Thesis Topics

Next Generation Cryptosystems: Post-Quantum Cryptography

In the mid 1990's, Peter Shor found his famous algorithm to factorize large numbers. It soon turned out that this algorithm can be used to break essentially all public-key cryptosystems in practical use today. On the positive side, the type of quantum computer required to run Shor's algorithm isn't available yet -- but there is an urgent need for new "post-quantum" asymmetric cryptosystems, which will survive the advent of reliable large-scale quantum computers.

There is an ongoing effort to study and eventually standardise such cryptosystems, specifically for new "key encapsulation mechanisms" and new "digital signature schemes":

Topics for Bachelor Students

  • The McElice KEM
  • The NTRU and NTRU-Prime KEMs
  • SPHINCS+: A stateless hash-based signature scheme

Topics for Master Students

  • Lattice-Based Cryptosystems
  • Code-Based Cryptosystems
  • Hash-based Digital Signatures

Cryptocurrencies: Payments, Proofs and Power Consumption

In recent years, the idea of hash-based cryptocurrencies, such as Bitcoin, has taken off. A disadvantage of Bitcoin is the dependency on cryptographic "proofs of work", which are, de facto, a "proof of power consumption" and CO2-emission. Thus, we study environmently more friendly alternatives, such as "proofs of stake" and "proofs of storage".

Topics for Bachelor Students

  • Bitcoin and Ripple: A Comparison

Topics for Master Students

  • Proofs of Storage


The specific scope for the topics below can be adjusted for either Bachelor or Master Students.

  • Implementing and Proving Algorithms in SPARK

SPARK is an Ada-based programming language, which is used for the developement of dedicated secure software. SPARK supports the specification and the verification of the information flow of an implementation, as well as pre- and postconditions.  The goal is to implement easy algorithms in SPARK (sorting and searching, the arithmetic of big numbers, etc.), and to prove the implementations using the SPARK toolset.

  • A Simulator/Demonstrator for Grover and Other Quantum Algorithms

Quantum algorithms have the reputation of being difficult to grasp. To some degree, this reputation may be well-deserved -- but not all quantum algorithms are so difficult. The main goal for the thesis is a simplified quantum simulator with a visual interface to implement some simple quantum algorithms, such as Grover's quantum search algorithm. The simulator shall be used to give junior students a first impression of quantum algorithms, e.g., in the context of "Byte the Bytes".

Cryptosystem Design and Cryptanalysis

The specific scope for the topics below can be adjusted for either Bachelor or Master Students.

  • Easy Attacks - Attacking the AEZ Cryptosystem

AEZ (pronounced "easy") is a cryptosystem, which uses four rounds of the AES as the internal building block. The goal is to describe attacks, when this building block is reduced to less than four rounds.

  • Leakage-Resilient Symmetric Cryptosystems

In cryptography, "leakage resilience" is the ability of a cryptosystem to provide security even when the adversary has access to a side-channel, such as, e.g., a power consumption trail from operations using the secret key. The goal is to study symmetric cryptosystems, which have been claimed to be "leakage-resilient" by their designers.

  • Genetic/ Memetic Algorithms for Cryptanalysis

Cryptanalysis, especially nonlinear cryptanalysis, often faces the difficulty of a search space that is far too large to completely analyze. Besides the traditionally used tools, such as SAT-Solvers or MILP-based approaches, the usage of genetic or memetic algorithms seems promising. The goal of this thesis would be to implement a tool for cryptanalysis, which uses such algorithms to find good input differences or nonlinear approximations, and to compare the results with existing techniques.


Thesis Topics for Bachelor Students

  • Privacy-Preserving Record Linkage

Record linkage is a crucial step in many database applications. At the same time, record linkage can be a privacy issue. To what degree is it possible to support record linkage while maintaining a well-specified and quantifiable amount of privacy for the user?

  • Differential Privacy in Smart Traffic Control

Smart cities are not just known for their comfort but also for their habit to collect large amounts of data. One typical example of such a comfortable but data-intensive use case is smart traffic control. If implemented correctly, it can add a lot of features addressing not just comfort but also security. On the other hand, there are many concerns regarding the constant surveillance. What can we do to keep the benefits without giving away privacy? The aim of this work is to find differential privacy mechanisms and strategies for smart traffic control to tackle this issue.

Thesis Topics for Master Students

  • TrueNews II

How to verify a photograph taken while maintaining anonymity? This is a follow-up work of an already existing master thesis where photographs taken were verified in a decentralized way by nearby smartphones. A new signature protocol was created. However, there are ongoing challenges. How to compute credibility? How to transmit credibility? What if some phones are compromised? And how to remain anonymous? The goal of this thesis is to revisit the underlying protocol and to analyze and improve it from a security perspective.