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111
Compact Proofs of Retrievability
, 2008
"... In a proofofretrievability system, a data storage center must prove to a verifier that he is actually storing all of a client’s data. The central challenge is to build systems that are both efficient and provably secure — that is, it should be possible to extract the client’s data from any prover ..."
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Cited by 195 (0 self)
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In a proofofretrievability system, a data storage center must prove to a verifier that he is actually storing all of a client’s data. The central challenge is to build systems that are both efficient and provably secure — that is, it should be possible to extract the client’s data from any prover that passes a verification check. All previous provably secure solutions require that a prover send O(l) authenticator values (i.e., MACs or signatures) to verify a file, for a total of O(l 2) bits of communication, where l is the security parameter. The extra cost over the ideal O(l) communication can be prohibitive in systems where a verifier needs to check many files. We create the first compact and provably secure proof of retrievability systems. Our solutions allow for compact proofs with just one authenticator value — in practice this can lead to proofs with as little as 40 bytes of communication. We present two solutions with similar structure. The first one is privately verifiable and builds elegantly on pseudorandom functions (PRFs); the second allows for publicly verifiable proofs and is built from the signature scheme of Boneh, Lynn, and Shacham in bilinear groups. Both solutions rely on homomorphic properties to aggregate a proof into one small authenticator value. 1
Signing a Linear Subspace: Signature Schemes for Network Coding
"... Abstract. Network coding offers increased throughput and improved robustness to random faults in completely decentralized networks. In contrast to traditional routing schemes, however, network coding requires intermediate nodes to modify data packets en route; for this reason, standard signature sch ..."
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Cited by 72 (8 self)
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Abstract. Network coding offers increased throughput and improved robustness to random faults in completely decentralized networks. In contrast to traditional routing schemes, however, network coding requires intermediate nodes to modify data packets en route; for this reason, standard signature schemes are inapplicable and it is a challenge to provide resilience to tampering by malicious nodes. Here, we propose two signature schemes that can be used in conjunction with network coding to prevent malicious modification of data. In particular, our schemes can be viewed as signing linear subspaces in the sense that a signature σ on V authenticates exactly those vectors in V. Our first scheme is homomorphic and has better performance, with both public key size and perpacket overhead being constant. Our second scheme does not rely on random oracles and uses weaker assumptions. We also prove a lower bound on the length of signatures for linear subspaces showing that both of our schemes are essentially optimal in this regard. 1
Converting PairingBased Cryptosystems from CompositeOrder Groups to PrimeOrder Groups
"... Abstract. We develop an abstract framework that encompasses the key properties of bilinear groups of composite order that are required to construct secure pairingbased cryptosystems, and we show how to use primeorder elliptic curve groups to construct bilinear groups with the same properties. In p ..."
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Cited by 56 (0 self)
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Abstract. We develop an abstract framework that encompasses the key properties of bilinear groups of composite order that are required to construct secure pairingbased cryptosystems, and we show how to use primeorder elliptic curve groups to construct bilinear groups with the same properties. In particular, we define a generalized version of the subgroup decision problem and give explicit constructions of bilinear groups in which the generalized subgroup decision assumption follows from the decision DiffieHellman assumption, the decision linear assumption, and/or related assumptions in primeorder groups. We apply our framework and our primeorder group constructions to create more efficient versions of cryptosystems that originally required compositeorder groups. Specifically, we consider the BonehGohNissim encryption scheme, the BonehSahaiWaters traitor tracing system, and the KatzSahaiWaters attributebased encryption scheme. We give a security theorem for the primeorder group instantiation of each system, using assumptions of comparable complexity to those used in the compositeorder setting. Our conversion of the last two systems to primeorder groups answers a problem posed by Groth and Sahai.
Efficient and generalized pairing computation on Abelian varieties
, 2008
"... In this paper, we propose a new method for constructing a bilinear pairing over (hyper)elliptic curves, which we call the Rate pairing. This pairing is a generalization of the Ate and Atei pairing, and also improves efficiency of the pairing computation. Using the Rate pairing, the loop length in ..."
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Cited by 55 (3 self)
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In this paper, we propose a new method for constructing a bilinear pairing over (hyper)elliptic curves, which we call the Rate pairing. This pairing is a generalization of the Ate and Atei pairing, and also improves efficiency of the pairing computation. Using the Rate pairing, the loop length in Miller’s algorithm can be as small as log(r 1/φ(k) ) for some pairingfriendly elliptic curves which have not reached this lower bound. Therefore we obtain from 29 % to 69 % savings in overall costs compared to the Atei pairing. On supersingular hyperelliptic curves of genus 2, we show that this approach makes the loop length in Miller’s algorithm shorter than that of the Ate pairing.
Optimal Pairings
"... Abstract. In this paper we introduce the concept of an optimal pairing, which by definition can be computed using only log 2 r/ϕ(k) basic Miller iterations, with r the order of the groups involved and k the embedding degree. We describe an algorithm to construct optimal ate pairings on all parametri ..."
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Abstract. In this paper we introduce the concept of an optimal pairing, which by definition can be computed using only log 2 r/ϕ(k) basic Miller iterations, with r the order of the groups involved and k the embedding degree. We describe an algorithm to construct optimal ate pairings on all parametrized families of pairing friendly elliptic curves. Finally, we conjecture that any nondegenerate pairing on an elliptic curve without efficiently computable endomorphisms different from powers of Frobenius requires at least log 2 r/ϕ(k) basic Miller iterations.
Faster explicit formulas for computing pairings over ordinary curves
, 2010
"... We describe e cient formulas for computing pairings on ordinary elliptic curves over prime fields. First, we generalize lazy reduction techniques, previously considered only for arithmetic in quadratic extensions, to the whole pairing computation, including towering and curve arithmetic. Second, we ..."
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Cited by 38 (8 self)
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We describe e cient formulas for computing pairings on ordinary elliptic curves over prime fields. First, we generalize lazy reduction techniques, previously considered only for arithmetic in quadratic extensions, to the whole pairing computation, including towering and curve arithmetic. Second, we introduce a new compressed squaring formula for cyclotomic subgroups and a new technique to avoid performing an inversion in the final exponentiation when the curve is parameterized by a negative integer. The techniques are illustrated in the context of pairing computation over BarretoNaehrig curves, where they have a particularly efficient realization, and also combined with other important developments in the recent literature. The resulting formulas reduce the number of required operations and, consequently, execution time, improving on the stateoftheart performance of cryptographic pairings by 27%33% on several popular 64bit computing platforms. In particular, our techniques allow to compute a pairing under 2 million cycles for the first time on such architectures.
Implementing cryptographic pairings over BarretoNaehrig curves
 PairingBased Cryptography  Pairing 2007, First International Conference, volume 4575 of Lecture
"... Abstract. In this paper we describe an efficient implementation of the Tate and Ate pairings using BarretoNaehrig pairingfriendly curves, on both a standard 32bit PC and on a 32bit smartcard. First we introduce a subfamily of such curves with a particularly simple representation. Next we consid ..."
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Cited by 33 (2 self)
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Abstract. In this paper we describe an efficient implementation of the Tate and Ate pairings using BarretoNaehrig pairingfriendly curves, on both a standard 32bit PC and on a 32bit smartcard. First we introduce a subfamily of such curves with a particularly simple representation. Next we consider the issues that arise in the efficient implementation of field arithmetic in F p 12, which is crucial to good performance. Various optimisations are suggested, including a novel approach to the ‘final exponentiation’, which is faster and requires less memory than the methods previously recommended. 1
SNARKs for C: Verifying program executions succinctly and in zero knowledge
 In Proceedings of CRYPTO 2013, LNCS
"... An argument system for NP is a proof system that allows efficient verification of NP statements, given proofs produced by an untrusted yet computationallybounded prover. Such a system is noninteractive and publiclyverifiable if, after a trusted party publishes a proving key and a verification key, ..."
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Cited by 28 (1 self)
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An argument system for NP is a proof system that allows efficient verification of NP statements, given proofs produced by an untrusted yet computationallybounded prover. Such a system is noninteractive and publiclyverifiable if, after a trusted party publishes a proving key and a verification key, anyone can use the proving key to generate noninteractive proofs for adaptivelychosen NP statements, and proofs can be verified by anyone by using the verification key. We present an implementation of a publiclyverifiable noninteractive argument system for NP. The system, moreover, is a zeroknowledge proofofknowledge. It directly proves correct executions of programs on TinyRAM, a randomaccess machine tailored for efficient verification of nondeterministic computations. Given a program P and time bound T, the system allows for proving correct execution of P, on any input x, for up to T steps, after a onetime setup requiring Õ(P  · T) cryptographic operations. An honest prover requires Õ(P  · T) cryptographic operations to generate such a proof, while proof verification can be performed with only O(x) cryptographic operations. This system can be used to prove the correct execution of C programs, using our TinyRAM port of the GCC compiler. This yields a zeroknowledge Succinct Noninteractive ARgument of Knowledge (zkSNARK) for
An introduction to pairingbased cryptography
, 2005
"... Bilinear pairings have been used to design ingenious protocols for such tasks as oneround threeparty key agreement, identitybased encryption, and aggregate signatures. Suitable bilinear pairings can be constructed from ..."
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Cited by 26 (0 self)
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Bilinear pairings have been used to design ingenious protocols for such tasks as oneround threeparty key agreement, identitybased encryption, and aggregate signatures. Suitable bilinear pairings can be constructed from
Highspeed software implementation of the optimal ate pairing over Barreto–Naehrig curves
 PAIRINGBASED CRYPTOGRAPHY–PAIRING 2010. LECTURE NOTES IN COMPUTER SCIENCE
, 2010
"... This paper describes the design of a fast software library for the computation of the optimal ate pairing on a Barreto–Naehrig elliptic curve. Our library is able to compute the optimal ate pairing over a 254bit prime field Fp, injust2.33 million of clock cycles on a single core of an Intel Core ..."
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Cited by 25 (3 self)
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This paper describes the design of a fast software library for the computation of the optimal ate pairing on a Barreto–Naehrig elliptic curve. Our library is able to compute the optimal ate pairing over a 254bit prime field Fp, injust2.33 million of clock cycles on a single core of an Intel Core i7 2.8GHz processor, which implies that the pairing computation takes 0.832msec. We are able to achieve this performance by a careful implementation of the base field arithmetic through the usage of the customary Montgomery multiplier for prime fields. The prime field is constructed via the Barreto–Naehrig polynomial parametrization of the prime p given as, p =36t 4 +36t 3 +24t 2 +6t +1, with t =2 62 − 2 54 +2 44. This selection of t allows us to obtain important savings for both the Miller loop as well as the final exponentiation steps of the optimal ate pairing.