Description
In this talk, we will sum up our recent research results concerning the introduction of a new representation for FCSRs and for LFSRs. This matrix based representation allows to construct LFSRs and FCSRs with a more compact hardware representation and a quicker diffusion while preserving the usual and proven good properties (good periods, $\ell$-sequences, good statistical behaviors, etc.). Moreover, this new approach circumvents the weaknesses of the Fibonacci and Galois representations of FCSRs. We also show how to extend the LFSRs representation to a particular LFSR case called the windmill case. LFSRs are well-known primitives used in cryptography especially for stream cipher design. However they have some drawbacks when looking at their resistance against algebraic attacks because of their linearity. In the contrary, FCSRs are inherently resistant to algebraic attacks due to the non-linearity of the update function. Using the new representation, we propose two new stream ciphers based on the so-called "ring" FCSR representation. The first proposal called F-FCSR is dedicated to hardware applications whereas the second proposal called X-FCSR is designed for software purposes but is also efficient in hardware.
Next sessions
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Predicting Module-Lattice Reduction
Speaker : Paola de Perthuis - CWI
Is module-lattice reduction better than unstructured lattice reduction? This question was highlighted as `Q8' in the Kyber NIST standardization submission (Avanzi et al., 2021), as potentially affecting the concrete security of Kyber and other module-lattice-based schemes. Foundational works on module-lattice reduction (Lee, Pellet-Mary, Stehlé, and Wallet, ASIACRYPT 2019; Mukherjee and Stephens[…]-
Cryptography
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Séminaire C2 à INRIA Paris
Emmanuel Thomé et Pierrick Gaudry Rachelle Heim Boissier Épiphane Nouetowa Dung Bui Plus d'infos sur https://seminaire-c2.inria.fr/ -
Attacking the Supersingular Isogeny Problem: From the Delfs–Galbraith algorithm to oriented graphs
Speaker : Arthur Herlédan Le Merdy - COSIC, KU Leuven
The threat of quantum computers motivates the introduction of new hard problems for cryptography.One promising candidate is the Isogeny problem: given two elliptic curves, compute a “nice’’ map between them, called an isogeny.In this talk, we study classical attacks on this problem, specialised to supersingular elliptic curves, on which the security of current isogeny-based cryptography relies. In[…]-
Cryptography
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