13,528 research outputs found
Deterministic Channel Design for Minimum Leakage
This work explores the problem of designing a channel that leaks the least amount of information while respecting a set of operational constraints. This paper focuses on deterministic channels and deterministic solutions. This setting is relevant because most programs and many channel design problems are naturally modelled by deterministic channels. Moreover, the setting is also relevant when considering an attacker who can observe many outputs of an arbitrary channel while the secret input stays the same: when the number of observations is arbitrarily large, the channel of minimal leakage is deterministic. The deterministic channel design problem has different solutions depending on which leakage measure is chosen. The problem is shown to be NP-hard in general. However, for a particular class of constraints, called k-complete hypergraph constraints, a greedy algorithm is shown to provide the optimal solution for a wide class of leakage measures
Asymmetric Quantum Dialogue in Noisy Environment
A notion of asymmetric quantum dialogue (AQD) is introduced. Conventional
protocols of quantum dialogue are essentially symmetric as both the users
(Alice and Bob) can encode the same amount of classical information. In
contrast, the scheme for AQD introduced here provides different amount of
communication powers to Alice and Bob. The proposed scheme, offers an
architecture, where the entangled state and the encoding scheme to be shared
between Alice and Bob depends on the amount of classical information they want
to exchange with each other. The general structure for the AQD scheme has been
obtained using a group theoretic structure of the operators introduced in
(Shukla et al., Phys. Lett. A, 377 (2013) 518). The effect of different types
of noises (e.g., amplitude damping and phase damping noise) on the proposed
scheme is investigated, and it is shown that the proposed AQD is robust and
uses optimized amount of quantum resources.Comment: 11 pages, 2 figure
DR.SGX: Hardening SGX Enclaves against Cache Attacks with Data Location Randomization
Recent research has demonstrated that Intel's SGX is vulnerable to various
software-based side-channel attacks. In particular, attacks that monitor CPU
caches shared between the victim enclave and untrusted software enable accurate
leakage of secret enclave data. Known defenses assume developer assistance,
require hardware changes, impose high overhead, or prevent only some of the
known attacks. In this paper we propose data location randomization as a novel
defensive approach to address the threat of side-channel attacks. Our main goal
is to break the link between the cache observations by the privileged adversary
and the actual data accesses by the victim. We design and implement a
compiler-based tool called DR.SGX that instruments enclave code such that data
locations are permuted at the granularity of cache lines. We realize the
permutation with the CPU's cryptographic hardware-acceleration units providing
secure randomization. To prevent correlation of repeated memory accesses we
continuously re-randomize all enclave data during execution. Our solution
effectively protects many (but not all) enclaves from cache attacks and
provides a complementary enclave hardening technique that is especially useful
against unpredictable information leakage
Privacy Against Statistical Inference
We propose a general statistical inference framework to capture the privacy
threat incurred by a user that releases data to a passive but curious
adversary, given utility constraints. We show that applying this general
framework to the setting where the adversary uses the self-information cost
function naturally leads to a non-asymptotic information-theoretic approach for
characterizing the best achievable privacy subject to utility constraints.
Based on these results we introduce two privacy metrics, namely average
information leakage and maximum information leakage. We prove that under both
metrics the resulting design problem of finding the optimal mapping from the
user's data to a privacy-preserving output can be cast as a modified
rate-distortion problem which, in turn, can be formulated as a convex program.
Finally, we compare our framework with differential privacy.Comment: Allerton 2012, 8 page
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