Access control and authentication refers to the various measures, either physical or electronic, designed for monitoring of people and objects, and controlling access to and preventing intrusion of any property and information. It is primarily concerned with the restriction of physical access to unauthorized people in controlled facilities. Access control and authentication systems are powerful tools used to investigate or prevent crimes that may occur in public places such as shopping malls, multiplexes, airports, banks, casinos, and ATMs. Security also incurs costs and is never completely perfect in entirely eliminating the risks.