Eavesdropping on GSM: state-of-affairs

In the almost 20 years since GSM was deployed several security problems have been found, both in the protocols and in the - originally secret - cryptography. However, practical exploits of these weaknesses are complicated because of all the signal processing involved and have not been seen much outside of their use by law enforcement agencies. This could change due to recently developed open-source equipment and software that can capture and digitize signals from the GSM frequencies. This might make practical attacks against GSM much simpler to perform. Indeed, several claims have recently appeared in the media on successfully eavesdropping on GSM. When looking at these claims in depth the conclusion is often that more is claimed than what they are actually capable of. However, it is undeniable that these claims herald the possibilities to eavesdrop on GSM using publicly available equipment. This paper evaluates the claims and practical possibilities when it comes to eavesdropping on GSM, using relatively cheap hardware and open source initiatives which have generated many headlines over the past year. The basis of the paper is extensive experiments with the USRP (Universal Software Radio Peripheral) and software projects for this hardware.Comment: 5th Benelux Workshop on Information and System Security (WISSec 2010), November 201

Performance evaluation of BMI resin system for thin-ply composites

Composites materials are increasingly being used in aerospace applications over the past few years. The unique properties like high strength to weight ratio, thermal stability, fatigue and corrosion resistance set them apart from the conventional materials. Composite materials are well suited for the applications where weight is the primary concern in the design. Composites structures are vulnerable to mechanical as well as thermal loadings. Transverse micro-cracking and delamination are the most common type of failures in composite materials. The thickness of the ply being used play a key role dictating the properties of the resultant composite structure. As the ply gets thinner the properties get better. Thick laminates are more susceptible to micro-cracking than thin laminates. Thereby, to manufacture laminates resistant to micro-cracking and delamination it is advised to use thinner plies. In this work, a BMI hardened prepreg system was used to prepare the laminated composites. Thin and thick ply laminates were used to make the composite panels .Mechanical testing was performed on the panels to evaluate the performance of thin-ply and thick-ply laminate system --Abstract, page iv

Trends. An Encryption Paradox: Cracking the Groupe Speciale Mobile Standard (GSM)

The author discusses the vulnerability of encryption methods used with today\u27s modern technology

Evaluation of Nanocomposites as Lightweight Electronic Enclosures for Satellites\u27 Applications

The United States military is exploring the use of nanocomposite materials for satellite structural applications. Current composite spacecraft structures are nonconductive and must have expensive shielding materials applied in order to protect the spacecraft from catastrophic damage that can be caused by electromagnetic interference (EMI) and/or electrostatic discharge (ESD) which are characteristics of the space environment. Conductive nanocomposites are being developed for spacecraft structures that will provide ESD and EMI shielding protection without the need for expensive secondary shielding materials. This thesis studied one such material consisting of M55J/RS-3 composite combined with nickel nanostrands™. Four different configurations were tested for their ultimate tensile strength (UTS) and EMI shielding properties before and after exposure to the space environment. The four configurations tested were a baseline panel consisting of M55J/RS-3 and three configurations with different layers of nickel nanostrands™ added to the control specimen: exterior, interlaminar, and mid-plane. These four were further tested for their EMI and resistivity properties before, during and after monotonic tension tests of increasing loads up to fracture. This study found that the UTS and Young’s modulus (E) do not change after exposure to the space environment, EMI shielding of the exterior specimen is 25% better than the control specimen, sheet resistance measurements show that exterior specimens are 11% better at ESD protection than the control, and failure mechanisms are the same regardless of composite configuration: The 90° plies failed first, causing delamination in the 0/90 plies leading to transverse matrix cracking and delamination in the ±45 plies resulting in ultimate failure, and in all configurations the nanostrand layers were not damaged

Experimental Reexamination of Transverse Tensile Strength for IM7/8552 Tape-Laminate Composites

Due to the observed dependence of transverse-tensile strength, YT, on test geometry and specimen size, there is no consensus regarding a test method that can uniquely measure YT. This study reexamines characterization of YT by comparing results from established flexure tests with results from a new tensile test that exhibits consistent failure in the gage region. Additionally, the effects of surface preparation and direction of transverse fracture are investigated. Results show that YT is inversely proportional to specimen volume and surface roughness, and is insensitive to direction of transverse fracture. The relationship between specimen volume and YT is adequately captured by Weibull strength-scaling theory, except at the tails of the YT distributions. However, specimens exhibited microcracking prior to failure, which violates the weak-link assumptions of the Weibull theory. These findings highlight the challenges of using deterministic YT values in progressive damage analysis

Potential Weight Benefits of IM7/8552 Hybrid Thin-Ply Composites for Aircraft Structures

Composite materials have increasingly been used for aerospace applications due to improved performance and reduced weight compared to their metallic counterparts. Inclusion of thin-ply material, plies with cured thickness half or less than standard-ply composites, have potential to improve performance and reduce structural weight further. The effect of thin-ply material on the weight of aircraft structure was investigated by examining wing cover weight reduction. To minimize the effects on manufacturing due to using thin plies, hybrid laminates were examined that used thin 45-degree plies to replace their standard-ply counterparts in laminates. Compression after impact (CAI) tests were conducted to examine the possible weight savings that could be gained by increasing the design allowables that were used to size the wing upper cover of a semi-span test article. A large increase in CAI strength was observed for quasi-isotropic hybrid laminates, whereas less improvement was seen for hard hybrid laminates such as found in the wing cover. For laminates design by CAI strength, weight savings of about 13% were found using the hybrid hard laminates compared to the standard-ply laminates. Whether similar weight savings could be expected for structure sized using tension after impact allowables will have to be investigated further. Notched specimens were tested to examine possible weight savings using hybrid laminates in regions that are sized using discrete source damage requirements. As expected, the hybrid laminate had marginal improvements over the standard-ply laminate for compression with a notch present. The hybrid laminate, however, exhibited about 20% lower strength than the standard-ply laminate counterpart for tension with a notch. The failure mode of the hybrid specimens was a brittle, self-similar crack, which differs from the standard-ply specimens that failed by significant amounts of delamination and fiber splitting. In light of the apparent reduction in notched tensile strength, additional investigation is required to assess the use of hybrid laminates for areas containing discrete source damage, and their effect on weight of such regions

Online Recharge Card Loading: A Test Case for M-banking Implementation

This paper attempts to move mobile service from information-based to transaction-hasetl This procedure solves a number of problems associated with cell plume recharge such as: network failure, recharge card fraud, and elimination of foreign exchange cost. The system involves toll-free calls to an online hank. The bank checks the status of the account and sends notification to the mobile telecom operator who immediately credits the callers account and notification sent to both the user and the bank for account reconciliation with outright elimination of the Secret PIN card(Locally produced or imported). This system requires 110 special account but the usual current or savings account in any bank mul works on the platform of the existing telephone/Mobile banking technology. This gives more ease and convenience, reduced cost of calls tmd better management of the network as well as encouraging trusted banking culture