowing the window to be opened partially while still preventing the window from being opened enough to gain entry. Also there are key locks available for purchase at many hardware stores that mount to the window sill and hold the window closed.
Most home owners are familiar with steel back doors.
These doors, while stronger then wooden doors, often give a false appearance of being secure. There are a number of problems with these doors that can be easily corrected. As with safes, there are fire doors, and security doors. A steel fire door is simply a thin metal wrapped around a thick foam insulation. With the right tools these doors can easily be peeled apart, bent, and entry gained.