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Search Results: 1 - 10 of 1679 matches for " Machhout Mohsen "
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Design and Hardware Implementation of QoSS - AES Processor for Multimedia applications
Zeghid Medien,Mohsen Machhout,Belgacem Bouallegue,Lazhar Khriji
Transactions on Data Privacy , 2010,
Abstract: For real-time applications, there are several factors (time, cost, power) that are moving security considerations from a function centric perspective into a system architecture (hardware/software) design issue. Advanced Encryption Standard (AES) is used nowadays extensively in many network and multimedia applications to address security issues. The AES algorithm specifies three key sizes: 128, 192 and 256 bits offering different levels of security. To deal with the amount of application and intensive computation given by security mechanisms, we define and develop a QoSS (Quality of Security Service) model for reconfigurable AES processor. QoSS has been designed and implemented to achieve a flexible trade-off between overheads caused by security services and system performance. The proposed architecture can provide up to 12 AES block cipher schemes within a reasonable hardware cost. We envisage a security vector in a fully functional QoSS request to include levels of service for the range of security service and mechanisms. Our unified hardware can run both the original AES algorithm and the extended AES algorithm (QoSS-AES). A novel on-the-fly AES encryption/ decryption design is also proposed for 128- , 192- , and 256-bit keys. The performance of the proposed processor has been analyzed in an MPEG4 video compression standard. The results revealed that the QoSS-AES processor is well suited to provide high security communication with low latencies. In our implementation based on Xilinx Virtex FPGAs, speed/area/power results from these processors are analyzed and shown to compare favorably with other well known FPGA based implementations.
Machhout Mohsen,Guitouni Zied,Zeghid Medien,Tourki Rached
International Journal of Computer Science & Applications , 2009,
A Comparative Study of Power Consumption Models for CPA Attack
Hassen Mestiri,Noura Benhadjyoussef,Mohsen Machhout,Rached Tourki
International Journal of Computer Network and Information Security , 2013,
Abstract: Power analysis attacks are types of side channel attacks that are based on analyzing the power consumption of the cryptographic devices. Correlation power analysis is a powerful and efficient cryptanalytic technique. It exploits the linear relation between the predicted power consumption and the real power consumption of cryptographic devices in order to recover the correct key. The predicted power consumption is determined by using the appropriate consumption model. Until now, only a few models have been proposed and used.In this paper, we describe the process to conduct the CPA attack against AES on SASEBO-GII board. We present a comparison between the Hamming Distance model and the Switching Distance model, in terms of number of power traces needed to recover the correct key using these models. The global successful rate achieves 100% at 11100 power traces. The power traces needed to recover the correct key have been decreased by 12.6% using a CPA attack with Switching Distance model.
The Coordinate Ratios as a Tool to Analyze the Intrusion based on Buzek-Hillery Quantum Copying Machine
Besma Othmani,Mohsen Machhout,Houcine Mejri,Hafedh Belmabrouk
International Journal of Network Security & Its Applications , 2012,
Abstract: The intrusion based on Bu ek-Hillery universal quantum copying machine (UQCM) is investigated. A major problem to the eavesdropper Eve is how to choose the intrusion parameters required by the copying machine in order to take out the maximum of information on the transmitted qubits while making her intrusion as discrete as possible. The present paper attempts to investigate the equatorial and isotropic cloning by means of coordinate ratios. The degree of intrusion is evaluated by means of the ratios of the receiver (Bob) coordinates and the eavesdropper (Eve) coordinates to the sender (Alice) coordinates in the Bloch sphere. The fidelity has been usually used as a criterion to analyze the intrusion. More especially, this fidelity can achieve the value 0.85 for equatorial qubits by using Bu ek-Hillery 1→2 machine. Our goal is to study the behavior of these ratios as a function of the intrusion parameters. As has been found, the coordinate ratios of both the receiver and the eavesdropper achieve an optimal value higher than 2/3, in contrast to the isotropic cloning. This can favor the eavesdropping when using equatorial qubits. For isotropic cloning, the maximal intrusion is reached when the coordinate ratios are equal. The optimal values of the intrusion parameters are then evaluated.
Coupled FPGA/ASIC Implementation of Elliptic Curve Crypto-Processor
Mohsen Machhout,Zied Guitouni,Kholdoun Torki,Lazhar Khriji
International Journal of Network Security & Its Applications , 2010,
Abstract: In this paper, we propose an elliptic curve key generation processor over GF(2163) scheme based on the Montgomery scalar multiplication algorithm. The new architecture is performed using polynomial basis.The Finite Field operations use a cellular automata multiplier and Fermat algorithm for inversion. For real time implementation, the architecture has been tested on an ISE 9.1 Software using Xilinx Virtex II Pro FPGA and on an ASIC CMOS 45 nm technology as well. The proposed implementation provides a time of 2.07 ms and 38 percent of Slices in Xilinx Virtex II Pro FPGA. Such features reveal the highefficiently of this implementation design
Low Power Elliptic Curve Digital Signature Design for Constrained Devices
Elhadjyoussef Wajih,Benhadjyoussef Noura,Machhout Mohsen,Tourki Rached
International Journal of Security , 2012,
Abstract: Digital signatures represent one of the most widely used security technologies for ensuringunforgeability and non-repudiation of digital data. In this paper a reduced power dissipation ofhardware Elliptic Curve Digital Signature design has been developed.Our proposed architecture is based on the Globally Asynchronous Locally Synchronous (GALS)design methodology. In GALS system, modules that are not used frequently can be made toconsume less power by pausing their local clocks until they are needed. Our design consists ofusing units that are clocked independently. The whole ECDSA design is captured using VHDLlanguage, over the finite field GF (2163), and the Virtex IV FPGA device is used for the hardwareimplementation of the architecture.
Multiple Periodic Solutions for Some Classes of First-Order Hamiltonian Systems  [PDF]
Mohsen Timoumi
Applied Mathematics (AM) , 2011, DOI: 10.4236/am.2011.27114
Abstract: Considering a decomposition R2N=A⊕B of R2N , we prove in this work, the existence of at least (1+dimA) geometrically distinct periodic solutions for the first-order Hamiltonian system Jx'(t)+H'(t,x(t))+e(t)=0 when the Hamiltonian H(t,u+v) is periodic in (t,u) and its growth at infinity in v is at most like or faster than |v|a, 0≤a<1 , and e is a forcing term. For the proof, we use the Least Action Principle and a Generalized Saddle Point Theorem.
Corrosion effect on the flexural strength & micro-hardness of ips e-max ceramics  [PDF]
Cherif Mohsen
Open Journal of Stomatology (OJST) , 2011, DOI: 10.4236/ojst.2011.12006
Abstract: Objectives: The effect of ceramics construction (press- able, machinable) and corrosion on flexural strength and micro-hardness was studied. Materials & Methods: Two types of ceramics were tested: IPS e-max Press and IPS e-max CAD. Forty samples were constructed and divided into 2 groups according to the type of ceramics. Each group was then subdivided into 2 subgroups. Subgroups 1 were not subjected to corrosion while subgroups 2 were subjected to corro-sion test. Finally each subgroup was divided into 2 classes according to the type of test: biaxial flexural strength, micro-hardness. Results: There was a sig-nificant difference between the two tested ceramics as regard weight loss as IPS e-max CAD recorded less weight loss than IPS e-max Press. As regard the flex-ural strength, IPS e-max CAD recorded significant higher strength than IPS e-max Press. Corroded sam- ples recorded significant lower flexural strength than non-corroded samples for the two tested ceramics. As regard the Vickers micro-hardness test, the results showed significant difference between the two tested ceramics. IPS e-max CAD recorded higher mi-cro-hardness values than IPS e-max Press. The results also showed that the corroded samples recorded no significant micro-hardness values than non- corroded samples for the two tested ceramics. Conclusions: IPS e-max CAD recorded less weight loss weight loss after being subjected to corrosion test than IPS e-max Press. The method of fabrication affected the flexural strength µ-hardness of ceramic as machinable ceramic (e-max CAD) recorded significant higher data than pressable ceramic (e-mas Press). Corrosion decreased the flexural strength of both tested ceramics but had no effect on micro- hardness.
Using Intelligent Computational Methods for Optimizing Niching Method  [PDF]
Mohsen Jahanshahi
International Journal of Intelligence Science (IJIS) , 2011, DOI: 10.4236/ijis.2011.11001
Abstract: Optimization implies the minimization or maximization of an objective function. Some problems have sev-eral optimum points which all, should be computed. Niching method is presented to do so. However, its efficiency can be improved via combining it with Memetic algorithm. Therefore, in this paper, Memetic method is used to improve this method in terms of convergence rate and diversity. In the proposed methods, genetic algorithm, PSO, and learning automata are used as a local search algorithm of Memetic method. The result of simulations demonstrates that proposed methods are more effective compared with Niching in terms of convergence and diversity.
Vertical marginal gap & retention of ceramic full coverage & inlay retained ceramic fixed partial dentures  [PDF]
Cherif Mohsen
Open Journal of Stomatology (OJST) , 2011, DOI: 10.4236/ojst.2011.14021
Abstract: Objectives: A comparison study between ceramic full coverage FPDs & 3 designs of ceramic inlay retained FPDs regarding vertical marginal gap & retention. Materials & Methods: Twenty samples were construc- ted and divided into 4 groups according to the type of restorations: full coverage, inlay-shaped (occluso-pro- ximal inlay + proximal box), tub-shaped (occluso-pro- ximal inlay), and proximal box-shaped FPDs. All samples were subjected to a vertical marginal gap measurements followed by a retention test. Results: The vertical marginal gap data showed no significant difference between full coverage FPDs, the tub-shap- ed inlay retained FPDs and the proximal box-shaped inlay retained FPDs. While there was a difference between these three designs and the inlay retained FPDs. Regarding retention, the full coverage FPDs recorded higher retentive strengths and was signifi-cant difference than all inlay retained FPDs designs tested. The inlay-shaped design was significant dif-ference than the other two inlay retained FPDs de-signs. Conclusions: There was no significant differ- ence between full coverage FPDs, tub-shaped & pro- ximal box shaped inlay retained FPDs as regard ver- tical marginal discrepancies. While, the inlay-haped design showed the highest vertical marginal discrep- ancies. The premolar & molar retainers for the same type of restorations showed no difference in vertical marginal discrepancies. All measured vertical mar- ginal discrepancies were in the range of clinical ac- ceptance. The full coverage FPDs recorded higher retentive strengths than all inlay retained FPDs de- signs tested. The inlay-shaped design recorded the highest retentive strengths among the three inlay re- tained FPDs designs. There was no difference as re- gard retentive strengths between tub-shaped & pro- ximal box shaped inlay retained FPDs.
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