1,044,772 research outputs found
Reuse It Or Lose It: More Efficient Secure Computation Through Reuse of Encrypted Values
Two-party secure function evaluation (SFE) has become significantly more
feasible, even on resource-constrained devices, because of advances in
server-aided computation systems. However, there are still bottlenecks,
particularly in the input validation stage of a computation. Moreover, SFE
research has not yet devoted sufficient attention to the important problem of
retaining state after a computation has been performed so that expensive
processing does not have to be repeated if a similar computation is done again.
This paper presents PartialGC, an SFE system that allows the reuse of encrypted
values generated during a garbled-circuit computation. We show that using
PartialGC can reduce computation time by as much as 96% and bandwidth by as
much as 98% in comparison with previous outsourcing schemes for secure
computation. We demonstrate the feasibility of our approach with two sets of
experiments, one in which the garbled circuit is evaluated on a mobile device
and one in which it is evaluated on a server. We also use PartialGC to build a
privacy-preserving "friend finder" application for Android. The reuse of
previous inputs to allow stateful evaluation represents a new way of looking at
SFE and further reduces computational barriers.Comment: 20 pages, shorter conference version published in Proceedings of the
2014 ACM SIGSAC Conference on Computer and Communications Security, Pages
582-596, ACM New York, NY, US
Tail estimates for the Brownian excursion area and other Brownian areas
Several Brownian areas are considered in this paper: the Brownian excursion
area, the Brownian bridge area, the Brownian motion area, the Brownian meander
area, the Brownian double meander area, the positive part of Brownian bridge
area, the positive part of Brownian motion area. We are interested in the
asymptotics of the right tail of their density function. Inverting a double
Laplace transform, we can derive, in a mechanical way, all terms of an
asymptotic expansion. We illustrate our technique with the computation of the
first four terms. We also obtain asymptotics for the right tail of the
distribution function and for the moments. Our main tool is the two-dimensional
saddle point method.Comment: 34 page
Experimental Realization of the Deutsch-Jozsa Algorithm with a Six-Qubit Cluster State
We describe the first experimental realization of the Deutsch-Jozsa quantum
algorithm to evaluate the properties of a 2-bit boolean function in the
framework of one-way quantum computation. For this purpose a novel two-photon
six-qubit cluster state was engineered. Its peculiar topological structure is
the basis of the original measurement pattern allowing the algorithm
realization. The good agreement of the experimental results with the
theoretical predictions, obtained at 1kHz success rate, demonstrate the
correct implementation of the algorithm.Comment: 5 pages, 2 figures, RevTe
On the detection of nearly optimal solutions in the context of single-objective space mission design problems
When making decisions, having multiple options available for a possible realization of the same project can be advantageous. One way to increase the number of interesting choices is to consider, in addition to the optimal solution x*, also nearly optimal or approximate solutions; these alternative solutions differ from x* and can be in different regions – in the design space – but fulfil certain proximity to its function value f(x*). The scope of this article is the efficient computation and discretization of the set E of e–approximate solutions for scalar optimization problems. To accomplish this task, two strategies to archive and update the data of the search procedure will be suggested and investigated. To make emphasis on data storage efficiency, a way to manage significant and insignificant parameters is also presented. Further on, differential evolution will be used together with the new archivers for the computation of E. Finally, the behaviour of the archiver, as well as the efficiency of the resulting search procedure, will be demonstrated on some academic functions as well as on three models related to space mission design
A type system for Continuation Calculus
Continuation Calculus (CC), introduced by Geron and Geuvers, is a simple
foundational model for functional computation. It is closely related to lambda
calculus and term rewriting, but it has no variable binding and no pattern
matching. It is Turing complete and evaluation is deterministic. Notions like
"call-by-value" and "call-by-name" computation are available by choosing
appropriate function definitions: e.g. there is a call-by-value and a
call-by-name addition function. In the present paper we extend CC with types,
to be able to define data types in a canonical way, and functions over these
data types, defined by iteration. Data type definitions follow the so-called
"Scott encoding" of data, as opposed to the more familiar "Church encoding".
The iteration scheme comes in two flavors: a call-by-value and a call-by-name
iteration scheme. The call-by-value variant is a double negation variant of
call-by-name iteration. The double negation translation allows to move between
call-by-name and call-by-value.Comment: In Proceedings CL&C 2014, arXiv:1409.259
2D Quantum Gravity on Compact Riemann Surfaces and Two-Loop Partition Function: Circumventing the c=1 Barrier?
We study two-dimensional quantum gravity on arbitrary genus Riemann surfaces
in the Kaehler formalism where the basic quantum field is the (Laplacian of
the) Kaehler potential. We do a careful first-principles computation of the
fixed-area partition function up to and including all two-loop
contributions. This includes genuine two-loop diagrams as determined by the
Liouville action, one-loop diagrams resulting from the non-trivial measure on
the space of metrics, as well as one-loop diagrams involving various
counterterm vertices. Contrary to what is often believed, several such
counterterms, in addition to the usual cosmological constant, do and must
occur. We consistently determine the relevant counterterms from a one-loop
computation of the full two-point Green's function of the Kaehler field.
Throughout this paper we use the general spectral cutoff regularization
developed recently and which is well-suited for multi-loop computations on
curved manifolds. At two loops, while all "unwanted" contributions to correctly cancel, it appears that the finite coefficient of does depend on the finite parts of certain counterterm coefficients,
i.e. on the finite renormalization conditions one has to impose. There exists a
choice that reproduces the famous KPZ-scaling, but it seems to be only one
consistent choice among others. Maybe, this hints at the possibility that other
renormalization conditions could eventually provide a way to circumvent the
famous barrier.Comment: 54 page
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