Phase-conjugation cryptography using nonlinearly recorded holograms

Implementation of an all-optical cryptograph with a double- random phase coding using nonlinearly recorded holograms is considered. This implementation is based on recently discovered ability of a nonlinearly recorded hologram with the standing reference wave to self-conjugate an object beam of arbitrary completeness. It is shown, that large apertures of a quibic hologram-based phase conjugate mirror permits to overcome the main practical difficulty hindering implementation of a double-random phase coding cryptography through diminishing the information losses due to spatial- frequency filtering of the time-inverted replica of the stored memory.