Description
An algebraic attack is a method for cryptanalysis which is based on finding and solving a system of nonlinear equations. Recently, algebraic attacks where found helpful in cryptanalysing stream ciphers based on linear feedback shift registers. The efficiency of these attacks greatly depends on the degree of the nonlinear equations.<br/> At Crypto 2003, Courtois proposed fast algebraic attacks. The main idea is to decrease the degree of the equations using a precomputation algorithm. Unfortunately, the correctness of the precomputation algorithm was neither proven, nor was it obvious in all cases. In the first part of the talk, an introduction to fast algebraic attacks is given. In the second part, the results introduced in the paper "Improving Fast Algebraic Attacks" (FSE 2004) are presented in more detail. This includes the missing proof of correctness and an improvement of the precomputation algorithm. All aspects will be illustrated on the Bluetooth keystream generator E_0.
Prochains exposés
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Post-Quantum Public-Key Pseudorandom Correlation Functions for OT
Orateur : Mahshid Riahinia - ENS, CNRS
Public-Key Pseudorandom Correlation Functions (PK-PCF) are an exciting recent primitive introduced to enable fast secure computation. Despite significant advances in the group-based setting, success in the post-quantum regime has been much more limited. In this talk, I will introduce an efficient lattice-based PK-PCF for the string OT correlation. At the heart of our result lie several technical[…] -
Predicting Module-Lattice Reduction
Orateur : 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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