This paper introduces a secure chaos-based model for ciphering and deciphering of digital images. The proposed approach is composed of successive confusion and diffusion stages. The confusion stage is repeated n rounds using a different key in each round. The output of the confusion stage is subjected to diffusion stage which is repeated m rounds with a different key for each round. The nested iterations in the confusion and diffusion stages with a different key for each round enlarges the key space which enhances the proposed image cryptosystem security level. A security investigation is done on a family of 2D chaotic confusion maps to select the one with highest security level to be used with the proposed image cryptosystem. The results demonstrated that the Standard map has the highest security level among the examined 2D chaotic confusion maps because it is more complicated and it has a large key space. The proposed image cryptosystem is compared to other three recent image cryptosystems using different security analysis factors including statistical tests, key space analysis, information entropy test, maximum deviation analysis, irregular deviation analysis, and avalanche effect differential analysis. The results demonstrated that, the proposed image cryptosystem with Standard map outperforms all of the other examined image encryption techniques from security point of view.

This paper presents an efficient confusion-diffusion approach for chaos-based image encryption. The proposed approach for chaos-based image cryptosystems is composed of alternative confusion and diffusion stages. A multi-dimensional chaotic map is usually employed in the confusion stage for image pixel permutation while a one-dimensional (1D) chaotic map is used for diffusion purpose. The proposed algorithm is based on two dimensional (2D) diffusion process which gives higher levels of security to the image. The security analysis of the proposed algorithm is given. The experimental results of the algorithm at different mixture of confusion and diffusion chaotic maps proof the effectiveness of the proposed cryptosystem. This mixture application of chaotic maps shows advantages of large key space and high-level security. The ciphertext generated by this cryptosystem is the same size as the plaintext size and is suitable for practical use in the secure transmission of confidential information over the Internet.

Background: Traumatic Brain Injury (TBI) is a global health problem. Preclinical trials in animals shows that early injection of progesterone after experimental TBI decreased brain edema, neuronal loss, and behavioral deficits. Erythropoietin (EPO) attenuates TBI due to its neuroprotective actions and its effect on erythropoiesis. Aim of Study: The aim of this study was to evaluate the effect of progesterone hormone versus erythropoietin on neurological outcome of patients with moderate traumatic brain injury. Material and Methods: The patients were randomly assigned to 3 equal groups (35 in each group). Group C (control): Standard care and treatment. Group P (progesterone): Standard care + progesterone 1mg/kg IM and then once/12 hours for 5 consecutive days. Group E (erythropoietin): Standard care + EPO IV 40,000IU within 6hr of the time of injury. The modified Marshall CT scan classification: Was obtained at admission and day 7. GCS: Daily evaluations over the initial 14-day period, adverse experiences, surgical procedures, intracranial complications and intake & output of fluids were recorded. Disability Rating Scale (DRS) were measured on admission and after 1 Mon., length of ICU & hospital stay and complications were measured. Results: There was statistically significant increase in GCS in group P compared to group C and E. There was statistically significant improvement in DRS in group P compared to group C and E on admission and after one month. There was statistically significant decrease in the length of ICU and hospital stay in group P compared to group C and E. Conclusion: Progesterone hormone and erythropoietin improved neurological outcome in moderate head injury patients in the form of improvement in GCS and DRS and decrease in the length of ICU and hospital stay with better outcome in progesterone in comparison with erythropoietin.