Locks are used to prevent unauthorized entry while permitting
authorized entry. Examples include mechanical locks, magnetic locks, and
electronic locks, password checkers and similar informational authentication
devices, and time-based, use-based, environment-based, or event-based locks.
Complexity: Lock technology has been evolving for thousands of years, and
the ideas and realizations vary from the simple to the sublime. In general,
locking mechanisms can be as complex as general informational and physical