Open Theses

19 Entries found

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The Electrical Network Frequency describes the frequency of power lines (50Hz in Europe, 60Hz in the USA). In practice, the frequency fluctuates over time, with dips and peaks caused by the changing load situation in the network. These fluctuations have already been used in audio and video forensics to timestamp recordings. This thesis should investigate potential applications of ENF data in IT security.

Comparing Wi-Fi FullMAC and SoftMAC Implementations on the same Hardware

Bachelor Thesis, Master Thesis, Diploma Thesis, Student Research Project


In this thesis, you may interface a FullMAC Broadcom Wi-Fi chip using a SoftMAC driver to bypass the internal firmware and gain flexibility of modifying the chips behaviour. The chip may be a BCM4358 installed in Nexus 6P smartphones. Having a SoftMAC implementation, you should evaluate its performance against a FullMAC implementation by concidering processing delays and energy consumption.

Implementing an LLVM backend for Broadcom's D11 core

Bachelor Thesis, Master Thesis, Diploma Thesis, Student Research Project


Wi-Fi based Key Exchange on Android Smartphones

Bachelor Thesis, Master Thesis, Diploma Thesis, Student Research Project


TETRA Security

Bachelor Thesis, Master Thesis, Diploma Thesis


We have a basic fuzzing framework for a digital trunked radio protocol, TETRA, which is used by public services. First tests showed that devices implementing this protocol have severe security issues, for example, freezing and rebooting devices with minor packet modifications is possible. Since this technology is used by emergency services and big companies, these security issues are very critical, and hence need to be revealed and fixed.

Disruption-Tolerant Networks (DTNs) can be used as a communication means in the emergency context when communication infrastructure is unavailable. In DTNs, mobile user devices such as smartphones act as “data mules”: they store, carry and forward messages. Unfortunately, the “storing” part is especially vulnerable to denial-of-service (DoS) attacks since an attacker can flood the network with bogus information and, thus, replace or purge valid messages from a node’s buffer.

In this thesis, you will implement and evaluate a novel, DoS-resistant buffer management scheme in IBR-DTN [1], DTN implementation written in C++, which also runs on standard Android smartphones.

[1] IBR-DTN. https://github.com/ibrdtn/ibrdtn.

CSMA/CD for Wi-Fi

Master Thesis


Carrier Sense Multiple Access with Collision Detection (CSMA/CD) is a technique used in wired networks like Ethernet (IEEE 802.3) to improve network performance by efficient medium access. When a collision is detected, the colliding nodes terminate their transmissions to keep the collision time as short as possible. This effectively improves the utilization of the transmission medium, since less time is spent in collisions and the time between transmission attempts is reduced.

In wireless networks, however, CSMA/CD is generally assumed to be impractical due to the physical characteristics of the wireless channel. In fact, the power of a signal degrades by orders of magnitudes on its way from transmitter to receiver due to free space path loss and signal propagation effects, such as attenuation and reflections. Therefore, even if a transmitter was equipped with a separate receive antenna, its own transmission would typically drown out the weak signals from other transmitters, which would render the detection of weak signals impossible. Nevertheless, recent research has demonstrated that self-interference cancellation techniques become feasible, which allows to design full-duplex radios [1]. This might effectively be key to the design of CSMA/CD for IEEE 802.11-based networks, allowing for enhanced network performance under high load conditions [2].

[1] Mayank Jain, Jung Il Choi, Taemin Kim, Dinesh Bharadia, Siddharth Seth, Kannan Srinivasan, Philip Levis, Sachin Katti, and Prasun Sinha. "Practical, Real-Time, Full Duplex Wireless", 17th annual international conference on Mobile computing and networking (ACM MobiCom '11). Las Vegas, Nevada, USA, 2011, pp. 301-312.
[2] Konstantinos Voulgaris, Athanasios Gkelias, Imran Ashraf, Mischa Dohler and A. H. Aghvami. "Throughput Analysis of Wireless CSMA/CD for a Finite User Population", IEEE Vehicular Technology Conference, Montreal, Quebec, CA, 2006, pp. 1-5.

Knowledge of global network state is crucial for several innovative network optimization techniques. However, these techniques are often evaluated in simulation environments with omniscient knowledge about the network at individual nodes, which is not realistic in practical scenarios. In fact, an individual node's scope of the network is limited in practice since it is able to overhear the wireless channel only locally, and explicit notification about global network state would result in large overhead.

In this thesis project, you are going to engineer features and learning algorithms that allow nodes to gain knowledge about distant parts of a network just by overhearing the wireless channel. The difficulty is to identify features that comprise valuable information from distant nodes, which we believe might be feasible since multi-hop packet transfers may implicitly allow to monitor how distant nodes interact with the network.

 This topic is for you if you are interested in machine learning, wireless networks, and practical experimenting. The project might be co-supervised by another researcher from the collaborative research center MAKI, who is specialized either in the field of topology control, autonomous agents or machine learning techniques.

Bluetooth allows direct device-to-device communication, for instance, between smartphones. Especially BT Low Energy was conceived to be very energy-efficient. This is why vendors allow Bluetooth background operation which is crucial for Disruption-Tolerant Networks (DTNs) as smartphones act as data mules and therefore have to accept new “bundles” as they pass other nodes without user interaction.

In this thesis, you will first explore whether Bluetooth (Low Energy) is a suitable candidate link layer for ad hoc and disruption-tolerant networks. This includes energy efficiency, transmission speed, disruption tolerance, and cross-vendor compatibility.

Finally, you will implement a Bluetooth convergence layer in IBR-DTN [1] to enable DTN communication between (Android) smartphones without infrastructure.

  • BT/BT-LE performance/practicality analysis
    • Energy consumption (scanning, data transmission, …)
    • Transmission speed (1-1, 1-n, …, depending on distance, …)
    • Disruption tolerance (how long does it take for BT to realize that a connection is broken?)
    • Cross-vendor (Android, iOS, …)
  • Implement a BT convergence layer for IBR-DTN [1]
    • Neighbor discovery (energy efficient, …)
    • Data transmission (based on TCPCL?)

     

[1] https://github.com/ibrdtn




Prof. Dr.-Ing. Matthias Hollick

Technische Universität Darmstadt
Department of Computer Science
Secure Mobile Networking Lab 

Mornewegstr. 32 (S4/14)
64293 Darmstadt, Germany

Phone: +49 6151 16-25472
Fax: +49 6151 16-25471
office@seemoo.tu-darmstadt.de

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