543 résultats
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On the design and implementation of scalar multiplication algorithms
Orateur : Koray Karabina - Florida Atlantic University
Diffie-Hellman type key exchange protocols and standardized digital signature algorithms all benefit from efficient design and secure implementation of group exponentiation algorithms. This talk will focus on elliptic curve groups and scalar multiplication algorithms derived from differential addition chains. First, I will give a survey of algorithms, and then I will present some recent[…] -
Learning Strikes Again: the Case of the DRS Signature Scheme
Orateur : Yu Yang - CWI Amsterdam
Lattice signature schemes generally require particular care when it comes to preventing secret information from leaking through signature transcript. For example, the Goldreich-Goldwasser-Halevi (GGH) signature scheme and the NTRUSign scheme were completely broken by the parallelepiped-learning attack of Nguyen and Regev (Eurocrypt 2006). Several heuristic countermeasures were also shown[…] -
Practical Strategy-Resistant Privacy-Preserving Elections
Orateur : Quentin Santos - Orange
Recent advances in cryptography promise to let us run com- plex algorithms in the encrypted domain. However, these results are still mostly theoretical since the running times are still much larger than their equivalents in the plaintext domain. In this context, Majority Judgment is a recent proposal for a new voting system with several interesting practical advantages, but which implies a more[…] -
Zero-Knowledge Argument for Matrix-Vector Relations and Lattice-Based Group Encryption
Orateur : Fabrice Mouhartem - ENS Lyon
Group encryption (GE) is the natural encryption analogue of group signatures in that it allows verifiably encrypting messages for some anonymous member of a group while providing evidence that the receiver is a properly certified group member. Should the need arise, an opening authority is capable of identifying the receiver of any ciphertext. As intro- duced by Kiayias, Tsiounis and Yung […] -
Key Reinstallation Attacks: Forcing Nonce Reuse in WPA2
Orateur : Mathy Vanhoef - KU-Leuven
We introduce key reinstallation attacks (KRACKs). These attacks abuse features of a protocol to reinstall an already in-use key, thereby resetting nonces and/or replay counters associated to this key. We show that our novel attack technique breaks several handshakes that are used in a WPA2-protected network.<br/> All protected Wi-Fi networks use the 4-way handshake to generate fresh session keys.[…] -
Grost Distinguishing Attack: A new rebound attack of an AES-like permutation
Orateur : Victor Cauchois - DGA et IRMAR
Grostl est une fonction de hachage finaliste de la compétition SHA-3. Elle est dotée d'une preuve de sécurité qui assure sa résistance aux attaques en collision, pré-image et seconde pré-image sous l'hypothèse que deux permutations internes sont idéales. Ces permutations, 14 tours d'un SPN, calques de l'AES, présentent une structure sensible aux attaques rebond. Ces attaques sont des attaques[…]