Description
Access to encrypted data is often “all-or-nothing” : either one has to decrypt everything, or one cannot read anything. Following Gentry’s work in 2009, fully homomorphic encryption has gained more and more attention, in particular because it allows more flexibility on encrypted data access and process. It is now possible to evaluate functions on encrypted data and get only the result – encrypted as well. This possibility offers numerous applications, especially when building a trustworthy cloud provider where the server cannot access the users’ data. It theoretically reconciles a rich user experience with protection of her sensible data. However, efficiency of fully homomorphic encryption remains seriously undermined by a very costly procedure: the “bootstrapping”. In this talk, we will show how to use graph problems and integer linear programming in order to determine the minimal number of bootstrappings necessary to correctly evaluate a circuit over encrypted data. Our method allows significant efficiency gains in the evaluation process, saving up to 70% bootstrappings calls. This is a joint work with Bastien Vialla.
Prochains exposés
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Verification of Rust Cryptographic Implementations with Aeneas
Orateur : Aymeric Fromherz - Inria
From secure communications to online banking, cryptography is the cornerstone of most modern secure applications. Unfortunately, cryptographic design and implementation is notoriously error-prone, with a long history of design flaws, implementation bugs, and high-profile attacks. To address this issue, several projects proposed the use of formal verification techniques to statically ensure the[…] -
On the average hardness of SIVP for module lattices of fixed rank
Orateur : Radu Toma - Sorbonne Université
In joint work with Koen de Boer, Aurel Page, and Benjamin Wesolowski, we study the hardness of the approximate Shortest Independent Vectors Problem (SIVP) for random module lattices. We use here a natural notion of randomness as defined originally by Siegel through Haar measures. By proving a reduction, we show it is essentially as hard as the problem for arbitrary instances. While this was[…] -
Endomorphisms via Splittings
Orateur : Min-Yi Shen - No Affiliation
One of the fundamental hardness assumptions underlying isogeny-based cryptography is the problem of finding a non-trivial endomorphism of a given supersingular elliptic curve. In this talk, we show that the problem is related to the problem of finding a splitting of a principally polarised superspecial abelian surface. In particular, we provide formal security reductions and a proof-of-concept[…]-
Cryptography
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