Context-aware Verifiable Cloud Computing

Internet of Things (IoTs) has emerged to motivate various intelligent applications based on the data collected by various 'things.' Cloud computing plays an important role for big data processing by providing data computing and processing services. However, cloud service providers may invade data privacy and provide inaccurate data processing results to users, and thus cannot be fully trusted. On the other hand, limited by computation resources and capabilities, cloud users mostly cannot independently process big data and perform verification on the correctness of data processing. This raises a special challenge on cloud computing verification, especially when user data are stored at the cloud in an encrypted form and processed for satisfying the requests raised in different contexts. But the current literature still lacks serious studies on this research issue. In this paper, we propose a context-aware verifiable computing scheme based on full homomorphic encryption by deploying an auditing protocol to verify the correctness of the encrypted data processing result. We design four optional auditing protocols to satisfy different security requirements. Their performance is evaluated and compared through performance analysis, algorithm implementation, and system simulation. The results show the effectiveness and efficiency of our designs. The pros and cons of all protocols are also analyzed and discussed based on rigorous comparison.Peer reviewe

Verifiable outsourced computation over encrypted data

In recent years, cloud computing has become the most popular and promising service platform. A cloud user can outsource its heavy computation overhead to a cloud service provider (CSP) and let the CSP make the computation instead. In order to guarantee the correctness of the outsourced processing (e.g., machine learning and data mining), a proof should be provided by the CSP in order to make sure that the processing is carried out properly. On the other hand, from the security and privacy points of view, users will always encrypt their sensitive data first before they are outsourced to the CSP rather than sending the raw data directly. However, processing and verifying of encrypted data computation has always been a challenging problem. Homomorphic Encryption (HE) has been proposed to tackle this task on computations over encrypted data and ensure the confidentiality of the data. However, original HE cannot provide an efficient approach to verify the correctness of computation over encrypted data that is processed by CSP. In this paper, we propose a verifiable outsourced computation scheme over encrypted data with the help of fully homomorphic encryption and polynomial factorization algorithm. Our scheme protects user data security in outsourced processing and allows public verification on the computation result processed by CSP with zero knowledge. We then prove the security of our scheme and analyze its performance by comparing it with some latest related works. Performances analysis shows that our scheme reduces the overload of both the cloud users and the verifier.Peer reviewe

VeriDedup

Tallennetaan OA-artikkeli, kun julkaistuData deduplication is a technique to eliminate duplicate data in order to save storage space and enlarge upload bandwidth, which has been applied by cloud storage systems. However, a cloud storage provider (CSP) may tamper user data or cheat users to pay unused storage for duplicate data that are only stored once. Although previous solutions adopt message-locked encryption along with Proof of Retrievability (PoR) to check the integrity of deduplicated encrypted data, they ignore proving the correctness of duplication check during data upload and require the same file to be derived into same verification tags, which suffers from brute-force attacks and restricts users from flexibly creating their own individual verification tags. In this paper, we propose a verifiable deduplication scheme called VeriDedup to address the above problems. It can guarantee the correctness of duplication check and support flexible tag generation for integrity check over encrypted data deduplication in an integrative way. Concretely, we propose a novel Tag-flexible Deduplication-supported Integrity Check Protocol (TDICP) based on Private Information Retrieval (PIR) by introducing a novel verification tag called noteset, which allows multiple users holding the same file to generate their individual verification tags and still supports tag deduplication at the CSP. Furthermore, we make the first attempt to guarantee the correctness of data duplication check by introducing a novel User Determined Duplication Check Protocol (UDDCP) based on Private Set Intersection (PSI), which can resist a CSP from providing a fake duplication check result to users. Security analysis shows the correctness and soundness of our scheme. Simulation studies based on real data show the efficacy and efficiency of our proposed scheme and its significant advantages over prior arts.Peer reviewe

Secure Outsourced Top-k Selection Queries against Untrusted Cloud Service Providers

Funding Information: ACKNOWLEDGEMENT The authors would like to thank the anonymous reviewers for their constructive comments and helpful advice. This work was partially supported by National Natural Science Foundation of China under Grant 62072351, Academy of Finland under Grant 308087 and Grant 335262, US National Science Foundation through grants CNS-1933069, CNS-1824355, CNS-1651954 (CAREER), CNS-1718078 and CNS-1933047. Publisher Copyright: © 2021 IEEE.As cloud computing reshapes the global IT industry, an increasing number of business owners have outsourced their datasets to third-party cloud service providers (CSP), which in turn answer data queries from end users on their behalf. A well known security challenge in data outsourcing is that the CSP cannot be fully trusted, which may return inauthentic or unsound query results for various reasons. This paper considers top-k selection queries, an important type of queries widely used in practice. In a top-k selection query, a user specifies a scoring function and asks for the k objects with the highest scores. Despite several recent efforts, existing solutions can only support a limited range of scoring functions with explicit forms known in advance. This paper presents three novel schemes that allow a user to verify the integrity and soundness of any top-k selection query result returned by an untrusted CSP. The first two schemes support monotone scoring functions, and the third scheme supports scoring functions comprised of both monotonically non-decreasing and non-increasing subscoring functions. Detailed simulation studies using a real dataset confirm the efficacy and efficiency of the proposed schemes and their significant advantages over prior solutions.Peer reviewe

Degradation kinetics of calcium polyphosphate bioceramic: an experimental and theoretical study

In this work, the degradation kinetics of calcium polyphosphate bioceramic was studied. Liquid state31P nuclear magnetic resonance (NMR), X-ray diffraction (XRD) and scanning electron microscope (SEM) were used to characterize the product. The in vitro degradation test was carried out at 37 ºC for up to 48 hours for both the simulation solution and the extreme solution. The ion concentrations were measured and analyzed by establishing a mathematical model referring to the chemical reaction kinetics. The results indicated that the degradability of calcium polyphosphate increased with the decrease of pH value, and the sample showed a rapid loss of ion concentration within the initial period of immersion followed by a slower loss ratio. The relationship between ion concentration and the degradation time coincided with Boxlucas model

Cascade Regulation of the Proliferation, Recruitment, and Differentiation of Stem Cells to Prevent Aseptic Loosening by GNPs/ECPP Particles Responding to Macrophages: <i>In Vitro</i> and <i>In Vivo</i>

Modulating both inflammation and stem cells by designing an artificial joint material to obtain the continuous prevention and control on aseptic loosening (AL) is a novel strategy. In this paper, graphene/europium-doped calcium polyphosphate (GNPs/ECPP) particles were obtained by ultrasound method and spark plasma sintering (SPS) method. The prepared particles were used to modulate the inflammatory response and further obtain cascade regulation on the proliferation, recruitment, and differentiation of stem cells. The results showed that particles obtained by SPS had a stronger effect on promoting the proliferation and differentiation of stem cells, while by ultrasound method more stem cells were recruited. Besides, the graphene and Eu3+ contained in the particles obtained by SPS method could effectively play a synergistic role on the differentiation of stem cells. In vivo experiment results demonstrated that the composite particles effectively suppress the inflammatory response, recruit stem cells, and prevent AL by inhibiting the secretion of inflammatory factors