14 research outputs found

    Efficient and Verifiable Algorithms for Secure Outsourcing of Cryptographic Computations

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    The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.Reducing computational cost of cryptographic computations for resource-constrained devices is an active research area. One of the practical solutions is to securely outsource the computations to an external and more powerful cloud server. Modular exponentiations are the most expensive computation from the cryptographic point of view. Therefore, outsourcing modular exponentiations to a single, external and potentially untrusted cloud server while ensuring the security and privacy provide an efficient solution. In this paper, we propose new efficient outsourcing algorithms for modular exponentiations using only one untrusted cloud server. These algorithms cover public-base & private-exponent, private-base & public-exponent, private-base & privateexponent, and more generally private-base & private-exponents simultaneous modular exponentiations. Our algorithms are the most efficient solutions utilizing only one single untrusted server with best checkability probabilities. Furthermore, unlike existing schemes, which have fixed checkability probability, our algorithms provide adjustable predetermined checkability parameters. Finally, we apply our algorithms to outsource Oblivious Transfer Protocols and Blind Signatures which are expensive primitives in modern cryptography

    Noninteractive Verifiable Outsourcing Algorithm for Bilinear Pairing with Improved Checkability

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    It is well known that the computation of bilinear pairing is the most expensive operation in pairing-based cryptography. In this paper, we propose a noninteractive verifiable outsourcing algorithm of bilinear pairing based on two servers in the one-malicious model. The outsourcer need not execute any expensive operation, such as scalar multiplication and modular exponentiation. Moreover, the outsourcer could detect any failure with a probability close to 1 if one of the servers misbehaves. Therefore, the proposed algorithm improves checkability and decreases communication cost compared with the previous ones. Finally, we utilize the proposed algorithm as a subroutine to achieve an anonymous identity-based encryption (AIBE) scheme with outsourced decryption and an identity-based signature (IBS) scheme with outsourced verification

    New Algorithms for Secure Outsourcing of Modular Exponentiations

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    With the rapid development in availability of cloud services, the techniques for securely outsourcing the prohibitively expensive computations to untrusted servers are getting more and more attentions in the scientific community. Exponentiations modulo a large prime have been considered the most expensive operation in discrete-logarithm based cryptographic protocols, and the computationally limited devices such as RFID tags or smartcard may be incapable to accomplish these operations. Therefore, it is meaningful to present an efficient method to securely outsource most of this work-load to (untrusted) cloud servers. In this paper, we propose a new secure outsourcing algorithm for (variable-exponent, variable-base) exponentiation modular a prime in the two untrusted program model. Compared with the state-of-the-art algorithm \cite{HL05}, the proposed algorithm is superior in both efficiency and checkability. We then utilize this algorithm as a subroutine to achieve outsource-secure Cramer-Shoup encryptions and Schnorr signatures. Besides, we propose the first outsource-secure and efficient algorithm for simultaneous modular exponentiations. Moreover, we formally prove that both the algorithms can achieve the desired security notions. We also provide the experimental evaluation that demonstrates the efficiency and effectiveness of the proposed outsourcing algorithms and schemes

    New Approaches for Secure Outsourcing Algorithm for Modular Exponentiations

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    Outsourcing paradigm is one of the most attractive benefits of cloud computing, where computation workloads can be outsourced to cloud servers by the resource-constrained devices, such as RFID tags. With this paradigm, cloud users can avoid setting up their own infrastructures. As a result, some new challenges, such as security and checkability, are inevitably introduced. In this paper, we address the problem of secure outsourcing algorithm for modular exponentiations in the one-malicious version of two untrusted program model. We show that our proposed algorithm is more efficient than the state-of-the-art algorithms. On the other hand, we point out in this paper that the first outsource-secure algorithm for simultaneous modular exponentiations proposed recently is insecure, where the sensitive information can be leaked to the malicious servers. As a result, we propose a new and more efficient algorithm for simultaneous modular exponentiations. We also propose the constructions for outsource-secure Cramer-Shoup encryptions and Schnorr signatures which are also more efficient than the state-of-the-art algorithms

    A Review on: Association Rule Mining Using Privacy for Partitioned Database

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    Data Analysis techniques that are Association manage mining and Frequent thing set mining are two prominent and broadly utilized for different applications. The conventional framework concentrated independently on vertically parceled database and on a level plane apportioned databases on the premise of this presenting a framework which concentrate on both on a level plane and vertically divided databases cooperatively with protection safeguarding component. Information proprietors need to know the continuous thing sets or affiliation rules from an aggregate information set and unveil or uncover as few data about their crude information as could reasonably be expected to other information proprietors and outsiders. To guarantee information protection a Symmetric Encryption Technique is utilized to show signs of improvement result. Cloud supported successive thing set mining arrangement used to exhibit an affiliation govern mining arrangement. The subsequent arrangements are intended for outsourced databases that permit various information proprietors to proficiently share their information safely without trading off on information protection. Information security is one of the key procedures in outsourcing information to different outside clients. Customarily Fast Distribution Mining calculation was proposed for securing conveyed information. These business locales an issue by secure affiliation governs over parceled information in both even and vertical. A Frequent thing sets calculation and Distributed affiliation administer digging calculation is used for doing above method adequately in divided information, which incorporates administrations of the information in outsourcing process for disseminated databases. This work keeps up or keeps up proficient security over vertical and flat perspective of representation in secure mining applications

    Hide The Modulus: A Secure Non-Interactive Fully Verifiable Delegation Scheme for Modular Exponentiations via CRT

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    Security protocols using public-key cryptography often requires large number of costly modular exponentiations (MEs). With the proliferation of resource-constrained (mobile) devices and advancements in cloud computing, delegation of such expensive computations to powerful server providers has gained lots of attention. In this paper, we address the problem of verifiably secure delegation of MEs using two servers, where at most one of which is assumed to be malicious (the OMTUP-model). We first show verifiability issues of two recent schemes: We show that a scheme from IndoCrypt 2016 does not offer full verifiability, and that a scheme for nn simultaneous MEs from AsiaCCS 2016 is verifiable only with a probability 0.59090.5909 instead of the author\u27s claim with a probability 0.99550.9955 for n=10n=10. Then, we propose the first non-interactive fully verifiable secure delegation scheme by hiding the modulus via Chinese Remainder Theorem (CRT). Our scheme improves also the computational efficiency of the previous schemes considerably. Hence, we provide a lightweight delegation enabling weak clients to securely and verifiably delegate MEs without any expensive local computation (neither online nor offline). The proposed scheme is highly useful for devices having (a) only ultra-lightweight memory, and (b) limited computational power (e.g. sensor nodes, RFID tags)

    New Efficient and Flexible Algorithms for Secure Outsourcing of Bilinear Pairings

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    Outsourcing paradigm has become a hot research topic in the cryptography community, where computation workloads can be outsourced to cloud servers by the resource-constrained devices, such as RFID tags. The computation of bilinear pairings is the most expensive operation in pairing-based cryptographic primitives. In this paper, we present two new algorithms for secure outsourcing the computation of bilinear pairings. One is secure in the OMTUP model. The other, which provides flexible checkability, is in the TUP model. Compared with the state-of-the-art algorithms, our proposal is more efficient

    Fully Verifiable Secure Delegation of Pairing Computation: Cryptanalysis and An Efficient Construction

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    We address the problem of secure and verifiable delegation of general pairing computation. We first analyze some recently proposed pairing delegation schemes and present several attacks on their security and/or verifiability properties. In particular, we show that none of these achieve the claimed security and verifiability properties simultaneously. We then provide a fully verifiable secure delegation scheme VerPair{\sf VerPair} under one-malicious version of a two-untrusted-program model (OMTUP). VerPair{\sf VerPair} not only significantly improves the efficiency of all the previous schemes, such as fully verifiable schemes of Chevallier-Mames et al. and Canard et al. by eliminating the impractical exponentiation- and scalar-multiplication-consuming steps, but also offers for the first time the desired full verifiability property unlike other practical schemes. Furthermore, we give a more efficient and less memory consuming invocation of the subroutine Rand{\sf Rand} for VerPair{\sf VerPair} by eliminating the requirement of offline computations of modular exponentiations and scalar-multiplications. In particular, Rand{\sf Rand} includes a fully verifiable partial delegation under the OMTUP assumption. The partial delegation of Rand{\sf Rand} distinguishes VerPair{\sf VerPair} as a useful lightweight delegation scheme when the delegator is resource-constrained (e.g. RFID tags, smart cards or sensor nodes)

    Secure Delegation of Isogeny Computations and Cryptographic Applications

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    We address the problem of speeding up isogeny computation for supersingular elliptic curves over finite fields using untrusted computational resources like third party servers or cloud service providers (CSPs). We first propose new, efficient and secure delegation schemes. This especially enables resource-constrained devices (e.g. smart cards, RFID tags, tiny sensor nodes) to effectively deploy post-quantum isogeny-based cryptographic protocols. To the best of our knowledge, these new schemes are the first attempt to generalize the classical secure delegation schemes for group exponentiations and pairing computation to an isogeny-based post-quantum setting. Then, we apply these secure delegation subroutines to improve the performance of supersingular isogeny-based zero-knowledge proofs of identity. Our experimental results show that, at the 128−bit quantum-security level, the proving party only needs about 3% of the original protocol cost, while the verifying party’s effort is fully reduced to comparison operations. Lastly, we also apply our delegation schemes to decrease the computational cost of the decryption step for the NIST postquantum standardization candidate SIKE
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