Ibrahim F. Tarrad

Advanced Encryption Standard Algorithm: Issues and Implementation Aspects

Data encryption has become a crucial need for almost all data transaction application due to the large diversity of the remote information exchange. A huge value of sensitive data is transferred daily via different channels such as e-commerce, electronic banking and even over simple email applications. Advanced Encryption Standard (AES) algorithm has become the optimum choice for various security services in numerous applications. Therefore, many researches get focused on that algorithm in order to improve its efficiency and performance. This paper presents a survey about the cutting edge research conducted for the AES algorithm issues and aspects in terms of developments, implementations and evaluations. The contribution of this paper is targeted toward building a base for future development and implementation of the AES algorithm. It also opens door for implementing the AES algorithm using some machine learning techniques.

Performance evaluation of hybrid ACE-PTS PAPR reduction techniques

Orthogonal Frequency Division Multiplexing (OFDM) is an attractive technique for wireless communication over frequency-selective fading channels. OFDM suffers from high Peak-to-Average Power Ratio (PAPR), which limits OFDM usage and reduces the efficiency of High Power Amplifier (HPA) or badly degrades BER. Many PAPR reduction techniques have been proposed in the literature. PAPR reduction techniques can be classified into blind receiver and non-blind receiver techniques. Active Constellation Extension (ACE) is one of the best blind receiver techniques. While, Partial Transmit Sequence (PTS) can work as blind / non-blind technique. PTS has a great PAPR reduction gain on the expense of increasing computational complexity. In this paper we combine PTS with ACE in four possible ways to be suitable for blind receiver applications with better performance than conventional methods (i.e. PTS and ACE). Results show that ACE-PTS scheme is the best among others. Expectedly, any hybrid technique has computational complexity larger than that of its components. However, ACE-PTS can be used to achieve the same performance as that of PTS or worthy better, with less number of subblocks (i.e. with less computational complexity) especially in low order modulation techniques (e.g. 4-QAM and 16-QAM). Results show that ACE-PTS with V=8 can perform similar to or better than PTS with V=10 in 16-QAM or 4-QAM, respectively, with 74% and 40.5% reduction in required numbers of additions and multiplications, respectively.

Performance analysis of different opportunistic access based on secondary users priority using licensed channels in Cognitive radio networks

In Cognitive radio network, the efficiency of spectrum utilization can be improved using dynamic spectrum access. In this paper three dimension markov model with finite primary users and infinite secondary users is proposed through two different classical channel access techniques: the random channel scheme and the reservation channel scheme assignment to evaluate the impact of changing the arrival rate and service rate of the priority-based SUs on SUs blocking probability, dropping probability and hand off probability. The proposed schemes classify SUs to two classes of priority. The analytical results demonstrate that the new scheme can enhance the radio system performance.

Petri Net Reliability Models for CORBA Wireless Networks

Since the dynamic behavior of wireless networks inherits different communication patterns for the execution processes of the desired parallel tasks and the occurrence processes of handoff operations, the available reliability metrics are not applicable to study and analyze such networks. Therefore, in this paper, we propose a novel Petri net modeling methodology for accurately calculating the reliability of wireless networks that incorporate theses aspects, such as wireless CORBA network. The proposed reliability methodology is developed based on using the End-to-End Expected Instantaneous Reliability (EIR) measure. The EIR has the capability to measure the reliability of wireless networks that incorporate the handoff processes as well as the service processes. In the proposed technique, we firstly build Generalized Stochastic Petri Net (GSPN) performance model for describing the different communication pattern that can occur among the various network resources under the execution of parallel tasks. Secondly, we build GSPN performance model for describing the handoff communication processes among the various network resources. Finally, we build generic reliability model consists of the following parts: the first part describes the execution of the desired parallel tasks, the second part illustrates the mobility characteristic introduced by handoff processes, and the third part describes the dynamic behavior of failure processes of network resources. The developed model has the capability to accurately describe the occurrence of many handoff processes in CORBA network. We study and analyze the various reliability results as well as the performance results obtained from the developed GSPN models under the effect of communication distance among the CORBA network resources.

Optimized hardware implementation of the advanced encryption standard algorithm

Data encryption has become a vital need for protecting the user data in most of communication areas. Advanced Encryption Standard (AES) algorithm has become the optimum choice for various security services in numerous applications due to its reliability and flexibility. The AES algorithm faces two main challenges which included in both encryption/decryption speed, and the consumed implementation area. This paper presents an optimized implementation of the AES algorithm with respect to the consumed implementation area by combining both data and key expansion approaches. The optimized implementation of AES increases its applicability in the small sized devices such as mobile phones and smart cards. The experimental outcomes prove the superiority of the proposed optimization approach compared to the available approaches in the literature with acceptable frequency and throughput for low throughput applications.