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INRIA, Evaluation of Theme Sym B INRIA, Evaluation of Theme Sym B Project-team CODES November 2006 Project-team title: CODES Scientific leader: Nicolas Sendrier Research center: Rocquencourt 1 Personnel Personnel (March 2002) Misc. INRIA CNRS University Total DR (1) / Professors 1 1 2 CR (2) / Assistant Professors 4 4 Permanent Engineers (3) Temporary Engineers (4) PhD Students 5 1 3 9 Post-Doc. 1 1 Total 5 6 5 16 External Collaborators 6 4 9 Visitors (> 1 month) (1) “Senior Research Scientist (Directeur de Recherche)” (2) “Junior Research Scientist (Charg´ede Recherche)” (3) “Civil servant (CNRS, INRIA, ...)” (4) “Associated with a contract (Ing´enieurExpert or Ing´enieurAssoci´e)” Personnel (November 2006) Misc. INRIA CNRS University Total DR / Professors 3 3 CR / Assistant Professor 2 2 Permanent Engineer Temporary Engineer PhD Students 6 4 1 11 Post-Doc. 1 1 Total 7 9 1 17 External Collaborators 5 2 8 Visitors (> 1 month) 1 Changes in staff DR / Professors Misc. INRIA CNRS University total CR / Assistant Professors Arrival Leaving Comments: Claude Carlet was moved from “Staff” to “External Collaborators” be- cause of his involvement at the University Paris 8. Nicolas Sendrier and Anne Canteaut have been promoted from CR to DR during the period. Jean-Pierre Tillich was on a temporary INRIA CR position (“d´etachement”) and has now a permanent INRIA CR position. The following researchers had a temporary position in the group during the period: • Enes Pasalic (Post-doc. in 2003) • Emmanuel Cadic (Post-doc. in 2004) • Avishek Adhikari (Post-doc. in 2004/2005) • Michael Quisquater (Post-doc. in 2005/2006) • Marine Minier (“Ing´enieurExpert” in 2004/2005) • Fabien Galand (“Ing´enieurExpert” in 2005/2006) Current composition of the project-team (November 2006): • Anne Canteaut, DR INRIA • Pascale Charpin, DR INRIA • Nicolas Sendrier, DR INRIA • Daniel Augot, CR INRIA • Jean-Pierre Tillich, CR INRIA • Deepak Dalai, Post-doc., French ministry of research scholarship (starting 12/2006) • Bhaskar Biswas, PhD Student, INRIA scholarship • Thomas Camara, PhD Student, MERT scholarship • Christophe Chabot, PhD Student, DGA scholarship • Mathieu Cluzeau, PhD Student, DGA scholarship • Fr´ed´ericDidier, PhD Student, AMN scholarship • C´edricFaure, PhD Student, AMN scholarship • Yann Laigle-Chapuy, PhD Student, AMN scholarship • C´edricLauradoux, PhD Student, INRIA scholarship • Maria Naya Plasencia, PhD Student, INRIA scholarship 2 • Andrea R¨ock, PhD Student, INRIA scholarship • Bassem Sakkour, PhD Student, ENSTA scholarship • Claude Carlet, External Collaborator, Professor, University Paris 8 • Guy Chass´e,External Collaborator, Professor, Ecole´ des Mines de Nantes • Fran¸coiseLevy-dit-Vehel, External Collaborator, Professor, ENSTA • Pierre Loidreau, External Collaborator, Professor, ENSTA • Matthieu Finiasz, External Collaborator, Post-doc., EPFL, Switzerland • Grigory Kabatianskiy, External Collaborator, Researcher IPIT, Russia • Harold Ollivier, External Collaborator, French ministry of finances • Ayoub Otmani, External Collaborator, Assistant Professor, University of Caen Current position of former project-team members (including PhD stu- dents during the period): • Gregory Olocco, Prospective Department Manager, Air Liquide, Paris • C´edricTavernier, R&D engineer, Thal`es,Colombes • Matthieu Finiasz, Post-doc., EPFL, Switzerland ∗ • Harold Ollivier, French ministry of finances ∗ • Fabien Galand, Post-doc., IRISA, Rennes • Magali Bardet, Assistant Professor, University of Rouen • Carmen Nedeloaia, ATER, University of Paris 8 • Marine Minier, Assistant Professor, INSA Lyon • Marion Videau, Assistant Professor, University of Nancy • Ludovic Perret, Post-doc., UCL, Louvain, Belgium • Michael Quisquater, Assistant Professor, University of Versailles Saint-Quentin • Raghav Bhaskar, Post-doc., Microsoft Research, Bangalore, India ∗ also listed as external collaborators. Last INRIA enlistments • Nicolas Sendrier, DR2, 2003 • Jean-Pierre Tillich, CR1, 2003 • Anne Canteaut, DR2, 2006 All three were already in the research staff in March 2002, with a different status. 3 Other comments: Nicolas Sendrier, with Daniel Augot as vice-leader, replaced Pascale Charpin as scientific leader in 2002. 2 Work progress 2.1 Keywords Cryptography, Symmetric cryptography, Asymmetric cryptography, Cryptanalysis, Alge- braic coding theory, Iterative decoding, Discrete mathematics, Boolean functions, Code recognition 2.2 Context and overall goal of the project The research work of the team project CODES is mostly devoted to the design and analysis of cryptographic algorithms through the study of the discrete structures that they involve. Our multiple competences in mathematics and algorithmics have allowed us to address a large variety of problems related to information protection. Most of our work mix fundamental aspects (study of mathematical objects) and practical aspects (cryptanalysis, design of algorithms, implementations). Our application domains are mainly cryptography, error correcting codes and code recognition (“electronic war”). Even though these domains may appear different, our ap- proach is unified. For instance, decoding techniques are used to design new error correcting codes, but also new cryptanalysis. Code recognition (that is recognizing an unknown cod- ing scheme from a sample), is very similar to stream cipher cryptanalysis. Our research is driven by the belief that discrete mathematics and algorithmics of finite structure form the scientific core of (algorithmic) data protection. We think that our past results justify this approach and we feel that, with the evolution of cryptographic research, more and more researchers will follow this path. Our purpose is not to present more evidence that algebraic coding theory or discrete mathematics can be “applied to” cryptography, but to convince that these fields belong the the scientific foundations of cryptography or more generally data protection techniques. 2.3 Objectives for the evaluation period The three objectives given in March 2002 were (in French) 1. Analyse formelle de la s´ecurit´edes syst`emes`aclef secr`ete; 2. Syst`emes`aclef publique fond´essur les codes ; 3. Cryptanalyse : exploitation de nouvelles techniques de d´ecodage, r´esolutiondes syst`emesalg´ebriques. There has been some minor changes with the actual work during the period, mainly: • The third objective is more oriented towards decoding. In March 2002, Jean-Pierre Tillich had a temporary CR1 position (on leave from University Paris 11). His recruitment on a permanent position, and the opportunity to work with France Telecom on iterative decoding has increased the importance of error correcting codes as an application domain for our work. 4 • A new topic has appeared through our collaboration with DGA, and Mathieu Cluzeau’s thesis: electronic war. Fundamentally, this domain uses cryptographic tools and even cryptographic results. This allowed us to easily include Mathieu’s contributions in the symmetric crypto and in the decoding subsections (objectives 1 and 3). 2.4 Security analysis of symmetric cryptosystems 2.4.1 Personnel - Anne Canteaut, DR INRIA, - Pascale Charpin, DR INRIA, - Avishek Adhikari (Post-doc), - Mathieu Cluzeau (PhD), - Fr´ed´ericDidier (PhD), - Yann Laigle-Chapuy (PhD), - C´edricLauradoux (PhD), - Marine Minier (“Ingenieur Expert”), - Maria Naya Plasencia (PhD), - Enes Pasalic (Post-doc), - Marion Videau (PhD), - Claude Carlet (external collaborator, Prof. Univ. Paris 8). 2.4.2 Project-team positioning From outside, it might appear that symmetric techniques become obsolete after the in- vention of public-key cryptography in the mid 1970’s. However, they are still widely used because they are the only ones that can achieve some major functionalities as high-speed or low-cost encryption, fast authentication, and efficient hashing. Today, we find symmet- ric algorithms in GSM mobile phones, in credit cards, in WLAN connections. Symmetric cryptology is a very active research area which is stimulated by a pressing industrial de- mand for low-cost implementations (in terms of power consumption, gate complexity...). Research in symmetric cryptography is obviously characterized by a sequence of de- fenses and attacks. But, each new dedicated attack against a given cryptosystem must be formalized, its scope must be analyzed and the structural properties which make it feasible must be highlighted. This approach is the only one which can lead to new design criteria and to the constructions of building blocks which guarantee to a provable resistance to the known attacks. However, such an analysis yields a practical system only if it includes the implementation requirements arising from the applications. Therefore, our work considers all aspects of the field, from the practical ones (new attacks, concrete specifications of new systems) to the most theoretical ones (study of the algebraic structure of underlying mathematical objects, definition of optimal objects). But, our purpose is to study these aspects not separately but as several sides of the same domain. This joint approach of the different aspects of symmetric cryptography is quite peculiar to our work. Several research teams are working in symmetric cryptography (see e.g. Fast Soft- ware Encryption which is an annual conference dedicated to symmetric encryption). The main peer or competitor groups are: Univ. of Bergen (T. Helleseth); France Telecom R& D (H. Gilbert, M. Robshaw); Lund University (T. Johansson); Ecole´ Polytechnique F´ed´eralede Lausanne (S. Vaudenay); Technion Haifa, Isra¨el(E. Biham);
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