I spent my academic life at the Technische Universität Darmstadt and the University of Birmingham and I have also been at several other universities as a guest lecturer. My main research interests are applied cryptography as well as information security. I have published several papers about attacks on wireless protocols, side channel attacks on cryptographic protocols and attacks against ciphers and other cryptographic schemes. The main focus of my current research are the Internet of Things, the security of critical infrastructures as well as wireless protocols.
2015-today: Lecturer at the University of Birmingham, UK
Since October 2015, I’m a Lecturer at the University of Birmingham, England, UK. I’m teaching Secure Programming as well as Incidents Management and Forensics. I am continuing my research I began in Darmstadt as well as I am also starting in new fields of research. This includes the Internet of Things as well as the security of other wireless technologies.
2012 – 2015: Post-Doc at Technische Universität Darmstadt, Germany
After having finished my PhD, I joined the Security Engineering group of Prof. Katzenbeisser at Technische Universität Darmstadt as a Post-Doc researcher. I worked on several topics within his group.
Embedded systems security
After I finished my PhD, I analysed an electronic locking system of one of the major companies in this market in Europe and found practical attacks on that system, that allows unauthorized users to open doors within seconds to minutes without leaving any traces. Of course the manufacturer was notified about this issue prior to the publication of the results and we jointly discussed countermeasures against the attacks. The results have been published at ACM CCS 2013.
Designing secure systems
I was working on a joint project with Deutsche Bahn and DIN (the German equivalent of BSI) on a standard for IT-Security in railway applications. While traditional hardware for securing railway traffic is often purely mechanical or uses analogue telephone lines, modern systems for managing railway grids are based on off-the-shelf networking components and standard operating systems. Future generations of railway grids will be managed remotely from a very few central control rooms in a country. Since equipment from many different suppliers is used to build and maintain such a railway grid, a common standard is needed to ensure a basic level of security for all components. Our proposal for such a standard that is based on IEC62443 will be published by DIN under the name DIN VDE V 0831-104 and an English translation is also planned so that the standard can also be used internationally.
Developing attack methods and defences
Jointly with researchers from Bochum and Erlangen, I analysed the security of implementations of the SSL/TLS protocol. We were able find flaws in OpenSSL and Java JSSE that can be exploited remotely. However the attack on Java was much more effective as a similar attack on OpenSSL. We could show that throwing an exception for an incorrect padding is much more time consuming that just returning an error value in C. As a result, the timing difference between a correctly and an incorrectly padded message is clearly visible. Since most APIs for cryptography in high level languages throw exceptions for problems such as an incorrect padding scheme, we could suggest better and more secure ways of designing and using cryptography libraries. The results have been published at USENIX Security 2014.
Privacy preserving technologies
To improve the privacy in consumer devices, I analysed current Smart-TVs using HbbTV, a standard for bringing DVB and Internet content together on a modern TV. We were able to show that current Smart-TVs leak the consumers watching preferences to the TV stations, but countermeasures are possible.
I also helped in the development of new privacy friendly communication network. To allow anonymous microblogging in environments where Internet access is not always available or might be unavailable for a long time, we developed MoP-2-MoP, a distributed secure and anonymous microblogging system that can be run on smartphones and communicates via Bluetooth on a P2P basis.
I have helped with the development of new cryptographic methods for performing secure multi-party computations. One of the results was an ORAM scheme that is sufficiently efficient to store and perform calculations on a full human genome sequence. I also spend more time in biology and genetic analysis by implementing algorithms to detect image manipulation in academic publications that contain western blot test results or similar tests. Such tests are used to detect the presence of DNA, RNA or proteins.
2007-2011: PhD student at Technische Universität Darmstadt, Germany
I decided to start a PhD in the cryptography research group of Prof. Buchmann. I decided to focus on DECT based cordless phones as the main topic of my thesis, since it has a major real world impact and it requires skills from cryptography and IT-security. At the beginning of my PhD thesis, almost nothing was known about DECT security. The phones use custom encryption and authentication algorithms that were only available under an NDA. During my PhD thesis, these algorithms were reverse engineered and I designed attacks on both algorithms. The results have been published at FSE2010 and WISEC2011 and other important conferences. I finished my PhD on September 11th 2011.
Besides my PhD, I supported many lectures and worked on third party funded research projects. I also analysed other encryption algorithms and published attacks on wireless LANs as well as on the DVB-CSA algorithm that is used to protect Pay-TV. The attack allows near real-time encryption of some TV transmissions that are protected by DVB-CSA.
Side channel attacks
I worked on side channel attacks against implementations of the McEliece PKC and countermeasures. The attacks can be used to decrypt a ciphertext when an decryption algorithm can be observed and timing and/or power traces can be collected.
2003-2007: Computer Science Diploma and Bachelor student at Technische Universität Darmstadt
Since I have developed a strong interest in IT Security and computer science in general, I decided to go to Darmstadt to study computer science. In 2006, I finished my Bacholor degree. The topic of my bachelor thesis was the development of a TLS stack for the Java 2 Micro Edition for mobile devices, which is still used today within the Boucycastle cryptographic library in Java. In 2007 I finished my diploma. Because I had a strong interest in cryptography and the real world impact of computer science, I selected math and law as the two minors in my diploma. The topic of my diploma thesis were attacks on WEP secured WiFi networks.
For a full list of my publications, see the publications page.