TY - CHAP A1 - Saatjohann, Christoph A1 - Ising, Fabian A1 - Schinzel, Sebastian T1 - KIM: Kaos In der Medizin T2 - Sicherheit, Schutz und Zuverlässigkeit: Konferenzband der 12. Jahrestagung des Fachbereichs Sicherheit der Gesellschaft für Informatik e.V. (GI) N2 - Die sichere E-Mail-Infrastruktur für Ärzt*innen, Apotheker*innen, Krankenversicherungen und Kliniken in Deutschland, KIM - Kommunikation im Gesundheitswesen - ist mit über 200 Millionen E-Mails in den vergangenen zwei Jahren eine der am meisten genutzten Anwendungen in der Telematikinfrastruktur. Mit dem Ausgeben von S/MIME-Zertifikaten für alle medizinische Beteiligten in Deutschland verspricht KIM sichere Ende-zu-Ende-Verschlüsselung von E-Mails zwischen Heilberufler*innen in ganz Deutschland. In diesem Paper analysieren wir die KIM-Spezifikation sowie eine beispielhafte KIM-Installation in einer deutschen Zahnarztpraxis. Wir zeigen, dass KIM kryptografisch ein sehr hohes Sicherheitslevel erfüllt, doch in der Verarbeitung der E-Mails bei den Clients eine schwerwiegende Sicherheitslücke besteht. Weiterhin zeigen wir zwei Sicherheitslücken in dem KIM-Verarbeitungsmodul eines großen deutschen Unternehmens für medizinische Software. Diese Defizite zeigen außerdem Mängel in dem verpflichtenden Zulassungsprozess der KIM-Komponenten auf. Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:836-opus-178072 ER - TY - JOUR A1 - Pogorzelski, Jens A1 - Horsthemke, Ludwig A1 - Homrighausen, Jonas A1 - Stiegekötter, Dennis A1 - Gregor, Markus A1 - Glösekötter, Peter T1 - Compact and Fully Integrated LED Quantum Sensor Based on NV Centers in Diamond JF - Compact and Fully Integrated LED Quantum Sensor Based on NV Centers in Diamond N2 - Quantum magnetometry based on optically detected magnetic resonance (ODMR) of nitrogen vacancy centers in diamond nano or microcrystals is a promising technology for sensitive, integrated magnetic-field sensors. Currently, this technology is still cost-intensive and mainly found in research. Here we propose one of the smallest fully integrated quantum sensors to date based on nitrogen vacancy (NV) centers in diamond microcrystals. It is an extremely cost-effective device that integrates a pump light source, photodiode, microwave antenna, filtering and fluorescence detection. Thus, the sensor offers an all-electric interface without the need to adjust or connect optical components. A sensitivity of 28.32nT/Hz−−−√ and a theoretical shot noise limited sensitivity of 2.87 nT/Hz−−−√ is reached. Since only generally available parts were used, the sensor can be easily produced in a small series. The form factor of (6.9 × 3.9 × 15.9) mm3 combined with the integration level is the smallest fully integrated NV-based sensor proposed so far. With a power consumption of around 0.1W, this sensor becomes interesting for a wide range of stationary and handheld systems. This development paves the way for the wide usage of quantum magnetometers in non-laboratory environments and technical applications. KW - Diamond Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:836-opus-175692 VL - 2024 IS - 24(3) ER - TY - CHAP A1 - Völker, Timo A1 - Tüxen, Michael T1 - Packet Too Big Detection and its Integration into QUIC T2 - 2023 16th International Conference on Signal Processing and Communication System (ICSPCS) N2 - A communication over an Internet Protocol (IP) based network fails if an endpoint sends packets that are too big to reach their destination and if the sender is unable to detect that. The node on the path that drops these packets should respond with a Packet Too Big (PTB) message. However, multiple scenarios exist in which the sender will not receive a PTB message. Even if it does, it refrains from using the information in case it suspects that a potential attacker forged the message. In particular, we are not aware of any implementation of the secure transport protocol QUIC (e.g., used by HTTP/3) that processes PTB messages. In this paper, we present a novel parameterizable PTB detection algorithm for reliable transport protocols that does not depend on PTB messages. We further describe how to integrate our algorithm into QUIC, present results from an evaluation using the algorithm within a QUIC simulation model and, based on these results, suggest concrete parameter values. KW - PMTUD KW - PTB KW - black hole KW - transport protocol KW - QUIC Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:836-opus-174119 SN - 979-8-3503-3351-0 PB - IEEE CY - New York, NY, USA ER - TY - GEN A1 - Fairhurst, Gorry A1 - Jones, Tom A1 - Tüxen, Michael A1 - Rüngeler, Irene A1 - Völker, Timo T1 - Packetization Layer Path MTU Discovery for Datagram Transports Y1 - 2020 UR - https://www.rfc-editor.org/info/rfc8899 U6 - http://dx.doi.org/10.17487/RFC8899 PB - IETF ER - TY - CHAP A1 - Salewski, Falk A1 - Bodenburg, Sven A1 - Malechka, Tatsiana ED - Jäkel, Jens ED - Reiff-Stephan, Jörg ED - Schwarz, Jens André T1 - Durchgängige Digitalisierung industrieller Abläufe am Beispiel der Modellfabrik der FH Münster T2 - Tagungsband AALE 2023 - Mit Automatisierung gegen den Klimawandel N2 - Die Modellfabrik der FH Münster erlaubt durch den Umfang und die Komplexität der enthaltenen Automatisierungsaufgaben sowie einen Aufbau aus industriellen Komponenten eine praxisnahe Lehre im Bereich aktueller Anlagenautomatisierung und darüber hinausgehenden Funktionen im Sinne einer durchgängigen Digitalisierung. Die verwendete Unterscheidung der durchgängigen Digitalisierung in horizontale und vertikale Verknüpfungen wird veranschaulicht. Aufbauend auf Erfahrungen mit der Vorgängeranlage werden Neuerungen der 2021 aufgebauten neuen Modellfabrik vorgestellt. Neuerungen umfassen insbesondere die Modularisierung der Anlage, das umgesetzte Sicherheitskonzept, einen Webshop mit Onlinekonfigurator, eine Webvisualiserung des Anlagenzustandes inklusive der Energieverbräuche, sowie Möglichkeiten zur virtuellen Inbetriebnahme. Weiterhin wird das aktuelle Konzept zur Erweiterung der horizontalen digitalen Durchgängigkeit mittels der Einbindung eines autonomen mobilen Roboters in die Modellfabrik vorgestellt. KW - Modellfabrik, Industrie 4.0, Cyber-Physical Systems, Durchgängige Digitalisierung, Autonomer mobiler Roboter, Lehre Y1 - 2023 UR - https://nbn-resolving.org/urn:nbn:de:bsz:l189-qucosa2-839648 SN - 978-3-910103-01-6 U6 - http://dx.doi.org/10.33968/2023.44 ER - TY - JOUR A1 - Löchte, Andre A1 - Rojas Ruiz, Ignacio A1 - Glösekötter, Peter T1 - Battery State Estimation with ANN and SVR Evaluating Electrochemical Impedance Spectra Generalizing DC Currents JF - Applied Sciences N2 - The demand for energy storage is increasing massively due to the electrification of transport and the expansion of renewable energies. Current battery technologies cannot satisfy this growing demand as they are difficult to recycle, as the necessary raw materials are mined under precarious conditions, and as the energy density is insufficient. Metal–air batteries offer a high energy density as there is only one active mass inside the cell and the cathodic reaction uses the ambient air. Various metals can be used, but zinc is very promising due to its disposability and non-toxic behavior, and as operation as a secondary cell is possible. Typical characteristics of zinc–air batteries are flat charge and discharge curves. On the one hand, this is an advantage for the subsequent power electronics, which can be optimized for smaller and constant voltage ranges. On the other hand, the state determination of the system becomes more complex, as the voltage level is not sufficient to determine the state of the battery. In this context, electrochemical impedance spectroscopy is a promising candidate as the resulting impedance spectra depend on the state of charge, working point, state of aging, and temperature. Previous approaches require a fixed operating state of the cell while impedance measurements are being performed. In this publication, electrochemical impedance spectroscopy is therefore combined with various machine learning techniques to also determine successfully the state of charge during charging of the cell at non-fixed charging currents. Keywords: electrochemical impedance spectroscopy; artificial neural networks; support vector regression; zinc-air battery; state estimation; state of charge KW - Battery State Estimation Y1 - 2021 SN - 978-84-1117-173-1 U6 - http://dx.doi.org/10.3390/app12010274 VL - 12 IS - 1 SP - 275 ER - TY - JOUR A1 - Homrighausen, Jonas A1 - Horsthemke, Ludwig A1 - Pogorzelski, Jens A1 - Trinschek, Sarah A1 - Glösekötter, Peter A1 - Gregor, Markus T1 - Edge-Machine-Learning-Assisted Robust Magnetometer Based on Randomly Oriented NV-Ensembles in Diamond JF - Sensors N2 - Quantum magnetometry based on optically detected magnetic resonance (ODMR) of nitrogen vacancy centers in nano- or micro-diamonds is a promising technology for precise magnetic-field sensors. Here, we propose a new, low-cost and stand-alone sensor setup that employs machine learning on an embedded device, so-called edge machine learning. We train an artificial neural network with data acquired from a continuous-wave ODMR setup and subsequently use this pre-trained network on the sensor device to deduce the magnitude of the magnetic field from recorded ODMR spectra. In our proposed sensor setup, a low-cost and low-power ESP32 microcontroller development board is employed to control data recording and perform inference of the network. In a proof-of-concept study, we show that the setup is capable of measuring magnetic fields with high precision and has the potential to enable robust and accessible sensor applications with a wide measuring range. Y1 - 2023 UR - https://www.mdpi.com/1424-8220/23/3/1119 U6 - http://dx.doi.org/10.3390/s23031119 VL - 23 IS - 3 ER - TY - CHAP A1 - Ising, Fabian A1 - Poddebniak, Damian A1 - Kappert, Tobias A1 - Saatjohann, Christoph A1 - Schinzel, Sebastian T1 - Content-Type: multipart/oracle -- Tapping into Format Oracles in Email End-to-End Encryption T2 - 32nd USENIX Security Symposium N2 - S/MIME and OpenPGP use cryptographic constructions repeatedly shown to be vulnerable to format oracle attacks in protocols like TLS, SSH, or IKE. However, format oracle attacks in the End-to-End Encryption (E2EE) email setting are considered impractical as victims would need to open many attacker-modified emails and communicate the decryption result to the attacker. But is this really the case? In this paper, we survey how an attacker may remotely learn the decryption state in email E2EE. We analyze the interplay of MIME and IMAP and describe side-channels emerging from network patterns that leak the decryption status in Mail User Agents (MUAs). Concretely, we introduce specific MIME trees that produce decryption-dependent net work patterns when opened in a victim’s email client. We survey 19 OpenPGP- and S/MIME-enabled email clients and four cryptographic libraries and uncover a side-channel leaking the decryption status of S/MIME messages in one client. Further, we discuss why the exploitation in the other clients is impractical and show that it is due to missing feature support and implementation quirks. These unintended defenses create an unfortunate conflict between usability and security. We present more rigid countermeasures for MUA developers and the standards to prevent exploitation. Y1 - 2023 UR - https://www.usenix.org/conference/usenixsecurity23 PB - USENIX Association ER - TY - CHAP A1 - Mayer, Peter A1 - Poddebniak, Damian A1 - Fischer, Konstantin A1 - Brinkmann, Marcus A1 - Somorovsky, Juraj A1 - Schinzel, Sebastian A1 - Volkamer, Melanie T1 - "I don’t know why I check this...'' - Investigating Expert Users' Strategies to Detect Email Signature Spoofing Attacks T2 - Eighteenth Symposium on Usable Privacy and Security (SOUPS 2022) N2 - OpenPGP is one of the two major standards for end-to-end email security. Several studies showed that serious usability issues exist with tools implementing this standard. However, a widespread assumption is that expert users can handle these tools and detect signature spoofing attacks. We present a user study investigating expert users' strategies to detect signature spoofing attacks in Thunderbird. We observed 25 expert users while they classified eight emails as either having a legitimate signature or not. Studying expert users explicitly gives us an upper bound of attack detection rates of all users dealing with PGP signatures. 52% of participants fell for at least one out of four signature spoofing attacks. Overall, participants did not have an established strategy for evaluating email signature legitimacy. We observed our participants apply 23 different types of checks when inspecting signed emails, but only 8 of these checks tended to be useful in identifying the spoofed or invalid signatures. In performing their checks, participants were frequently startled, confused, or annoyed with the user interface, which they found supported them little. All these results paint a clear picture: Even expert users struggle to verify email signatures, usability issues in email security are not limited to novice users, and developers may need proper guidance on implementing email signature GUIs correctly. Y1 - 2022 UR - https://www.usenix.org/conference/soups2022/presentation/mayer SN - 978-1-939133-30-4 SP - 77 EP - 96 PB - USENIX Association CY - Boston, MA ER - TY - CHAP A1 - Löchte, Andre A1 - Thranow, Jan-Ole A1 - Winters, Felix A1 - Glösekötter, Peter T1 - Analysis of switching electronics for metal-air batterie T2 - ICECET, Prag N2 - The subject of this paper is the analysis of various switching electronics for batteries with separate electrodes for charging and discharging. The aim is to find a switching method that is energy-efficient on the one hand, but also economically viable on the other. Both relays and MOSFETs are suitable for switching between the electrodes. Both variants have advantages and disadvantages. The results show that a solution with MOSFETs is generally more energy-efficient, but requires a large number of cycles to be economically viable compared to the relay. KW - Analysis Y1 - 2022 U6 - http://dx.doi.org/10.1109/ICECET55527.2022.9872910 ER -