PhD Position F/M Attack Modelling of Symmetric Primitives

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Type de contrat : CDD

Niveau de diplôme exigé : Bac + 5 ou équivalent

Fonction : Doctorant

Contexte et atouts du poste

The main objective of the PhD project is to propose new attack modellings of symmetric primitives.
It will be carried out in the CARAMBA team at Loria, in Nancy, within the framework of the project CRYPTANALYSE of the PEPR CYBERSÉCURITÉ.

Business travels, in France or abroad, could be considered to disseminate the scientific results, in particular at conferences. Travel expenses are covered within the limits of the scale in force.

Mission confiée

Context

When designing a symmetric-key primitive, trying to attack it (a.k.a cryptanalysis) is the main approach we have to assess its security. Particular care shall be taken to the analysis of statistical attacks, which are among the most efficient approaches known to date. The
two most famous examples are differential and linear cryptanalysis, but many other variants were proposed afterwards, including the differential-linear technique and the boomerang attacks, to cite a few.

Unfortunately, no efficient ways exist to identify statistical defects, and the generic approach is to study each of the small components to deduce how the property evolves round after round through the primitive. On the bright side, several techniques have been recently introduced to automate this process with computer programs, saving cryptanalysts from having to do it manually. It however remains imperfect as the descriptions of the problem in the programs (known as the modelling techniques) are generally simplifications that are not always accurate, and are often unsuitable for lightweight constructions.


PhD proposal

In recent years many new iterative frameworks that aim at capturing more accurately the probability have been proposed. While their theory is in general sound, they are harder to use, and it is less clear how to efficiently find distinguishers with these approaches.
The aim of this PhD is to propose new modelling techniques for automated search of symmetric distinguishers and attacks.

Principales activités

The core activities of this PhD thesis include:

- Study the state-of-the-art in the modelling of attacks and the recents theoretical frameworks giving estimates of the probability of distinguishers,
- Develop new methods for modelling the search of efficient parameters for a cryptanalysis, 
- Write and publish the scientific results in scientific journals and conferences.

Compétences

- Solid knowledge in the domain of cryptography. 
- Solid programming skills (Python, Sagemath, C).
- Strong communication abilities.
- Fluency in English (written and spoken)

Avantages

  • Subsidized meals
  • Partial reimbursement of public transport costs
  • Leave: 7 weeks of annual leave + 10 extra days off due to RTT (statutory reduction in working hours) + possibility of exceptional leave (sick children, moving home, etc.)
  • Possibility of teleworking (after 6 months of employment) and flexible organization of working hours
  • Professional equipment available (videoconferencing, loan of computer equipment, etc.)
  • Social, cultural and sports events and activities
  • Access to vocational training
  • Social security coverage

Rémunération

2200€ gross/month