522 résultats
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TBD (To be decided closer to the date of the talk)
Orateur : Lisa Kohl - CWI
TBD (To be decided closer to the date of the talk) -
Ind-cpa-d insecurity of approximate and exact homomorphic encryption schemes
Orateur : Elias Suvanto - Cryptolab
Fully Homomorphic Encryption enables the evaluation of arbitrary circuits over encrypted data while maintaining the confidentiality of the underlying messages. It greatly enhances functionality but also comes with security challenges for some applications like Threshold FHE. While the standard IND-CPA security is sufficient against honest but curious adversaries, a stronger security notion called[…] -
Recent advances in post-quantum signatures based on the MPC-in-the-Head paradigm
Orateur : Thibauld Feneuil - CryptoExperts
Zero-knowledge proofs of knowledge are useful tools for designing signature schemes. Among the existing techniques, the MPC-in-Head (MPCitH) paradigm provides a generic framework to build quantum-resilient proofs using techniques from secure multiparty computation. This paradigm has recently been improved in a series of works which makes it an effective and versatile tool. In this talk, I will[…] -
Updatable Public Key Encryption with Lattices
Orateur : Calvin Abou-Haidar - ENS Lyon
Updatable public key encryption has recently been introduced as a so- lution to achieve forward-security in the context of secure group messaging without hurting efficiency, but so far, no efficient lattice-based instantia- tion of this primitive is known. In this work, we construct the first LWE-based UPKE scheme with polynomial modulus-to-noise rate, which is CPA-secure in the standard model. At[…] -
Quantum Linear Key-recovery Attacks Using the QFT
Orateur : André Schrottenloher - IRISA
The Quantum Fourier Transform is a fundamental tool in quantum cryptanalysis, not only as the building block of Shor's algorithm, but also in attacks against symmetric cryptosystems. Indeed, hidden shift algorithms such as Simon's (FOCS 1994), which rely on the QFT, have been used to obtain attacks on some very specific block cipher structures. The Fourier Transform is also used in classical[…] -
Shorter Lattice-Based Fiat-Shamir Signatures
Orateur : Julien Devevey - ANSSI
We present HAETAE (Hyperball bimodAl modulE rejecTion signAture schemE), a new lattice-based signature scheme, which we submitted to the Korean Post-Quantum Cryptography Competition for standardization. Like the NIST-selected Dilithium signature scheme, HAETAE is based on the Fiat-Shamir with Aborts paradigm, but our design choices target an improved complexity/compactness compromise that is[…]