تشفير الصور الملونة اعتماد h على الدوال الفوضوية == Color Image Encryption Based on Chaotic Maps
Author name:
مصطفى عبد الرزاق حسين النعيمي
Supervisor name:
سعد نجم باشخ السعد
General topic:
Computer Science
Specific topic:
Computer Science
Degree:
Master
University:
Mustansiriyah University - College Of Science - Department Of Computer
Language:
English
University location:
Baghdad
First pages:
28T845 - p.pdf
Abstract:
Due to the rapid development in the field of communications and multimedia and the increasing use of the Internet, multimedia data security has become very urgent. One of the efficient techniques to achieve the multimedia data security is encryption, which prevents the unauthorized entities from accessing confidential data.In this thesis, a system is proposed to encrypt and decrypt a colored image based on chaotic maps without losing any data.The length of the secret key used to encrypt and decrypt the image is 20 numerical digits divided into four parts; these parts represent the initial conditions and the control parameters for two chaotic maps. The output of these two chaotic maps is processed to generate ten Random Ergodic Matrices (REMs) and eight Random Bit Matrices (RBMs) used for permutation and substitution purposes.The principle of the proposed system work is to convert the colored image from its three color components into two dimensional gray scale one. The gray scale image is decomposed into eight binary images. Then permutation and substitution processes are achieved through REMs and RBMs respectively. Finally, a stage for combining the eight binary matrices to one matrix and then converting it back to the three color components is implemented to form the final colored encrypted image.Several criteria to measure the encryption quality of the proposed system have been used. The results point to high robustness and resist strongly against the most known attacks with exception of differential attack. An enhancement step is added to the proposed system focusing on blending and integrating plain image data with the secret key to make it strong enough against the most known attacks especially the differential attack.The encryption quality of the proposed system is measured again using the same criteria used before the enhancement, and the results point to good robustness and strong enough against the most known attacks including the differential attack.
