Êtes-vous un étudiant de l'EPFL à la recherche d'un projet de semestre?

Travaillez avec nous sur des projets en science des données et en visualisation, et déployez votre projet sous forme d'application sur GraphSearch.

Découvrez-en plus sur les applications Graph.

Concept

National Security Agency

La National Security Agency (NSA, « Agence nationale de la sécurité ») est un organisme gouvernemental du département de la Défense des États-Unis, responsable du renseignement d'origine électromagnétique et de la sécurité des systèmes d'information du gouvernement américain. Le Central Security Service (CSS) est une agence qui loge dans les mêmes bureaux que la NSA et qui a été créée dans le but de coordonner les efforts des sections de cryptographie de la NSA et de l'armée des États-Unis. Missions La NSA/CSS est chargée de diriger les activités de cryptologie du gouvernement américain. La cryptologie, selon sa définition, comprend deux missions principales :

Signals Intelligence (SIGINT), c'est-à-dire le renseignement d'origine électromagnétique ;
Information Assurance (IA), la sécurité des systèmes de communications et de traitement des données.

Par ailleurs elle rend techniquement possibles les Computer Network Operations (CNO), c'est-à-dire les opérations d'att

À propos de ce résultat

Cette page est générée automatiquement et peut contenir des informations qui ne sont pas correctes, complètes, à jour ou pertinentes par rapport à votre recherche. Il en va de même pour toutes les autres pages de ce site. Veillez à vérifier les informations auprès des sources officielles de l'EPFL.

Publications associées (6)

Publications associées

Chargement

Personnes associées (1)

Personnes associées

Chargement

Unités associées (1)

Unités associées

Chargement

Concepts associés (135)

Concepts associés

Chargement

Cours associés (7)

Cours associés

Chargement

Séances de cours associées (12)

Séances de cours associées

Chargement

Practical Private Range Search Revisited

Ioannis Demertzis, Odysseas Papapetrou

We consider a data owner that outsources its dataset to an untrusted server. The owner wishes to enable the server to answer range queries on a single attribute, without compromising the privacy of the data and the queries. There are several schemes on "practical" private range search (mainly in Databases venues) that attempt to strike a trade-off between efficiency and security. Nevertheless, these methods either lack provable security guarantees, or permit unacceptable privacy leakages. In this paper, we take an interdisciplinary approach, which combines the rigor of Security formulations and proofs with efficient Data Management techniques. We construct a wide set of novel schemes with realistic security/performance trade-offs, adopting the notion of Searchable Symmetric Encryption (SSE) primarily proposed for keyword search. We reduce range search to multi-keyword search using range covering techniques with tree-like indexes. We demonstrate that, given any secure SSE scheme, the challenge boils down to (i) formulating leakages that arise from the index structure, and (ii) minimizing false positives incurred by some schemes under heavy data skew. We analytically detail the superiority of our proposals over prior work and experimentally confirm their practicality.

2016

Chargement

Practical Private Range Search in Depth

Ioannis Demertzis, Odysseas Papapetrou

We consider a data owner that outsources its dataset to an untrusted server. The owner wishes to enable the server to answer range queries on a single attribute, without compromising the privacy of the data and the queries. There are several schemes on “practical” private range search (mainly in database venues) that attempt to strike a trade-off between efficiency and security. Nevertheless, these methods either lack provable security guarantees or permit unacceptable privacy leakages. In this article, we take an interdisciplinary approach, which combines the rigor of security formulations and proofs with efficient data management techniques. We construct a wide set of novel schemes with realistic security/performance trade-offs, adopting the notion of Searchable Symmetric Encryption (SSE), primarily proposed for keyword search. We reduce range search to multi-keyword search using range-covering techniques with tree-like indexes, and formalize the problem as Range Searchable Symmetric Encryption (RSSE). We demonstrate that, given any secure SSE scheme, the challenge boils down to (i) formulating leakages that arise from the index structure and (ii) minimizing false positives incurred by some schemes under heavy data skew. We also explain an important concept in the recent SSE bibliography, namely locality, and design generic and specialized ways to attribute locality to our RSSE schemes. Moreover, we are the first to devise secure schemes for answering range aggregate queries, such as range sums and range min/max. We analytically detail the superiority of our proposals over prior work and experimentally confirm their practicality.

2018

Chargement

Authenticated Encryption with Variable Stretch

Reza Reyhanitabar, Serge Vaudenay, Damian Vizár

In conventional authenticated-encryption (AE) schemes, the ciphertext expansion, a.k.a.stretch or tag length, is a constant or a parameter of the scheme that must be fixed per key. However, using variable-length tags per key can be desirable in practice or may occur as a result of a misuse. The RAE definition by Hoang, Krovetz, and Rogaway (Eurocrypt 2015), aiming at the best-possible AE security, supports variable stretch among other strong features, but achieving the RAE goal incurs a particular inefficiency: neither encryption nor decryption can be online. The problem of enhancing the well-established nonce-based AE (nAE) model and the standard schemes thereof to support variable tag lengths per key, without sacrificing any desirable functional and efficiency properties such as online encryption, has recently regained interest as evidenced by extensive discussion threads on the CFRG forum and the CAESAR competition. Yet there is a lack of formal definition for this goal. First, we show that several recently proposed heuristic measures trying to augment the known schemes by inserting the tag length into the nonce and/or associated data fail to deliver any meaningful security in this setting. Second, we provide a formal definition for the notion of nonce-based variable-stretch AE (nvAE) as a natural extension to the traditional nAE model. Then, we proceed by showing a second modular approach to formalizing the goal by combining the nAE notion and a new property we call key-equivalent separation by stretch (kess). It is proved that (after a mild adjustment to the syntax) any nAE scheme which additionally fulfills the kess property will achieve the nvAE goal. Finally, we show that the nvAE goal is efficiently and provably achievable; for instance, by simple tweaks to off-the-shelf schemes such as OCB.

Springer-Verlag Berlin2016

Chargement

Central Intelligence Agency

La Central Intelligence Agency (CIA, « agence centrale de renseignement » en français), fondée en 1947 par le National Security Act, est l'une des agences de renseignement les plus connues des États

Cryptographie

thumb|La machine de Lorenz utilisée par les nazis durant la Seconde Guerre mondiale pour chiffrer les communications militaires de haut niveau entre Berlin et les quartiers-généraux des différentes ar

Attentats du 11 septembre 2001

Les attentats du (communément appelés , 9/11 en anglais) sont quatre attentats-suicides islamistes perpétrés le même jour aux États-Unis et provoquant la mort de , à Manhattan à New York, à Arlingt

CS-523: Advanced topics on privacy enhancing technologies

This advanced course will provide students with the knowledge to tackle the design of privacy-preserving ICT systems. Students will learn about existing technologies to prect privacy, and how to evaluate the protection they provide.

COM-301: Computer security

This is an introductory course to computer security and privacy. Its goal is to provide students with means to reason about security and privacy problems, and provide them with tools to confront them.

COM-402: Information security and privacy

This course provides an overview of information security and privacy topics. It introduces students to the knowledge and tools they will need to deal with the security/privacy challenges they are likely to encounter in today's Big Data world. The tools are illustrated with relevant applications.