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01. Research project

Cryptographic Formalisation, Evaluation and Design of Perceptual Hash Functions

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    Formalising PHF security: Establishing comprehensive threat models and essential security properties for perceptual hash functions.
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    Systematic cryptanalysis: Conducting in-depth analysis of deployed functions to uncover shared vulnerabilities, standardise adversarial models, and define attack vectors.
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    Mathematical properties: Exploring the theoretical limits of current designs, specifically focusing on linearity and differentiability, to prove the feasibility (or inexistence) of inherently non-linear PHFs.
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    Introducing keyed PHFs: Developing novel keyed designs to create openly verifiable systems that remain resilient against adversarial manipulation, even when the algorithm is public.
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    Formal security modelling: Shifting PHF evaluation from empirical, ad-hoc testing to a rigorous framework supported by formal analysis and security proofs.

02. Publications

Sorted by year
2026

White-Box Attacks on PhotoDNA Perceptual Hash Function

Maxime Deryck, Diane Leblanc-Albarel, Bart Preneel

IACR ePrint Archive

03. Master's thesis

2026

Cryptography meets Finite Geometry

Supervisors: Prof. Jan De Beule (VUB) & Prof. Leo Storme (UGent)

This thesis highlights the interplay between cryptography and finite geometry. The first part provides a literature study on code constructions for code-based cryptography using scattered subspaces, alongside an analysis of the historic cryptanalysis of the GPT cryptosystem. In the second part, novel results are formulated regarding the number of non-bent components of quadratic APN functions that can be used in symmetric block ciphers. These results were obtained using a new connection with projective hypersurfaces and Reed-Muller codes.