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With the rapid development of bioinformatics and the availability of genetic sequencing technologies, genomic data has been used to facilitate personalized medicine. Cloud computing, features as low cost, rich storage and rapid processing can precisely respond to the challenges brought by the emergence of massive genomic data. Considering the security of cloud platform and the privacy of genomic data, we first introduce P2GT which utilizes key-policy attribute-based encryption to realize genomic data access control with unbounded attributes, and employs equality test algorithm to achieve personalized medicine test by matching digitized single nucleotide polymorphisms (SNPs) directly on the users’ ciphertext without encrypting multiple times. We then propose an enhanced scheme P2GT+, which adopts identity-based encryption with equality test supporting flexible joint authorization to realize privacy-preserving paternity test, genetic compatibility test and disease susceptibility test over the encrypted SNPs with P2GT. We prove the security of proposed schemes and conduct extensive experiments with the 1,000 Genomes dataset. The results show that P2GT and P2GT+ are practical and scalable enough to meet the privacy-preserving and authorized genetic testing requirements in cloud computing. [ABSTRACT FROM AUTHOR]

In Location-Based Social Networks (LBSNs), registered users submit their reviews for visited point-of-interests (POIs) to the system providers (SPs). The SPs anonymously publish submitted reviews to build reputations for POIs. Unfortunately, the user profile and trajectory contained in reviews can be easily obtained by adversaries who SPs has compromised with. Even worse, existing techniques, such as cryptography and generalization, etc., are infeasible due to the necessity of public publication of reviews and the facticity of reviews. Inspired by pseudonym techniques, we propose an approach to exchanging reviews before users submit reviews to SPs. In our approach, we introduce two attacks, namely review-based location correlation attack (RLCA) and semantic-based long-term statistical attack (SLSA). RLCA can be exploited to link the real user by reconstructing the trajectory, and SLSA can be launched to establish a connection between locations and users through the difference of semantic frequency. To resist RLCA, we design a method named User Selection to Resist RLCA (USR-RLCA) to exchange reviews. We propose a metric to measure the correlation between a user and a trajectory. Based on the metric, USR-RLCA can select reviews resisting RLCA to exchange by suppressing the number of locations on each reconstructed trajectory below the correlation. However, USR-RLCA fails to resist SLSA because of ignoring the essential semantics. Hence, we design an enhanced USR-RLCA named User Selection to Resist SLSA (USR-SLSA). We first propose a metric to measure the indistinguishability of locations concerning the difference of semantic frequency in a long term. Then, USR-SLSA can select reviews resisting SLSA to exchange by allowing two reviews whose indistinguishability is below the probability difference after the exchange to be exchanged. Evaluation results verify the effectiveness of our approach in terms of privacy and utility. [ABSTRACT FROM AUTHOR]

Privacy-preserving multidimensional data aggregation is a significant basic building block for protecting the users’ privacy in smart grid, and it can not only expand the applications of data aggregation but also fulfill the demands of the fine-grained analysis of multidimensional data. However, traditional multidimensional data aggregation schemes depend on the trusted authority and cannot resist the coalition attack from the gateway (GW) and the control center (CC), which may cause the users’ fears about privacy violations. Therefore, this article proposes a privacy-preserving multidimensional data aggregation scheme without trusted authority in smart grid based on the ElGamal homomorphic cryptosystem with distributed decryption, which can resist the coalition attack from the GW and the CC. What is more, the proposed scheme does not depend on the trusted authority which is not fully trusted in the real world. The detailed security analysis indicates that our scheme can satisfy the security requirement of smart grid. The performance analysis shows that the proposed scheme achieves the lowest computation and communication costs in data encryption phase and data aggregation phase, thus it is appropriate for many practical applications. [ABSTRACT FROM AUTHOR]

The Internet of Things (IoT) has attracted extensive attention in the information field. Its rapid development has promoted several monitoring application domains. However, the resource constraint of sensor nodes and the security of data transmission have emerged as significant issues. In this paper, an image communication system for IoT monitoring applications is exploited to solve the above-mentioned problems simultaneously. The proposed system can satisfy the requirements of sensor nodes for low computational complexity, low-energy consumption, and low storage overhead. We also present a new compressed sensing (CS) model, as well as the corresponding parallel reconstruction algorithm, which help to reduce the image encryption/decryption time. Based on chaotic systems, we integrate the quantization and diffusion operations into the system to further enhance the transmission security. The simulations are executed to demonstrate the feasibility and the effectiveness of the proposed method. Compared with the traditional CS, our numerical results indicate that the proposed model reduces $\text{413}\,{\text{ms}}$ computation time and $\text{3.13} \times {\text{10}^\text{6}}$ elements stored for large-scale images. Besides, we verify the flexibility and the diversity of choosing two submatrices for different-sized images. Experimental results also show the proposed system performs well in terms of security performance. Particularly the key space reaches ${2^{253}}$. [ABSTRACT FROM AUTHOR]

With the emergence and widespread application of cloud computing, the use of cloud platforms to solve the problem of secure multi-party computation has emerged as a new research direction. The traditional computation of a solid geometry is performed through mutual interactions between two parties, which is not suitable in an untrusted cloud computing environment. In this paper, we first design a basic protocol for a secure Euclidean distance calculation that is suitable for cloud platforms and can serve as a building block for other protocols on cloud platforms. Using the solution of the Euclidean distance problem as such a building block, we provide a new method that converts the problems of calculating solid triangular areas and solid tetrahedral volumes into the calculation of distances and determinants in three-dimensional space. Then, we discuss solid point-line distance calculations, which extent the idea of the spatial geometry security problem. We present protocols for the above problems and prove that the proposed protocols can resist conspiracy among users and the untrusted cloud platform so that they can effectively ensure the privacy of the users. We also analyze the performances of these solutions. The analysis results show that our scheme is more versatile. [ABSTRACT FROM AUTHOR]

Data collaboration in cloud computing is more and more popular nowadays, and proxy deployment schemes are employed to realize cross-cloud data collaboration. However, data security and privacy are the most serious issues that would raise great concerns from users when they adopt cloud systems to handle data collaboration. Different cryptographic techniques are deployed in different cloud service providers, which makes cross-cloud data collaboration to be a deeper challenge. In this paper, we propose an adaptive secure cross-cloud data collaboration scheme with identity-based cryptography (IBC) and proxy re-encryption (PRE) techniques. We first present a secure cross-cloud data collaboration framework, which protects data confidentiality with IBC technique and transfers the collaborated data in an encrypted form by deploying a proxy close to the clouds. We then provide an adaptive conditional PRE protocol with the designed full identity-based broadcast conditional PRE algorithm, which can achieve flexible and conditional data re-encryption among ciphertexts encrypted in identity-based encryption manner and ciphertexts encrypted in identity-based broadcast encryption manner. The extensive analysis and experimental evaluations demonstrate the well security and performance of our scheme, which meets the secure data collaboration requirements in cross-cloud scenarios. [ABSTRACT FROM AUTHOR]

In a general (k, n) scalable secret image sharing (SSIS) scheme, the secret image is shared by n participants and any k or more than k participants have the ability to reconstruct it. The scalability means that the amount of information in the reconstructed image scales in proportion to the number of the participants. In most existing SSIS schemes, the size of each image shadow is relatively large and the dealer does not has a flexible control strategy to adjust it to meet the demand of differen applications. Besides, almost all existing SSIS schemes are not applicable under noise circumstances. To address these deficiencies, in this paper we present a novel SSIS scheme based on a brand-new technique, called compressed sensing, which has been widely used in many fields such as image processing, wireless communication and medical imaging. Our scheme has the property of flexibility, which means that the dealer can achieve a compromise between the size of each shadow and the quality of the reconstructed image. In addition, our scheme has many other advantages, including smooth scalability, noise-resilient capability, and high security. The experimental results and the comparison with similar works demonstrate the feasibility and superiority of our scheme. [ABSTRACT FROM AUTHOR]

A digital signature scheme allows a signer to sign electronic messages using his or her secret key, and any verifier can validate the correctness according to a given verification procedure. Although a variety of lattice-based signature schemes have been proposed in the past few years, there does not exist a scheme that has short signatures and constant-size public keys simultaneously. In this paper, we propose a new method for constructing short lattice signatures with constant-size public keys in the standard model. In our scheme, each signature contains a low-dimensional lattice vector and the public key only contains three matrices plus a vector. Compared with previous constructions, our scheme is very simple and does not require any complex homomorphic computation. In order for security proof to work, we introduce a new hard lattice problem, called variant small integer solution (Variant-SIS), and give the security reduction from small integer solution to Variant-SIS. Then we define a family of hash functions based on the hardness of Variant-SIS and prove its security properties, including one-wayness and collision resistance. As a matter of independent interest, the proposed hard problem may be useful in many other lattice-based cryptographic constructions. Last, the comparison with similar works demonstrates the superiority of our scheme. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

User anonymity is one of the key security features of an authenticated key agreement especially for communicating messages via an insecure network. Owing to the better properties and higher performance of chaotic theory, the chaotic maps have been introduced into the security schemes, and hence numerous key agreement schemes have been put forward under chaotic-maps. Recently, Xie et al. released an enhanced scheme under Farash et al.’s scheme and claimed their improvements could withstand the security loopholes pointed out in the scheme of Farash et al., i.e., resistance to the off-line password guessing and user impersonation attacks. Nevertheless, through our careful analysis, the improvements were released by Xie et al. still could not solve the problems troubled in Farash et al‥ Besides, Xie et al.’s improvements failed to achieve the user anonymity and the session key security. With the purpose of eliminating the security risks of the scheme of Xie et al., we design an anonymous password-based three-party authenticated key agreement under chaotic maps. Both the formal analysis and the formal security verification using AVISPA are presented. Also, BAN logic is used to show the correctness of the enhancements. Furthermore, we also demonstrate that the design thwarts most of the common attacks. We also make a comparison between the recent chaotic-maps based schemes and our enhancements in terms of performance. [ABSTRACT FROM AUTHOR]

SUMMARY Most robust and noninteractive threshold public key encryption (PKE) schemes have only been proven secure against chosen-ciphertext attacks under the static corruption model; yet, the dynamic corruption model is more reasonable. In this paper, on the basis of bilinear groups of prime order and dual pairing vector spaces, we propose a threshold PKE scheme that is noninteractive, robust and, secure against adaptive chosen-ciphertext attacks under the dynamic corruption model without random oracles. Moreover, our scheme is shown to be more efficient than currently existing fully secure threshold PKE schemes. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Recently, Lee et al. used their new group signature with the function of authenticated encryption to design a sealed-bid auction scheme, and they claimed that their schemes are secure. In this paper, we show that if the group manager has a valid group signature of a member, without the member's secret key, he can forge a group signature on arbitrary message on behalf of the member; then, if the registration manager (RM) and the auction manager (AM) conspired (with each other) in their auction scheme, they can forge a new bid on any goods on behalf of the bidder who has sent his/her bid to AM. Therefore, their group signature and auction scheme are insecure. Finally, we improve Lee et al.'s group signature scheme to overcome the modification attack and achieve the security requirements. [ABSTRACT FROM AUTHOR]

In the literature He et al. (Quantum Inf Process, ) performed the cryptanalysis about the protocol of secure quantum auction with post-confirmation, and proposed the melioration algorithm in order to defeat the collusion among some malicious bidders in Zhao et al.'s protocol (Zhao et al. in Opt Commun 283:3194, ). But unfortunately, this protocol can't defeat the collusion among some malicious bidders either. In this paper, we will analyze the security of He et al.'s protocol and point out the potential loophole. Furthermore, we propose an improved protocol which can defeat the collusion among malicious bidders effectively. [ABSTRACT FROM AUTHOR]

ABSTRACT We propose a new public-key cryptosystem named conjugacy search problem-based Diffie-Hellman integrated encryption scheme (CSP-DHIES), by using conjugation-related assumptions for a special monoid of matrices of truncated multi-variable polynomials over the ring ℤ12 where the CSP is assumed to be intractable. Our construction can be viewed as the first noncommunicative variant of the well-known DHIES cryptosystem. Under the assumptions of the intractability of the CSP-based hash Diffie-Hellman problem and the CSP-based oracle Diffie-Hellman problem, our scheme is provably secure against both chosen-plaintext attacks and secure against chosen-ciphertext attacks. Our proofs are constructed in the standard model. We also discuss the possibility of implementing our proposal using braid groups. Copyright © 2011 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Summary: In a short signature scheme, the length of signature is much smaller than that of the general signature. Short signatures are widely used in low‐computation, low‐storage, and low‐bandwidth communication environments. The proof of security of all certificateless short signature schemes currently known is given in the random oracle model. In this paper, a new certificateless short signature scheme is constructed, and it is proved to be unforgeable in the standard model. Taken into account the computation costs, the scheme performs only one pairing operation, so it is more efficient than previous ones. In this paper, we propose a new certificateless short signature scheme with the following features: It is the first provably secure CLSS scheme in the standard model.It is secure against strong Type I/II adversary. Namely, if the Type I/II adversary replaced the public key of a user, then he may get the valid signatures from the user after he submits the new secret value.It needs only one pairing operation, so it is more efficient than previous ones. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents an improved impossible differential cryptanalysis of SAFER ciphers, which uses the miss-in-the-middle technique developed by Biham et al. We analyze 3.75-round SAFER SK-64, [1] (In this paper, the number in the name of the ciphers indicates the key length). 1 using chosen plaintexts, bytes memory and half round computations. Furthermore, the new impossible differential attack on 3.75-round SAFER+/128 uses chosen plaintexts, half round computations and bytes memory. And attack on 3.75-round SAFER++/128 uses data, time, and memory. [Copyright &y& Elsevier]