Image encryption and decryption with residual intelligibility measurements

مقدم أطروحة جامعية

Jarrar, Hashim Jamil

مشرف أطروحة جامعية

al-Sultani, Yas A.

أعضاء اللجنة

al-Ajluni, Naim M. M.
Ammar, Man
Muhammad, Sarmad B.

الجامعة

الأكاديمية العربية للعلوم المالية و المصرفية

الكلية

كلية نظم و تكنولوجيا المعلومات

القسم الأكاديمي

قسم نظم المعلومات الحاسوبية

دولة الجامعة

الأردن

الدرجة العلمية

دكتوراه

تاريخ الدرجة العلمية

2005

الملخص الإنجليزي

The use of images has increased dramatically in recent years especially with Internet applications.

When it is necessary to securely transmit data in open networks, the encryption must be performed.

Most of the cryptographic algorithms were mainly developed for text data.

Unfortunately, algorithms those are good for textual data might not suitable for multimedia data.

We tested the most known modes of encryption (ECB, CBC, CFB, and OFB) to encrypt images of different types (satellite and photo images).

Results showed that the ECB mode achieved the lowest degree of encryption with a mean entropy value of 7.78, while both of CFB and CBC modes achieved the highest degree of encryption with a mean entropy value of about 7.98 and 7.96, respectively.

The OFB mode achieved a mid-range level of encryption with a mean entropy value of 7.93.

In addition, factors that effect on encryption level were determined.

Furthermore, we proposed a new algorithm for image encryption in which a secure encryption algorithm was used to encrypt the image, suc that it is difficult to decode or predict the ciphered image to the original image.

The experimental results showed that the proposed algorithm has confusion and diffusion properties in a way that it did not contain any useful information about the plane image.

The similarity decreased to about 51 % by applying the second step of the proposed algorithm, while, the mean correlation between neighbor pixels decreased dramatically from 90 % to about 8 % by applying the third step.

The proposed algorithm has the ability to restore the original image in a 99.9 % of similarity.

I we proposed a new scheme to generate keys from the image data.

The degree of the randomness of the generated sequences was measured by using five statistical tests.

The experimental results showed that 79 % of the generated sequences passed all randomness constraints, whereas, at least 94 % of the cases passed at least four tests.

Results showed that the degree of encryption increased as the randomness level increased, especially by using the ECB mode with which the entropy value increased from 7.2 to 7.9 for different randomness level.

التخصصات الرئيسية

تكنولوجيا المعلومات وعلم الحاسوب

الموضوعات

• الكتابة
• التشفير
• الرمزية
• البيانات

عدد الصفحات

192

قائمة المحتويات

• APA
• MLA
• AMA

لغة النص

الإنجليزية

نوع البيانات

رسائل جامعية

رقم السجل

BIM-316168