The Department of Physics at the College of Science, University of Basra, discussed the doctoral thesis titled “Three-Phase Optical Encryption and Decryption Using Diffuse Representation” by graduate student Abbas Fadel Mohammed. 
The thesis aimed to study and develop advanced systems in the field of optical information security by employing modern physical and optical techniques to design highly efficient encryption systems that contribute to protecting digital data from intrusion or tampering.
The study involved the development of a set of optical encryption systems based on the integration of several advanced techniques, including phase truncation, spatial encoding, and random modulus decomposition, in addition to the use of important optical transforms such as the Fourier transform and the Fresnel transform within the encryption and decryption stages.
The results demonstrated the possibility of combining two original images into a single encrypted image, thereby reducing data redundancy and enhancing security, as well as expanding the key space by introducing additional physical parameters such as light wavelength and diffraction distances, which increases the system’s complexity and makes it more difficult to break.