This document provides a review of optical encryption and decryption technologies. It summarizes several research papers on topics such as: 1) Using chaotic iris phase masks and compressed sensing for encryption and decryption based on computer-generated holography. 2) Encrypting color images using fingerprint keys and phase-shifting digital holography. 3) A hybrid encryption method combining compressive sensing, diffractive imaging, and space multiplexing to encrypt multiple images. 4) A chaos-based optical encryption method using fractional Fourier transform and DNA operations for confusion and diffusion.