Post-Doctoral Researcher on Applications of Control-flow Equivalence to Systems and Security

Teaser Text

Applications are invited for a fully funded three-year postdoctoral position aimed at the intersection of theoretical computer science, computer systems, and security. The topic of the research will be centered on applying techniques from automata theory and programming language semantics within program similarity detection, with applications to recurrent vulnerability detection, as well as optimizing compilers, with a focus on code specialization and abstraction. This is a unique position that involves skills both in theory and software implementation.

In more detail, programming language theory commonly uses automata to describe the behavior of a program from an operational point of view; in systems, control flow graphs can be seen as a different approach to the same principle, used to reason about (among other matters) compiler optimization. In this project, we will investigate theoretical methods to represent control flow graphs as automata and subsequently apply these novel methods in the domains of computer systems as well as security. Within computer systems, we wish to investigate more relaxed implementations of function merging based on bisimulation. In security, we will use these theoretical foundations to develop code equivalence and similarity detection methods, possibly using SMT-based techniques.

Key publications:

• Outrunning Big KATs: Efficient Decision Procedures for Variants of GKAT. Cheng Zhang, Qiancheng Fu, Hang Ji, Ines Santacruz Del Valle, Alexandra Silva, Marco Gaboardi; https://doi.org/10.1007/978-3-032-22723-2_14
• CF-GKAT: Efficient Validation of Control-Flow Transformations. Cheng Zhang, Tobias Kappé, David E. Narváez, Nico Naus; https://doi.org/10.1145/3704857
• Eradicating the Unseen: Detecting, Exploiting, and Remediating a Path Traversal Vulnerability across GitHub. Jafar Akhoundali, Hamidreza Hamidi, Kristian F. D. Rietveld, and Olga Gadyatskaya; https://doi.org/10.1145/3708821.3736220
• Function Merging by Sequence Alignment. Rodrigo C. O. Rocha, Pavlos Petoumenos, Zheng Wang, Murray Cole, and Hugh Leather; https://doi.org/10.1109/CGO.2019.8661174

What you will do

• Develop theory aimed at applying concepts around bisimilarity to control flow graphs, with an eye towards applications in compiler engineering and security;
• Design algorithms to put this theory to work for its intended application, along with the necessary optimizations to achieve a feasible runtime;
• Implement and benchmark those algorithms, to develop push-button solutions that can be applied to real-world source and binary code today;
• Publish your research findings in top-tier conferences, and present your work at conferences, contributing to the scientific community's body of knowledge;
• Get involved with LIACS as a whole, for instance by co-supervising student theses, taking place in committees, or assisting in teaching – the exact responsibilities here depend on your preferences.
  
  

  You will be a member of both the Theory and Systems & Security clusters at LIACS, and supervised by Tobias Kappé (Theory), Kristian Rietveld and Olga Gadyatskaya (both Systems & Security).

Where you will work

The Faculty of Science is a world-class faculty where staff and students work together in a dynamic international environment. It is a faculty where personal and academic development are top priorities. Our people are committed to expand fundamental knowledge by curiosity and to look beyond the borders of their own discipline; their aim is to benefit science, and to contribute to addressing the major societal challenges of the future. The research carried out at the Faculty of Science is very diverse, ranging from mathematics, information science, astronomy, physics, chemistry and bio-pharmaceutical sciences to biology and environmental sciences. The research activities are organised in eight institutes. These institutes offer eight bachelor’s and twelve master’s programmes. The faculty has grown strongly in recent years and now has more than 2.300 staff and almost 5,000 students. We are located at the heart of Leiden’s Bio Science Park, one of Europe’s biggest science parks, where university and business life come together. For more information, see www.universiteitleiden.nl/en/science  and  http://workingat.leiden.edu/
The Leiden Institute of Advanced Computer Science (LIACS) is the Artificial Intelligence and Computer Science Institute in the Faculty of Science of Leiden University. We offer courses at the Bachelor and Master of Science level in Artificial Intelligence, Computer Science, ICT in Business, Media Technology, and Bioinformatics. According to an independent research visitation, we are one of the foremost computer science departments of the Netherlands. We strive for excellence in a caring institute, where excellence, fun, and diversity go hand in hand. We offer a clear and inviting career path to young and talented scientists with the ambition to grow. For more information about LIACS, see http://www.cs.leiden.edu

What you bring

We are looking for candidates who fit the following criteria.

• In possession of a PhD or are in the last stretch of their PhD program;
• Have published work in either theoretical topics (such as automata theory, decision procedures, programming language semantics, verification) or systems and security (e.g., automated vulnerability detection, compilers);
• Curious to develop their theory-oriented expertise with research applied to systems and security, or vice versa, add more theory-oriented skills to a portfolio centered around systems or security research;
• Having experience developing and optimizing non-trivial software projects; experience using LLVM and/or AST libraries is preferred;
• Would enjoy developing and benchmarking proof-of-concept implementations of new algorithms and methodologies developed over the course of the research;
• Eager to aim for publication at top-tier conferences such as CCS, USENIX Security, CAV, and PLDI;
• Available to start quickly; the preferred starting date is September 1, 2026, or as soon as possible thereafter.

What we offer

What we value

Promoting an inclusive community is central to Leiden University’s values and vision. We strive to be an open community in which all students and staff members feel valued and respected, and are able to fully develop themselves. We consider an inclusive academic environment, where students and staff can share their experiences and viewpoints, to be essential for the development of talent.

Want to apply or find out more?