3,162 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
Revisiting the Sanders-Freiman-Ruzsa Theorem in and its Application to Non-malleable Codes
Non-malleable codes (NMCs) protect sensitive data against degrees of
corruption that prohibit error detection, ensuring instead that a corrupted
codeword decodes correctly or to something that bears little relation to the
original message. The split-state model, in which codewords consist of two
blocks, considers adversaries who tamper with either block arbitrarily but
independently of the other. The simplest construction in this model, due to
Aggarwal, Dodis, and Lovett (STOC'14), was shown to give NMCs sending k-bit
messages to -bit codewords. It is conjectured, however, that the
construction allows linear-length codewords. Towards resolving this conjecture,
we show that the construction allows for code-length . This is achieved
by analysing a special case of Sanders's Bogolyubov-Ruzsa theorem for general
Abelian groups. Closely following the excellent exposition of this result for
the group by Lovett, we expose its dependence on for the
group , where is a prime
RC4 Encryption-A Literature Survey
AbstractA chronological survey demonstrating the cryptanalysis of RC4 stream cipher is presented in this paper. We have summarized the various weaknesses of RC4 algorithm followed by the recently proposed enhancements available in the literature. It is established that innovative research efforts are required to develop secure RC4 algorithm, which can remove the weaknesses of RC4, such as biased bytes, key collisions, and key recovery attacks on WPA. These flaws in RC4 are still offering an open challenge for developers. Hence our chronological survey corroborates the fact that even though researchers are working on RC4 stream cipher since last two decades, it still offers a plethora of research issues. The attraction of community towards RC4 is still alive
Indistinguishability Obfuscation from Well-Founded Assumptions
In this work, we show how to construct indistinguishability obfuscation from
subexponential hardness of four well-founded assumptions. We prove:
Let be arbitrary
constants. Assume sub-exponential security of the following assumptions, where
is a security parameter, and the parameters below are
large enough polynomials in :
- The SXDH assumption on asymmetric bilinear groups of a prime order ,
- The LWE assumption over with subexponential
modulus-to-noise ratio , where is the dimension of the LWE
secret,
- The LPN assumption over with polynomially many LPN samples
and error rate , where is the dimension of the LPN
secret,
- The existence of a Boolean PRG in with stretch
,
Then, (subexponentially secure) indistinguishability obfuscation for all
polynomial-size circuits exists
Indistinguishability Obfuscation: From Approximate to Exact
We show general transformations from subexponentially-secure approximate indistinguishability obfuscation (IO) where the obfuscated circuit agrees with the original circuit on a 1/2+ϵ fraction of inputs on a certain samplable distribution, into exact indistinguishability obfuscation where the obfuscated circuit and the original circuit agree on all inputs. As a step towards our results, which is of independent interest, we also obtain an approximate-to-exact transformation for functional encryption. At the core of our techniques is a method for “fooling” the obfuscator into giving us the correct answer, while preserving the indistinguishability-based security. This is achieved based on various types of secure computation protocols that can be obtained from different standard assumptions.
Put together with the recent results of Canetti, Kalai and Paneth (TCC 2015), Pass and Shelat (TCC 2016), and Mahmoody, Mohammed and Nemathaji (TCC 2016), we show how to convert indistinguishability obfuscation schemes in various ideal models into exact obfuscation schemes in the plain model.National Science Foundation (U.S.) (Grant CNS-1350619)National Science Foundation (U.S.) (Grant CNS-1414119
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