350,603 research outputs found
Complexity of Secure Sets
A secure set in a graph is defined as a set of vertices such that for any
the majority of vertices in the neighborhood of belongs to
. It is known that deciding whether a set is secure in a graph is
co-NP-complete. However, it is still open how this result contributes to the
actual complexity of deciding whether for a given graph and integer , a
non-empty secure set for of size at most exists. In this work, we
pinpoint the complexity of this problem by showing that it is
-complete. Furthermore, the problem has so far not been subject to
a parameterized complexity analysis that considers structural parameters. In
the present work, we prove that the problem is -hard when parameterized
by treewidth. This is surprising since the problem is known to be FPT when
parameterized by solution size and "subset problems" that satisfy this property
usually tend to be FPT for bounded treewidth as well. Finally, we give an upper
bound by showing membership in XP, and we provide a positive result in the form
of an FPT algorithm for checking whether a given set is secure on graphs of
bounded treewidth.Comment: 28 pages, 9 figures, short version accepted at WG 201
Range-Based Set Reconciliation and Authenticated Set Representations
Range-based set reconciliation is a simple approach to efficiently computing
the union of two sets over a network, based on recursively partitioning the
sets and comparing fingerprints of the partitions to probabilistically detect
whether a partition requires further work. Whereas prior presentations of this
approach focus on specific fingerprinting schemes for specific use-cases, we
give a more generic description and analysis in the broader context of set
reconciliation. Precisely capturing the design space for fingerprinting schemes
allows us to survey for cryptographically secure schemes. Furthermore, we
reduce the time complexity of local computations by a logarithmic factor
compared to previous publications. In investigating secure associative hash
functions, we open up a new class of tree-based authenticated data structures
which need not prescribe a deterministic balancing scheme
Private and Oblivious Set and Multiset Operations
Privacy-preserving set operations, and set intersection in particular, are
a popular research topic. Despite a large body of literature, the great
majority of the available solutions are two-party protocols and are not
composable. In this work we design a comprehensive suite of secure
multi-party protocols for set and multiset operations that are
composable, do not assume any knowledge of the sets by the parties
carrying out the secure computation, and can be used for secure
outsourcing. All of our protocols have communication and computation
complexity of for sets or multisets of size , which
compares favorably with prior work. Furthermore, we are not aware of any
results that realize composable operations. Our protocols are secure in
the information theoretic sense and are designed to minimize the round
complexity. Practicality of our solutions is shown through experimental
results
Improved Secure Efficient Delegated Private Set Intersection
Private Set Intersection (PSI) is a vital cryptographic technique used for
securely computing common data of different sets. In PSI protocols, often two
parties hope to find their common set elements without needing to disclose
their uncommon ones. In recent years, the cloud has been playing an influential
role in PSI protocols which often need huge computational tasks. In 2017, Abadi
et al. introduced a scheme named EO-PSI which uses a cloud to pass on the main
computations to it and does not include any public-key operations. In EO-PSI,
parties need to set up secure channels beforehand; otherwise, an attacker can
easily eavesdrop on communications between honest parties and find private
information. This paper presents an improved EO-PSI scheme which has the edge
on the previous scheme in terms of privacy and complexity. By providing
possible attacks on the prior scheme, we show the necessity of using secure
channels between parties. Also, our proposed protocol is secure against passive
attacks without having to have any secure channels. We measure the protocol's
overhead and show that computational complexity is considerably reduced and
also is fairer compared to the previous scheme.Comment: 6 pages, presented in proceedings of the 28th Iranian Conference on
Electrical Engineering (ICEE 2020). Final version of the paper has been adde
Unconditionally Secure Multiparty Computation for Symmetric Functions with Low Bottleneck Complexity
Bottleneck complexity is an efficiency measure of secure multiparty computation (MPC) introduced by Boyle et al. (ICALP 2018) to achieve load-balancing. Roughly speaking, it is defined as the maximum communication complexity required by any player within the protocol execution. Since it is impossible to achieve sublinear bottleneck complexity in the number of players for all functions, a prior work constructed MPC protocols with low bottleneck complexity for specific functions including the AND function and general symmetric functions. However, the previous protocol for a symmetric function needs to assume a computational primitive of garbled circuits. Its unconditionally secure variant has exponentially large bottleneck complexity in the depth of an arithmetic formula computing the function, which limits the class of symmetric functions the protocol can compute with sublinear bottleneck complexity in . In this paper, we propose for the first time unconditionally secure MPC protocols computing any symmetric function with sublinear bottleneck complexity in . Our first protocol is an application of the one-time truth-table protocol by Ishai et al. (TCC 2013). We devise a novel technique to express the truth-table as an array of two or higher dimensions and obtain two other protocols with better trade-offs. We also propose an unconditionally secure protocol with lower bottleneck complexity tailored to the AND function. It avoids pseudorandom functions used by the previous protocol, preserving bottleneck complexity up to a logarithmic factor in . As an application, we construct an unconditionally secure protocol for private set intersection (PSI), which computes the intersection of players\u27 private sets. This is the first PSI protocol with sublinear bottleneck complexity in and to the best of our knowledge, there has been no such protocol even under cryptographic assumptions
A private set intersection protocol based on multi-party quantum computation for greatest common divisor
Private set intersection (PSI) is a cryptographic primitive that allows two or more parties to learn the intersection of their input sets and nothing else. In this paper, we present a private set intersection protocol based on a new secure multi-party quantum protocol for greatest common divisor (GCD). The protocol is mainly inspired by the recent quantum private set union protocol based on least common multiple by Liu, Yang, and Li. Performance analysis guarantees the correctness and it also shows that the proposed protocols are completely secure in semi-honest model. Moreover, the complexity is proven to be efficient (poly logarithmic) in the size of the input sets
A Logic Programming Approach to Knowledge-State Planning: Semantics and Complexity
We propose a new declarative planning language, called K, which is based on
principles and methods of logic programming. In this language, transitions
between states of knowledge can be described, rather than transitions between
completely described states of the world, which makes the language well-suited
for planning under incomplete knowledge. Furthermore, it enables the use of
default principles in the planning process by supporting negation as failure.
Nonetheless, K also supports the representation of transitions between states
of the world (i.e., states of complete knowledge) as a special case, which
shows that the language is very flexible. As we demonstrate on particular
examples, the use of knowledge states may allow for a natural and compact
problem representation. We then provide a thorough analysis of the
computational complexity of K, and consider different planning problems,
including standard planning and secure planning (also known as conformant
planning) problems. We show that these problems have different complexities
under various restrictions, ranging from NP to NEXPTIME in the propositional
case. Our results form the theoretical basis for the DLV^K system, which
implements the language K on top of the DLV logic programming system.Comment: 48 pages, appeared as a Technical Report at KBS of the Vienna
University of Technology, see http://www.kr.tuwien.ac.at/research/reports
Provenance Views for Module Privacy
Scientific workflow systems increasingly store provenance information about
the module executions used to produce a data item, as well as the parameter
settings and intermediate data items passed between module executions. However,
authors/owners of workflows may wish to keep some of this information
confidential. In particular, a module may be proprietary, and users should not
be able to infer its behavior by seeing mappings between all data inputs and
outputs. The problem we address in this paper is the following: Given a
workflow, abstractly modeled by a relation R, a privacy requirement \Gamma and
costs associated with data. The owner of the workflow decides which data
(attributes) to hide, and provides the user with a view R' which is the
projection of R over attributes which have not been hidden. The goal is to
minimize the cost of hidden data while guaranteeing that individual modules are
\Gamma -private. We call this the "secureview" problem. We formally define the
problem, study its complexity, and offer algorithmic solutions
EsPRESSo: Efficient Privacy-Preserving Evaluation of Sample Set Similarity
Electronic information is increasingly often shared among entities without
complete mutual trust. To address related security and privacy issues, a few
cryptographic techniques have emerged that support privacy-preserving
information sharing and retrieval. One interesting open problem in this context
involves two parties that need to assess the similarity of their datasets, but
are reluctant to disclose their actual content. This paper presents an
efficient and provably-secure construction supporting the privacy-preserving
evaluation of sample set similarity, where similarity is measured as the
Jaccard index. We present two protocols: the first securely computes the
(Jaccard) similarity of two sets, and the second approximates it, using MinHash
techniques, with lower complexities. We show that our novel protocols are
attractive in many compelling applications, including document/multimedia
similarity, biometric authentication, and genetic tests. In the process, we
demonstrate that our constructions are appreciably more efficient than prior
work.Comment: A preliminary version of this paper was published in the Proceedings
of the 7th ESORICS International Workshop on Digital Privacy Management (DPM
2012). This is the full version, appearing in the Journal of Computer
Securit
PS-TRUST: Provably Secure Solution for Truthful Double Spectrum Auctions
Truthful spectrum auctions have been extensively studied in recent years.
Truthfulness makes bidders bid their true valuations, simplifying greatly the
analysis of auctions. However, revealing one's true valuation causes severe
privacy disclosure to the auctioneer and other bidders. To make things worse,
previous work on secure spectrum auctions does not provide adequate security.
In this paper, based on TRUST, we propose PS-TRUST, a provably secure solution
for truthful double spectrum auctions. Besides maintaining the properties of
truthfulness and special spectrum reuse of TRUST, PS-TRUST achieves provable
security against semi-honest adversaries in the sense of cryptography.
Specifically, PS-TRUST reveals nothing about the bids to anyone in the auction,
except the auction result. To the best of our knowledge, PS-TRUST is the first
provably secure solution for spectrum auctions. Furthermore, experimental
results show that the computation and communication overhead of PS-TRUST is
modest, and its practical applications are feasible.Comment: 9 pages, 4 figures, submitted to Infocom 201
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