31,945 research outputs found
Still Wrong Use of Pairings in Cryptography
Several pairing-based cryptographic protocols are recently proposed with a
wide variety of new novel applications including the ones in emerging
technologies like cloud computing, internet of things (IoT), e-health systems
and wearable technologies. There have been however a wide range of incorrect
use of these primitives. The paper of Galbraith, Paterson, and Smart (2006)
pointed out most of the issues related to the incorrect use of pairing-based
cryptography. However, we noticed that some recently proposed applications
still do not use these primitives correctly. This leads to unrealizable,
insecure or too inefficient designs of pairing-based protocols. We observed
that one reason is not being aware of the recent advancements on solving the
discrete logarithm problems in some groups. The main purpose of this article is
to give an understandable, informative, and the most up-to-date criteria for
the correct use of pairing-based cryptography. We thereby deliberately avoid
most of the technical details and rather give special emphasis on the
importance of the correct use of bilinear maps by realizing secure
cryptographic protocols. We list a collection of some recent papers having
wrong security assumptions or realizability/efficiency issues. Finally, we give
a compact and an up-to-date recipe of the correct use of pairings.Comment: 25 page
From service-oriented architecture to service-oriented enterprise
Service-Oriented Architecture (SOA) was originally motivated by enterprise demands for better business-technology alignment and higher flexibility and reuse. SOA evolved from an initial set of ideas and principles to Web services (WS) standards now widely accepted by industry. The next phase of SOA development is concerned with a scalable, reliable and secure infrastructure based on these standards, and guidelines, methods and techniques for developing and maintaining service delivery in dynamic enterprise settings. In this paper we discuss the principles and main elements of SOA. We then present an overview of WS standards. And finally we come back to the original motivation for SOA, and how these can be realized
Composability in quantum cryptography
In this article, we review several aspects of composability in the context of
quantum cryptography. The first part is devoted to key distribution. We discuss
the security criteria that a quantum key distribution protocol must fulfill to
allow its safe use within a larger security application (e.g., for secure
message transmission). To illustrate the practical use of composability, we
show how to generate a continuous key stream by sequentially composing rounds
of a quantum key distribution protocol. In a second part, we take a more
general point of view, which is necessary for the study of cryptographic
situations involving, for example, mutually distrustful parties. We explain the
universal composability framework and state the composition theorem which
guarantees that secure protocols can securely be composed to larger
applicationsComment: 18 pages, 2 figure
How to make unforgeable money in generalised probabilistic theories
We discuss the possibility of creating money that is physically impossible to
counterfeit. Of course, "physically impossible" is dependent on the theory that
is a faithful description of nature. Currently there are several proposals for
quantum money which have their security based on the validity of quantum
mechanics. In this work, we examine Wiesner's money scheme in the framework of
generalised probabilistic theories. This framework is broad enough to allow for
essentially any potential theory of nature, provided that it admits an
operational description. We prove that under a quantifiable version of the
no-cloning theorem, one can create physical money which has an exponentially
small chance of being counterfeited. Our proof relies on cone programming, a
natural generalisation of semidefinite programming. Moreover, we discuss some
of the difficulties that arise when considering non-quantum theories.Comment: 27 pages, many diagrams. Comments welcom
Quantum Cryptography in Practice
BBN, Harvard, and Boston University are building the DARPA Quantum Network,
the world's first network that delivers end-to-end network security via
high-speed Quantum Key Distribution, and testing that Network against
sophisticated eavesdropping attacks. The first network link has been up and
steadily operational in our laboratory since December 2002. It provides a
Virtual Private Network between private enclaves, with user traffic protected
by a weak-coherent implementation of quantum cryptography. This prototype is
suitable for deployment in metro-size areas via standard telecom (dark) fiber.
In this paper, we introduce quantum cryptography, discuss its relation to
modern secure networks, and describe its unusual physical layer, its
specialized quantum cryptographic protocol suite (quite interesting in its own
right), and our extensions to IPsec to integrate it with quantum cryptography.Comment: Preprint of SIGCOMM 2003 pape
On the Efficiency of Classical and Quantum Secure Function Evaluation
We provide bounds on the efficiency of secure one-sided output two-party
computation of arbitrary finite functions from trusted distributed randomness
in the statistical case. From these results we derive bounds on the efficiency
of protocols that use different variants of OT as a black-box. When applied to
implementations of OT, these bounds generalize most known results to the
statistical case. Our results hold in particular for transformations between a
finite number of primitives and for any error. In the second part we study the
efficiency of quantum protocols implementing OT. While most classical lower
bounds for perfectly secure reductions of OT to distributed randomness still
hold in the quantum setting, we present a statistically secure protocol that
violates these bounds by an arbitrarily large factor. We then prove a weaker
lower bound that does hold in the statistical quantum setting and implies that
even quantum protocols cannot extend OT. Finally, we present two lower bounds
for reductions of OT to commitments and a protocol based on string commitments
that is optimal with respect to both of these bounds
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