Cryptanalysis and improvement of ‘a robust smart‐card‐based remote user password authentication scheme’

With the use of smart card in user authentication mechanisms, the concept of two‐factor authentication came into existence. This was a forward move towards more secure and reliable user authentication systems. It elevated the security level by requiring a user to possess something in addition to know something. In 2010, Sood et al. and Song independently examined a smart‐card‐based authentication scheme proposed by Xu et al. They showed that in the scheme of Xu et al., an internal user of the system can turn hostile to impersonate other users of the system. Both of them also proposed schemes to improve the scheme of Xu et al. Recently, Chen et al. identified some security problems in the improved schemes proposed by Sood et al. and Song. To fix these problems, Chen et al. presented another scheme, which they claimed to provide mutual authentication and withstand lost smart card attack. Undoubtedly, in their scheme, a user can also verify the legitimacy of server, but we find that the scheme fails to resist impersonation attacks and privileged insider attack. We also show that the scheme does not provide important features such as user anonymity, confidentiality to air messages, and revocation of lost/stolen smart card. Besides, the scheme defies the very purpose of two‐factor security. Furthermore, an attacker can guess a user's password from his or her lost/stolen smart card. To meet these challenges, we propose a user authentication method with user anonymity. We show through analysis and comparison that the proposed scheme exhibits enhanced efficiency in contrast to related schemes, including the scheme of Chen et al. Copyright © 2013 John Wiley & Sons, Ltd.     

Optimisation of Bacillus cereus biofilm removal in the dairy industry using an in vitro model of cleaning‐in‐place incorporating serine protease

This article addresses a major hygienic issue in the dairy industry, namely biofilm removal. Response surface methodology was deployed to optimise Bacillus cereus biofilm removal conditions using serine protease. The currently practiced alkali cleaning‐in‐place (CIP) method was also optimised, and while the optimised protease CIP resulted in complete removal of biofilm cells, the reference CIP (with alkali) resulted in a reduction of 4.08 log biofilm cells/cm² and the optimised alkali CIP resulted in a reduction of ～4.92 log biofilm cells/cm². Furthermore, the amount of the biofilm matrix removed in the optimised protease CIP was significantly higher than that of alkali CIP. It was concluded that the optimised protease CIP has better applicability.     

Possible involvement of plasmids in degradation of malathion and chlorpyriphos by Micrococcus sp

Culture is the basic method in bacteriology. It allowed the discovery of Helicobacter pylori. Problems in the culture of this fragile, slow-growing bacterium concern transport and processing in the laboratory, but they can be solved. Culture has a 100% specificity. When performed properly, it has a sensitivity in the range of the other best diagnostic methods for Helicobacter pylori. It allows strain typing and, most importantly, susceptibility testing to antibiotics, because an increased rate of acquired resistance of Helicobacter pylori is currently observed. Culture must be performed in clinical trials, at least when antibiotics, to which Helicobacter pylori may be resistant, are used. In clinical practice, culture and susceptibility testing can generally be restricted to treatment failures. However, it is important to monitor Helicobacter pylori susceptibility to antibiotics at a national or regional level in order to give recommendations for primary treatment.     

Secure Remote User Mutual Authentication Scheme with Key Agreement for Cloud Environment

Authentication schemes are widely used mechanisms to thwart unauthorized access of resources over insecure networks. Several smart card based password authentication schemes have been proposed in the literature. In this paper, we demonstrate the security limitations of a recently proposed password based authentication scheme, and show that their scheme is still vulnerable to forgery and offline password guessing attacks and it is also unable to provide user anonymity, forward secrecy and mutual authentication. With the intention of fixing the weaknesses of that scheme, we present a secure authentication scheme. We show that the proposed scheme is invulnerable to various attacks together with attacks observed in the analyzed scheme through both rigorous formal and informal security analysis. Furthermore, the security analysis using the widely-accepted Real-Or-Random (ROR) model ensures that the proposed scheme provides the session key (SK) security. Finally, we carry out the performance evaluation of the proposed scheme and other related schemes, and the result favors that the proposed scheme provides better trade-off among security and performance as compared to other existing related schemes.

     

Unsteady laminar incompressible second-order boundary-layer flow at a three-dimensional stagnation point

Summary The unsteadely laminar incompressible second-order boundary-layer flow at the stagnation point of a three-dimensional body has been studied for both nodal and saddle point regions. The effects of mass transfer and Prandtl number have been taken into account. The equations governing the flow have been solved numerically using an implicit finite-difference scheme. It has been found that the parameter characterizing the unsteadiness in the velocity of the free stream, the nature of the stagnation point, the mass transfer and Prandtl number strongly affect the second-order skin friction and heat transfer. The overall skin friction becomes less due to second-order effects but the heat transfer has the opposite behaviour. For large injection, the second-order skin-friction and heat-transfer results prevail over the first-order boundary layer results whereas for the case of large suction the behaviour is just the opposite.With 14 Figures     

Preparation, characterization and dielectric properties of Ba3Ln3Ti5Nb5O30 (Ln=La, Nd) ceramics

Ba₃Ln₃Ti₅Nb₅O₃₀ (Ln=La, Nd) ceramics were prepared by the conventional solid-state ceramic route. The sintered samples were characterized by X-ray diffraction and scanning electron microscopy (SEM) methods. They have high dielectric constants, 141 and 203 at 13 MHz for La-based and Nd-based ceramics, respectively. The loss factor of the ceramics increases with frequency.     

Unsteady incompressible boundary layer flow of a micropolar fluid at a stagnation point

The flow, heat and mass transfer on the unsteady laminar incompressible boundary layer in micropolar fluid at the stagnation point of a 2-dimensional and an axisymmetric body have been studied when the free stream velocity and the wall temperature vary arbitrarily with time. The partial defferential equations governing the flow have been solved numerically using a quasilinear finite-difference scheme. The skin friction, microrotation gradient and heat transfer parameters are found to be strongly dependent on the coupling parameter, mass transfer and time, whereas the effect of the microrotation parameter on the skin friction and heat transfer is rather weak, but microrotation gradient is strongly affected by it. The Prandtl number and the variation of the wall temperature with time affect the heat-transfer very significantly but the skin friction and micrortation gradient are unaffected by them.