Modern digital systems fundamentally rely on the secure transmission and storage of information. Cryptology provides the core techniques for protecting information in the presence of active adversaries. In this thesis, we focus on the provable security of permutation-based cryptography, which has become central to lightweight symmetric schemes, particularly through the sponge construction. The work strengthens their theoretical foundations by tightening some existing security bounds, introducing new constructions that improve on current approaches, and carrying out targeted analyses that lead to both stronger guarantees and greater efficiency.
In 2021, Charlotte Lefevre completed a master of science in applied mathematics at the Université Grenoble Alpes (France). Her master thesis, with subject time-memory tradeoffs for large-weight syndrome decoding in ternary codes, was supervised by Pierre Karpman at the Laboratoire Jean Kuntzmann, Grenoble (France). In 2021, she started a Ph.D. at Radboud University under the supervision of Bart Mennink and Joan Daemen. During her Ph.D., she completed an internship at CSEM (Switzerland) on post-compromise security for IOT settings, under the supervision of Damian Vizár.