Advances in optical security systems

Information security with optical means, such as double random phase encoding, has been investigated by various researchers. It has been demonstrated that optical technology possesses several unique characteristics for securing information compared with its electronic counterpart, such as many degrees of freedom. In this paper, we present a review of optical technologies for information security. Optical security systems are reviewed, and theoretical principles and implementation examples are presented to illustrate each optical security system. In addition, advantages and potential weaknesses of each optical security system are analyzed and discussed. It is expected that this review not only will provide a clear picture about current developments in optical security systems but also may shed some light on future developments.