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265 results on '"Zajic, Alenka"'

67. PITEM: Permutations-Based Instruction Tracking Via Electromagnetic Side-Channel Signal Analysis.

Author

Ugurlu, Elvan Mert, Yilmaz, Baki Berkay, Zajic, Alenka, and Prvulovic, Milos

Subjects
CYBER physical systems, HIERARCHICAL clustering (Cluster analysis), INDIVIDUALIZED instruction, INTERNET of things, SIGNAL-to-noise ratio
Abstract

The emergence of cyber-physical systems (CPS) and internet of things (IoT) devices impose significant security and privacy concerns that necessitate robust monitoring and malware detection systems. This paper proposes PITEM, a framework for instruction-level monitoring and malware detection using electromagnetic (EM) side-channels. PITEM identifies instruction types with similar EM emanations using hierarchical clustering. To track all combinations of these instruction types, we generate EM signatures for all permutations of them. In testing, we predict the permutation class of testing traces by a matched-filter-like predictor. We test the performance on two devices (FPGA-based and ARM-based) with 50 MHz and 1 GHz clock frequencies. We achieve 95.67 and 87.35 percent accuracies for these devices for single execution of permutations. We note that the accuracy increases to 100 percent when permutation blocks are repeated. Furthermore, we test the limits of the system by tracking permutations of instructions of the same type. With sufficient bandwidth and number of repetitions, individual instructions can be resolved with 87.5 and 95.78 percent accuracies for these devices. The performance is evaluated for different relative signal-to-noise ratio (SNR) levels and performance is stable for relative SNR values $>15$ > 15 dB. Finally, we demonstrate PITEM's ability to detect fine-grained malware with 99.89 percent accuracy. [ABSTRACT FROM AUTHOR]

Published
2022
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68. Geometric Analysis of the Doppler Frequency for General Non-Stationary 3D Mobile-to-Mobile Channels based on Prolate Spheroidal Coordinates

Author

Walter, Michael, Schmidhammer, Martin, Shutin, Dmitriy, Matolak, David, and Zajic, Alenka

Subjects
mobile-to-mobile communication, prolate spheroidal coordinate system, algebraic curve, geometry-based stochastic channel model, Nachrichtensysteme, differential forms, Doppler frequency, Institut für Kommunikation und Navigation
Abstract

Mobile-to-mobile channels often exhibit timevariant Doppler frequency shifts due to the movement of transmitter and receiver. An accurate description of the Doppler frequency turns out to be very difficult in Cartesian coordinates, and any subsequent algebraic analysis of the Doppler frequency is intractable. In contrast to other approaches, we base our investigation on a geometric description of the Doppler frequency with the following three mathematical pillars: prolate spheroidal coordinate system, algebraic curve theory, and differential forms. The prolate spheroidal coordinate system is more appropriate to algebraically investigate the problem. After the transformation into the new coordinate system, the theory of algebraic curves is needed to resolve the ambiguities. Finally, the differential forms are required to derive the joint delay Doppler probability density function. This function is normalized by the equivalent ellipsoidal area of the scattering plane bounded by the delay ellipsoid. The results generalize in a natural way our previous model to a complete 3D description. Our solutions enable insight into the geometry of the Doppler frequency and we were able to derive a Doppler frequency that is dependent on the delay and the scattering plane. The presented theory allows describing any time-variant, single-bounce, mobile-to-mobile scattering channel.

Published
2020

77. EMMA

Author

Sehatbakhsh, Nader, primary, Nazari, Alireza, additional, Khan, Haider, additional, Zajic, Alenka, additional, and Prvulovic, Milos, additional

Published
2019
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