Oberseminar Rechnernetze und Telematik (Sommer 2025)

In the oberseminar, talks are held on selected topics, as well as final presentations of master's & bachelor's theses, and projects. The seminar takes place hybridly:

• In room 051-02-008, as well as via
• Zoom - link¹ (Meeting-ID: 879 6692 5056, password: WR6RriwYD)

Next Oberseminar Talks:

• 18.06.2025 14:00–14:30 Matthias Bundy, Bachelor Thesis Final Presentation
  Title:
  A general model of the mutual impedance between Hertzian Dipoles
  Abstract: We derived a new formula describing the mutual impedance between Hertzian dipoles. The Hertzian dipole model is an antenna model describing the behaviour of very small and infinitessimally thin antennas. The mutual impedance models the mutual coupling between each a pair of dipoles. In the case of parallel oriented planar placed dipoles a formula describing the mutual impedance has already been derived in 2009. We extended this formula in this Thesis to arbitrary oriented and positioned Hertzian dipoles. This has applications to classical information theory, especially in the MIMO area.
• 18.06.2025 14:35–15:05 Jan Christian Cichosz, Bachelor Project Status Report
  

  Title:
  a library for visualising mental card game in rust: mcg_visual
  Abstract: In the presentation he would like to show the higher-level architecture the library can run on and how he grouped his code together. The libraries his code is using will also be briefly showcased. Afterwards he plans to show which traits and structs his library provides and how they can be used.

• 18.06.2025 15:15–15:30 Till Hoffmann,  Bachelor Thesis Kickoff Presentation
  

  Title: Designing an Embedded Domain-Specific Language for Secure Board Games

  Abstract: This thesis focuses on the architectural design of an embedded Domain-Specific Language (eDSL) specifically engineered for creating secure board games in a peer-to-peer (P2P) environment. My eDSL aims to significantly expand the scope of securely playable games by providing language constructs that inherently support the rules and interactions of a wide array of board games. This work seeks to deliver a conceptual framework that outlines how to simplify the development of complex, verifiable, and fair multiplayer board games, enabling secure play without the need for a trusted central authority.

• 18.06.2025 15:30–15:45 Arthur Diener,  Project  Kickoff Presentation
  
  Title: Self-Stabilizing SkipNet using Random Flip Operations
  Abstract:  the idea, the  approach, and proposed plan for the simulation 

Previous Oberseminar Talks:

• 04.06.2025 13:00–14:00 Veena Iyer, Master Thesis Final Presentation
  
  Title:
  Evaluation of a New Mobile Communication Standard for Realizing Energy Efficient Sensor Meshes
  
  Abstract:
  The thesis focuses on a new mobile radio standard called Digital Enhanced Cordless Telecommunications New Radio Plus (DECT NR+), which promises the development of self-management and self-healing mesh networks that can be provisioned and operated in an energy efficient manner. The aim of this thesis is to evaluate DECT NR+ in terms of its applicability for energy-limited sensor systems. The performance metrics under investigation include latency, throughput, communication range, and energy consumption. Field tests are conducted using nRF9161 boards, which support communication over the DECT NR+ band, and the results are compared with those of established WirelessHART technology to assess whether DECT NR+ offers a superior alternative. The findings demonstrate that DECT NR+ outperforms WirelessHART in three key parameters – range of communication, latency, and throughput – with potential for optimization in energy consumption, indicating its promise as a replacement technology.
  
  Additionally, this thesis presents a distributed algorithm named Energy-aware Node Optimization and Routing Algorithm (ENORA), developed in Python, that enables dynamic switching between forwarding and routing roles based on the energy levels of individual nodes. This supports a self-organizing, self-healing, and energy-efficient network. Initially, a basic version of the algorithm is developed under sub-optimal conditions, where each node attempts to communicate with all others, resulting in high energy consumption and packet error rates. To address this, the algorithm is optimized by introducing connectivity constraints based on geometric distance and by implementing energy thresholds for role switching. Further enhancements include periodically activating the radio of the forwarding nodes to detect nearby transmissions. If a node identifies undelivered messages, it transitions to a READY-TO-ROUTE state, signaling its availability to route data and potentially assume the router role based on network conditions. These optimizations significantly reduce energy consumption and lower the packet error rate, although the latter remains relatively high. The balance of energy efficiency and reliability emerges as a key trade-off, which is identified as a direction for future work. This simulation demonstrates a partial mesh network reflecting the tree-of-trees topology of DECT NR+, corresponding to the roles of sink, relay, and leaf. It also showcases the self-organizing and self-healing capabilities of the DECT NR+ standard, opening up significant potential for future investigations and advancements in this field.
• 04.06.2025 14:00–14:15 Jan Orlanski, Bachelor Thesis Kickoff Presentation
  
  Title:
  Automated Extraction of Zero-Knowledge Proofs for Rule Control in Mental Card Games from a CGDL
  
  Abstract:
  Mental card games are played over a distance and without a trusted third party. To ensure that all players follow the rules under these circumstances, zero-knowledge proofs are required. These proofs allow players to show that they follow the rules without revealing their cards. The goal of this thesis is to provide zero-knowledge proofs for rule control that cover as wide a range of games as possible. In order to ensure fair play even for new or unknown games, game descriptions in Card Game Description Language form are used to determine which of the proofs are necessary for the respective game.
• 04.06.2025 14:20–14:40 Benjamin Schliebitz, Bachelor Project Kickoff Presentation
  
  Title:
  P2P Communication for Mental Card Game Nodes
  
  Abstract:
  The project aims to implement peer-to-peer communication between mental card game (MCG) nodes. The iroh library will be used to achieve NAT hole punching and public key-based addressing, along with a custom address tracker for establishing sessions. Neither the fallback relay server nor the address tracker will be treated as trusted parties. The implementation will support the transmission of data types required by the shuffling algorithm, with extensibility for other types and operations. The code will be integrated into the existing frontend codebase and will include a GUI for pairing nodes and sending example data between player nodes.
• 04.06.2025 14:45–15:15 Marvin Stoetzel, Bachelor Project Kickoff Presentation
  
  Title:
  A Web-Based Client for Decentralized, Privacy-Preserving Mental Poker
  
  Abstract:
  This Bachelor’s Project aims to implement a web-based client for playing decentralized, privacy-preserving mental poker using zero-knowledge proofs. The goal is to build a functional and user-friendly frontend that enables multiple players to engage in a game of Texas Hold’em while preserving the secrecy of private information and ensuring fairness without a trusted third party.
  
  The project includes:
  1. Developing a GUI frontend using Rust and WebAssembly for in-browser gameplay.
  2. Implementing a distributed state machine to manage multi-party game logic.
  3. Integrating cryptographic mechanisms for secure card shuffling, dealing, and selective revelation using ElGamal encryption.
  4. Exploring methods for synchronizing distributed game state (e.g., peer-to-peer messaging or blockchain).
  5. Implementing logic for betting rounds, timeouts, disconnections, and winner determination.
  
  The resulting system will serve as the interactive frontend and protocol interface for the zero-knowledge poker protocol, which will be further developed in the accompanying Bachelor’s Thesis.
• 04.06.2025 15:30–15:45 Arthur Diener, Bachelor Project Kickoff Presentation
  
  Title:
  Self-Stabilizing SkipNet using Random Flip Operations
  
  Abstract:
  This project presentation introduces the idea, approach, and plan for simulating a self-stabilizing SkipNet using random flip operations.
• 28.05.2025 14:00-14:30 Marcel Schuhmacher, Bachelor Thesis kickoff presentation
  
  

  Title: Solving the 2D ILDARS problem for one source and two walls.

  Abstract: The ILDARS problem is defined as a setup involving a single receiver, a known number of walls and sources, and a set of signals originating from the sources and arriving at the receiver from known directions, with known time differences between each signal.
  These signals can be line-of-sight signals or be reflected (multiple times) off the (planar) walls.
  The main objective is to recover the location of the source, or in addition, the full geometry of the setup.
  Our goal is to solve the 2D ILDARS problem for one source and two walls. More specifically, we aim to determine for which numbers and constellations of signals the problem is solvable, and for which it is not.

• 28.05.2025 14:45-15:15 Robert Meysen, Bachelor Project kickoff presentation
  

  
  Title : Modelling the Carbon emission of construction machinery based on their activity using sensor data
  
  Abstract : In this bachelor’s project I aim to create a model (or several models) on how to estimate a construction machine’s carbon footprint during road construction. To come up with a model, the energy consumption for different activity levels of a machine will be assessed, especially with regards to the measurements of the sensors. Where possible, the measured machine activity will then be put into relation with the required use of said machine in the construction of a road with regards to the construction sites size and other conditions of the site.
  Existing research has mostly focused on Life Cycle Assessments (LCAs) where the greenhouse gas emissions of a machine’s “life” are divided into three prats: the construction of a machine, its use phase and its end of life deconstruction (Europe Rental Association, Climate Neutral Group 2019). In the use phase, the carbon footprint is usually made up of the hours of use multiplied by the machine’s fuel consumption (Ibid.). (The transport to construction sites also makes up a part of the carbon footprint of a machine but will not be taken into account for this project.) To come up with concrete numbers, measurements of a machine’s energy usage are necessary.
  With regards to specific machines, the energy usage is sometimes given by the manufacturer with differing consumption levels at light, medium and heavy use (DYNAPAC). The energy usage per hour of different levels of activity will need to be assessed to come up with a quantifiable model. Another aim of this project is then to relate the levels to activity to an area that the machine has been used on. In this way, the machine’s activity and its corresponding emissions can be put in relation to its required use on a road construction site with certain measurements (e.g. length and width of road to be built).
  To achieve the aims of this bachelor’s project, a thorough literature research will be undertaken in order to further assess the potential additional data points that need to be considered for the model. Possibly the project will also include suggestions on measurements about fuel consumption or energy usage of machines if no corresponding data can be found.

  
  
• 28.05.2025 15:20-15:35 Tom Pfirsig, Bachelor Project kickoff presentation
  
  Title: Putting Ring-Signatures to praxis: Create a Webapp to anonymously

  (Ring-)Sign Messages
  
  Abstract: In this kickoff Presentation of my bachelor's project, I will outline the core idea behind the project and the goals I aim to achieve. Additionally, I will present the progress made so far, including the components that have already been implemented.

• 28.05.2025 15:45-16:00 Yi-Chieh Lin Master Project final presentation

  Title : Simulation Comparison of Asynchronous Local Deal-agreement Algorithms in General Graph
  
  Abstract : The research uses the local deal-agreement based algorithm that was proposed by Y. Dinitz et al. in an asynchronous situation to simulate the practical results in various graphs. Asynchronous states that the network is event-based, the transmission of messages is driven by each single event. In the real-world, the simulation of an Asynchronous network can be helpful as it provides the convenience of not waiting for the former one to end, and keep on doing other operations. In this study, we will simulate the self-stabilizing load balancing algorithm in six different graphs: complete graph, ring graph, star graph, WS small world graph, ER random graph and BA scale free graph, and compare the output performance of its modeling scenarios with the fitting curve.

• 21.05.2025 14:00-14:30 Peter Gillesen, Bachelor Thesis final presentation

  Title: HTTP/3 Reverse Proxies: Detecting RFC Violations by Fuzzing

  Abstract: HTTP/3 is on track to become the primary standard for web application communication. While it's increasingly being integrated into modern browsers, there's still much to learn about its security implications. One major concern is reverse proxies, which have shown to play a central role in the emergence of security vulnerabilities related to HTTP. Early work by Pisu et al. (University of Cagliari) focuses on detecting RFC 9114 violations to uncover vulnerabilities such as request smuggling. This bachelor's thesis extends Pisu et al.’s testing framework by adding grammar- and mutation-based fuzzing of HTTP/3 requests to detect deviations from RFC 9114. We evaluated Caddy, Traefik, Haproxy, and Nginx (across HTTP/1.1, HTTP/2, HTTP/3 backends) and found that every proxy tested exhibits at least one RFC 9114 violation. The presented fuzzer uncovered additional issues in five of eight proxy versions compared to the original method. However, the presented approach also offers opportunities for further refinement, including implementing frame-level fuzzing and optimizing mutation strategies.

• 21.05.2025 14:45-15:15 Lukas Frantz, Bachelor Thesis kickoff Presentation

  Title: Designing a (Proof of a) Shuffle Algorithm for Mental Card Games based on Lattice Codes
  Abstract:

  This presentation outlines a plan to design a shuffle algorithm, and a corresponding proof of correctness, for mental card games using lattice-based cryptography. The core idea is to build on the multiparty threshold fully homomorphic encryption scheme from "Multiparty Homomorphic Encryption from Ring-Learning-with-Errors", which enables collaborative encrypted computation. To verify the correctness of the shuffle without revealing the permutation, I aim to adapt techniques from "Lattice-Based Proof of Shuffle and Applications to Electronic Voting", which provides zero-knowledge proofs for shuffles of encrypted commitments. The goal is to construct a practical, verifiable shuffle protocol that is secure against adversaries and can be used in the setting of mental card games.

• 21.05.2025 15:30-16:00 Benedikt Nothhelfer, Bachelor project kickoff presentation

  Title: Scalable Shuffle for Mental Card Games

  Abstract: In this paper we examine the Scalability and Security of Mental Card Games involving many players and cards. Our focus lies on developing an efficient, distributed shuffle algorithm, by using agreements for decision-making, Commitments and Bulletproofs for Zero-Knowledge-Proofs. Our goal is to build a secure, fair and trustworthy protocol that remains practical at a large scale.

• 07.05.2025 14:15-15:45 Christian Schindelhauer, Talk

  Title: Topics for Projects and Theses at the Chair

  Abstract: What are bachelor/master projects/theses? What kind of topics are available at the chair. I will present topics from the area of Localization, Computational Complexity, Peer-to-Peer-Networks, Telocate, MIMO and Near-Field, Visual Cryptography and Mental Card Games 

• 23.04.2025 14:00-14:30 Marcel Schuhmacher,, T Bachelor Project Final Presentation

  Title: Analyzing the oracle ILDARS problem - A casestudy

  Abstract: This project analyzes a previously unsolved instance of the oracle ILDARS problem involving four signals with labels ( ), (w_1), (w_2), (w_1, w_2) and two reflecting walls (w_1, w_2). We focus on determining the distance p between receiver and source, as it remains the only relevant unknown given the line-of-sight signal. By transforming the scenario using mirroring techniques, we derive two independent expressions for a related distance d_1, each depending only on known data and p. Equating these leads to an eighth-degree polynomial in p, which in all computed cases, yields a single verifiable, positive, real solution. This demonstrates that the chosen scenario is solvable.

• 23.04.2025 15:00-15:30 Mika Wilpert, Bachelor Thesis Final Presentation

  Title: Optimization of Bluetooth Low Energy Distance Measurements with Machine Learning

  Abstract: More and more devices require accurate wireless distance measurements with more potential applications to come. While Ultra Wide Band (UWB), the current state-of-the-art method, reaches centimeter level accuracies, its implementation remains expensive, leading to slow adaptation across devices. Bluetooth Low Energy (BLE) based distance measurements repre sent a promising solution to this as the technology is already present on most wireless devices. However, due to noisy measurements, BLE still struggles with accuracies, often only reaching meter level precision. The aim of this work is to test whether applying Machine Learning (ML) to BLE distance measurements could reduce this noise and hence increase accuracy. To test this hypothesis, a dataset of BLE-based distance measurements was collected and used to train and optimize various neural networks (NN) based on different distance measurements techniques such as Received signal strength indicator (RSSI) and phase slope (PS) as well as the combination thereof. The results were then compared to existing PS distance calculations without ML to assess whether ML could increase accuracy. Last, the best performing model’s capacity to extrapolate to new environments was tested with datasets of measurements performed in new environments and different distances than the ones in the training dataset. It was found that the use of ML significantly increased accuracy and models generalized well to new distances and environments. The best model achieved a mean absolute error of 0.051 m in the training environment and 0.243 m in new environments. The different NNs trained also offer choices in terms of complexity versus accuracy. This opens the path to bringing UWB level accuracies to BLE distance measurements, thus broadening the application range of wireless distance measurements.

• 16.04.2025 14:00-14:30 David Stark, Bachelor Thesis Kickoff Presentation
  
  Title: Analysis and Optimization of DTLS for Constrained Networks

  Abstract: Energy efficiency, security and data integrity are more important today than ever before. IoT devices and constrained networks such as Low Power Wide Area Networks (LPWANs) are also playing an increasingly important role in today's world. Of course, the usual factors such as security, reliability and scalability also play a crucial role in these networks. Due to limited resources such as energy and bandwidth, these networks need to use additional protocols and techniques to be competitive. The aim of the work is to transmit data securely in a constrained network (LoRaWAN) using DTLS and a suitable IP stack. Important components such as header compression and fragmentation (SCHC) as well as handshake optimization techniques are used for further optimization. The implementation is tested and evaluated with several devices, whereby key performance metrics such as energy consumption or transmission rate are monitored and optimized. 

• 02.04.2025 14:00-14:30 Viktor Göbel., Master Thesis Kickoff Presentation
  
  Title: Implementierung eines Trusted Platform Module 2.0 zur Absicherung der Boot- und Updateprozesse eines Mikrocontrollers