Abstract: Information hiding using optical processing system is becoming a new inter-discipline and receives increasing attention recently, because of the inherent advantages of the system, such as high speed and parallel processing. In the present paper, the major methods of optical information hiding, basing on the technique like random phase encoding and digital holography, are described and analyzed. Multiple and 3D information hiding are also introduced. Finally the difficulties and possible advances for further research are also pointed out in brief.

Key words: optical information hiding, optical security, information optics, information hiding