1,874 research outputs found

    Still Wrong Use of Pairings in Cryptography

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    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

    RC4 Encryption-A Literature Survey

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    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

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    In this work, we show how to construct indistinguishability obfuscation from subexponential hardness of four well-founded assumptions. We prove: Let τ∈(0,∞),Ύ∈(0,1),ϔ∈(0,1)\tau \in (0,\infty), \delta \in (0,1), \epsilon \in (0,1) be arbitrary constants. Assume sub-exponential security of the following assumptions, where λ\lambda is a security parameter, and the parameters ℓ,k,n\ell,k,n below are large enough polynomials in λ\lambda: - The SXDH assumption on asymmetric bilinear groups of a prime order p=O(2λ)p = O(2^\lambda), - The LWE assumption over Zp\mathbb{Z}_{p} with subexponential modulus-to-noise ratio 2kÏ”2^{k^\epsilon}, where kk is the dimension of the LWE secret, - The LPN assumption over Zp\mathbb{Z}_p with polynomially many LPN samples and error rate 1/ℓή1/\ell^\delta, where ℓ\ell is the dimension of the LPN secret, - The existence of a Boolean PRG in NC0\mathsf{NC}^0 with stretch n1+τn^{1+\tau}, Then, (subexponentially secure) indistinguishability obfuscation for all polynomial-size circuits exists

    Cryptography from tensor problems

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    We describe a new proposal for a trap-door one-way function. The new proposal belongs to the "multivariate quadratic" family but the trap-door is different from existing methods, and is simpler

    CRYSTALS - Kyber: A CCA-secure Module-Lattice-Based KEM

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    Rapid advances in quantum computing, together with the announcement by the National Institute of Standards and Technology (NIST) to define new standards for digital-signature, encryption, and key-establishment protocols, have created significant interest in post-quantum cryptographic schemes. This paper introduces Kyber (part of CRYSTALS - Cryptographic Suite for Algebraic Lattices - a package submitted to NIST post-quantum standardization effort in November 2017), a portfolio of post-quantum cryptographic primitives built around a key-encapsulation mechanism (KEM), based on hardness assumptions over module lattices. Our KEM is most naturally seen as a successor to the NEWHOPE KEM (Usenix 2016). In particular, the key and ciphertext sizes of our new construction are about half the size, the KEM offers CCA instead of only passive security, the security is based on a more general (and flexible) lattice problem, and our optimized implementation results in essentially the same running time as the aforementioned scheme. We first introduce a CPA-secure public-key encryption scheme, apply a variant of the Fujisaki-Okamoto transform to create a CCA-secure KEM, and eventually construct, in a black-box manner, CCA-secure encryption, key exchange, and authenticated-key-exchange schemes. The security of our primitives is based on the hardness of Module-LWE in the classical and quantum random oracle models, and our concrete parameters conservatively target more than 128 bits of post-quantum security

    Indistinguishability Obfuscation: From Approximate to Exact

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    We show general transformations from subexponentially-secure approximate indistinguishability obfuscation (IO) where the obfuscated circuit agrees with the original circuit on a 1/2+Ï” 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

    CRYSTALS - Kyber: A CCA-secure Module-Lattice-Based KEM

    Get PDF
    Rapid advances in quantum computing, together with the announcement by the National Institute of Standards and Technology (NIST) to define new standards for digitalsignature, encryption, and key-establishment protocols, have created significant interest in post-quantum cryptographic schemes. This paper introduces Kyber (part of CRYSTALS - Cryptographic Suite for Algebraic Lattices - a package submitted to NIST post-quantum standardization effort in November 2017), a portfolio of post-quantum cryptographic primitives built around a key-encapsulation mechanism (KEM), based on hardness assumptions over module lattices. Our KEM is most naturally seen as a successor to the NEWHOPE KEM (Usenix 2016). In particular, the key and ciphertext sizes of our new construction are about half the size, the KEM offers CCA instead of only passive security, the security is based on a more general (and flexible) lattice problem, and our optimized implementation results in essentially the same running time as the aforementioned scheme. We first introduce a CPA-secure public-key encryption scheme, apply a variant of the Fujisaki-Okamoto transform to create a CCA-secure KEM, and eventually construct, in a black-box manner, CCA-secure encryption, key exchange, and authenticated-key-exchange schemes. The security of our primitives is based on the hardness of Module-LWE in the classical and quantum random oracle models, and our concrete parameters conservatively target more than 128 bits of postquantum security
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