Ptychographic attack on the double random amplitude-phase optical encoding system

Double random amplitude-phase encoding (DRAPE) system is immune to the conventional phase retrieval attack. Here, we demonstrate that the DRAPE system is vulnerable to the ptychographic phase retrieval method. By using the ptychographic attack algorithm, the keys of DRAPE system can be cracked. Moreover, since the question of the optical cryptanalysis can be transformed into a problem of ptychography imaging system, the ptychographic attack may further promoted to other the optical image cryptosystems.