Ghada Zaibi

Implementation of RC5 and RC6 block ciphers on digital images

With the fast evolution of the networks technology, the security becomes an important research axis. Many types of communication require the transmission of digital images. This transmission must be safe especially in applications that require a fairly high level of security such as military applications, spying, radars, and biometrics applications. Mechanisms for authentication, confidentiality, and integrity must be implemented within their community. For this reason, several cryptographic algorithms have been developed to ensure the safety and reliability of this transmission. In this paper, we investigate the encryption efficiency of RC5 and RC6 block cipher applied to digital images by including a statistical and differential analysis then, and also we investigate those two block ciphers against errors in ambient noise. The security analysis shows that RC6 algorithm is more secure than RC5. However, using RC6 to encrypt images in rough environment (low signal to noise ratio) leads to more errors (almost double of RC5) and may increase energy consumption by retransmitting erroneous packets. A compromise security/energy must be taken into account for the good choice of encryption algorithm.

On dynamic chaotic S-BOX

The substitution table or S-Box is considered as the core of the block ciphers. The good design of the S-Box can increase the cipher security and simplicity.

A new design of dynamic S-Box based on two chaotic maps

The use of chaotic maps to construct dynamic S-Box has been increasingly studied. The aim of this paper is to propose a new design of dynamic chaotic S-Box that enhances the security criteria of the block ciphers. In fact, our S-Box is based on the combination of two chaotic maps: one and three dimensional piecewise linear maps. The randomness of these maps was verified by using the NIST test package. However, the conversion method seems to be crucial to keep the randomness and the uniformity of the binary sequences. The security analysis shows that the dynamic S-Boxes based on two chaotic maps have the lowest linear approximation probability (Lp= 0.0625), the closest value to 0.5 of the strict avalanche criteria (SAC=0.4998) and also an equiprobable input/output distribution (DF=10/256).

A novel implantable Planar Inverted-F Antenna for biomedical applications

In recent years, the Wireless Body Area Network WBAN has emerged over the world as a new technology for medical applications. The advent of technology and concern for the patients comfort lead to extreme miniaturization of medical devices. This miniaturization is not done without the degradation of the antennas performance. This paper presents a novel design of rectangular Planar Inverted-F Antenna (PIFA) for biomedical application in Medical Implantable Communications Service band MICS (402-405) MHz. The use of MICS band is of great importance. It is dedicated just for implantable medical applications thus the risk of interference is minimal. Different miniaturization techniques are combined with the use of high dielectric (substrate/superstrate) to fulfill a tradeoff between size and performances. The proposed antenna is characterized by a good performances and a small size 11.9*14.7*1.2 mm3 compared to other implantable antennas in the literature.

Parametric study on the dielectric properties of biological tissues

A good comprehensive study of the electromagnetic properties of biological layers is important since we cannot discuss an implantable antenna design without investigating the interaction of electromagnetic radiation with the tissue. The human body is not an ideal medium for the transmission of radio waves which can be considered as a barrier degrading the performance of the transmission system that uses the human body as a propagation channel. This paper deals with some notions of electromagnetic characteristics of body tissues and their dependency to the frequency.

Chaotic UWB communicatins for low rate WPAN applications

UWB technology possesses some important characteristics such as the robustness in multipath channel, the low probability of detection and interception, the relative simplicity of the systems, and the protected communication assured by UWB signals more difficult to detect that classic signals. The use of chaos for the UWB communications is put in this paper under survey with a more particular interest to the WPAN applications. The chaotic communication can answer the low complexity, to the weak power consumption and to the requirements of low cost for the application of LR-WPAN This paper describes the UWB communication with chaotic and impulses wavelets, presents differents chaotic UWB tranceveir and compare, their configurations and their propreties, and shown that the DCC-DCSK is a very promising solution for the low rate WPAN applications.

A Detuning Study of a Miniaturized PIFA Antenna inside the Human Thorax Model

Nowadays, the increasing demand for implantable medical devices (IMD) has required the design of efficient invasive antennas. However, designing an antenna operable in a biological layer is actually an extremely challenging task. The human body is not an ideal medium for the transmission of electromagnetic waves. Thus, it degrades significantly the characteristics of implantable antennas coupled with it. In this paper, the design of a miniaturized slotted rectangular Planar Inverted-F Antenna (PIFA) is proposed. The structure was first optimized to operate in the muscle layer. The location of the antenna was then varied to detect the influence of the other biological layers on its performances.

Wireless body area network for e-health applications: Overview

Today, with advances in wireless communication technologies and smart electronic sensors, a variety of e-health applications has been realized to provide efficient healthcare services. Thanks to the Wireless Body Area Network, various operations in e-health applications can be monitored. The WBAN has invaded our environment and homes because of its numerous advantages. However, the installation of the WBAN is a very challenging task because of the special characteristics of the medium under which it works. This survey paper gives an overview of WBAN in terms of its applications in the healthcare domain, its allocated frequency bands, its channel models as well as the main requirements in the design of the WBAN.

Parametric study of implantable planar inverted-F antenna for wireless body area network application

Nowadays, Implantable antenna in Wireless Body Area Networks WBAN has been a standout amongst the most creative subjects in antenna theory and design. It has emerged the world as a new technology for medical applications. Unfortunately, a number of obstacles that disrupt the communication system still need to be overcome to improve clinical applications. Further, the properties of biological tissues of the human body make it a medium with losses that affects the function of the antenna. In this paper a Planar Inverted F-Antenna PIFA with a size of 11.9*14.7*1.2 mm3 working in the Medical Implantable Communication Service MICS band is proposed. Different miniaturization techniques are combined with the use of high dielectric (substrate/superstrate) to fulfill a tradeoff between size and performances. The proposed antenna was implemented at various locations within tissue to observe its attributes and its response face to human tissue and to find the appropriate location for its operation. We have also varied the fat thickness to observe its influence in antenna characteristics.