Cryptanalysis of an Efficient Signcryption Scheme with Forward Secrecy Based on Elliptic Curve

The signcryption is a relatively new cryptographic technique that is supposed to fulfill the functionalities of encryption and digital signature in a single logical step. Several signcryption schemes are proposed throughout the years, each of them having its own problems and limitations. In this paper, the security of a recent signcryption scheme, i.e. Hwang et al.'s scheme is analyzed, and it is proved that it involves several security flaws and shortcomings. Several devastating attacks are also introduced to the mentioned scheme whereby it fails all the desired and essential security attributes of a signcryption scheme.Comment: 5 Pages, 2 Figure

LPKI - A Lightweight Public Key Infrastructure for the Mobile Environments

The non-repudiation as an essential requirement of many applications can be provided by the asymmetric key model. With the evolution of new applications such as mobile commerce, it is essential to provide secure and efficient solutions for the mobile environments. The traditional public key cryptography involves huge computational costs and is not so suitable for the resource-constrained platforms. The elliptic curve-based approaches as the newer solutions require certain considerations that are not taken into account in the traditional public key infrastructures. The main contribution of this paper is to introduce a Lightweight Public Key Infrastructure (LPKI) for the constrained platforms such as mobile phones. It takes advantages of elliptic curve cryptography and signcryption to decrease the computational costs and communication overheads, and adapting to the constraints. All the computational costs of required validations can be eliminated from end-entities by introduction of a validation authority to the introduced infrastructure and delegating validations to such a component. LPKI is so suitable for mobile environments and for applications such as mobile commerce where the security is the great concern.Comment: 6 Pages, 6 Figure

SSMS - A Secure SMS Messaging Protocol for the M-payment Systems

The GSM network with the greatest worldwide number of users, succumbs to several security vulnerabilities. The short message service (SMS) is one of its superior and well-tried services with a global availability in the GSM networks. The main contribution of this paper is to introduce a new secure application layer protocol, called SSMS, to efficiently embed the desired security attributes in the SMS messages to be used as a secure bearer in the m-payment systems. SSMS efficiently embeds the confidentiality, integrity, authentication, and non-repudiation in the SMS messages. It provides an elliptic curve-based public key solution that uses public keys for the secret key establishment of a symmetric encryption. It also provides the attributes of public verification and forward secrecy. It efficiently makes the SMS messaging suitable for the m-payment applications where the security is the great concern.Comment: 6 Pages, 5 Figure

A new approach to content-based file type detection

File type identification and file type clustering may be difficult tasks that have an increasingly importance in the field of computer and network security. Classical methods of file type detection including considering file extensions and magic bytes can be easily spoofed. Content-based file type detection is a newer way that is taken into account recently. In this paper, a new content-based method for the purpose of file type detection and file type clustering is proposed that is based on the PCA and neural networks. The proposed method has a good accuracy and is fast enough.Comment: 6 Pages, 5 Figure, 2 Table

The comparison of heavy metals Hg, Cd and Pb in the tissues of Liza abu from Karoon and Bahmanshir Rivers, Khuzestan Province

A comparative study was conducted on concentration of heavy metals Hg, Cd and Pb in the muscle, liver and gill tissues of Liza abu in winter 2009, in Karoon and Bahmanshir Rivers of Khuzestan province. We used 216 specimens of Liza abu. Metals were extracted from the tissues using wet digestion method and concentration of the heavy metals was measured by Atomic Absorption Spectrophotometer. The highest concentration of Cd, Hg and Pb were measured at 0.540±0.264, 0.029±0.005 and 1.080±0.128mg/Kg dry weight respectively. The lowest concentration of Cd, Hg and Pb were found to be 0.434±0.035, 0.024±0.001 and 0.930±0.036mg/Kg dry weight, respectively. No significant differences in concentration of heavy metals Cd, Hg and Pb in the muscle, liver and gill of Liza abu from the Karoon and Bahmanshir Rivers were detected (P 0.05). Results showed accumulation of Hg and Cd was lower than the FDA standard but accumulation of Pb was higher than the WHO standard

Radicular cyst associated with a primary first molar: A case report

Radicular cysts arising from deciduous teeth are rare. This report presents a case of radicular cyst associated with a primary molar following pulp therapy and discusses the relationship between pulp therapy and the rapid growth of the cyst. The treatment consisted of enucleation of the cyst sac and extraction of the involved primary teeth and 20 months follow up of the patient. Early diagnosis of the lesion would have lead to a less aggressive treatment plan

Effects of window position on natural cross ventilation in vernacular architecture of mazandaran (case study: SARI)

Among the most effective architectures is vernacular architecture of Mazandaran whose incorporation in nature is so delicate that appears to be an essential part of it. Paying more attention to vernacular architecture and promoting it can be helpful in reducing energy consumption. Increasing use of fossil fuels in heating and cooling systems of buildings that come with excessive costs can result from inattention to vernacular architecture principles. However taking them into consideration can be an effective solution for reducing energy consumption. This research aimed to study the effects of window position on natural cross ventilation in Vernacular architecture of Mazandaran applying Descriptive - analytical approach. For this reason, a number of vernacular buildings, located in Sari, were studied regarding numbers and sizes of bilateral opening and its function in ventilation. Variables in this research were tested using SPSS and Regression correlation coefficient; additionally, all 3 formulas suggested in the results were evaluated to achieve an optimal model. In this study, for a desirable ventilator, for every percent added to the room area, the windows showed a 0.87 percent increase in size, and for every additional story, the optimal ventilation grew 30 percent. On the other hand, in high-rise apartments, the protrusion contribution in ventilation system was highlighted. This research study aims to clarify the principles of proper ventilation in vernacular architecture which have long been forgotten. Keywords: natural ventilation; window; vernacular architecture; temperate and wet climate

Distributed control strategy for DC microgrids based on average consensus and fractional-order local controllers

A novel distributed secondary layer control strategy based on average consensus and fractional-order proportional-integral (FOPI) local controllers is proposed for the regulation of the bus voltages and energy level balancing of the energy storage systems (ESSs) in DC microgrids. The distributed consensus protocol works based on an undirected sparse communication network. Fractional-order local controllers increase the degree of freedom in the tuning of closed-loop controllers, which is required for DC microgrids with high order dynamics. Therefore, here, FOPI local controllers are proposed for enhanced energy balancing of ESSs and improved regulation of the bus voltages across the microgrid. The proposed control strategy operates in both islanded and grid-connected modes of a DC microgrid. In both modes, the average voltage of the microgrid converges to the microgrid desired reference voltage. The charging/discharging of ESSs is controlled independent of the microgrid operating mode to maintain a balanced energy level. The performance of the proposed distributed control strategy is validated in a 38- V DC microgrid case study, simulated by Simulink real-time desktop, consisting of 10 buses and a photovoltaic renewable energy source