Background/Objectives: With the rapid development of Internet technology, more and more Internet users tend to store their data and information in the cloud, and the security of the existing cloud storage system has been criticized by people, which is not conducive to protecting the data and information security of users. Therefore, how to effectively guarantee the security of cloud user data becomes more and more important. Security cloud storage system is the key to solve this problem. Methods/Statistical analysis: A secure cloud storage system is implemented for the user’s cloud data security. Its main function is: in the user login phase, the strict user identity authentication method is adopted to control the user’s access rights and prevent illegal users from logging in. Firstly, the identify authentication scheme based on zero knowledge proof is proposed. Secondly, in the user data upload stage, the user data is split. Finally, the encryption algorithm based on elliptic curve is proposed to encrypt the user’s file splitting table. Findings: The experimental results show that, in the user identify authentication stage, compared with the traditional user authentication method, the security of user identify authentication can be greatly improved by using the identify authentication method based on zero-knowledge proof. Improvements/Applications: The secure cloud storage system based on ellipse encryption developed in this thesis can realize the security of user's data by encryption while considering the efficiency of data upload and download, and has a broad application prospect.
Abstract For the current medical block chain, the access rights of electronic medical records and agent encryption are mainly controlled by permission contract. The way of protecting electronic medical records realizes the sharing of medical data, but neglects the management and protection of user identity. In this paper, this article studies the privacy protection technology of the blockchain, combined with the stealth address and zero-knowledge proof technology, and proposes a plan to weigh anonymity and security to protect the privacy of users in the medical blockchain.
The development of information technology has brought great convenience to our lives, but at the same time, the unfairness and privacy issues brought about by traditional centralized systems cannot be ignored. Blockchain is a peer-to-peer and decentralized ledger technology that has the characteristics of transparency, consistency, traceability and fairness, but it reveals private information in some scenarios. Secure multi-party computation (MPC) guarantees enhanced privacy and correctness, so many researchers have been trying to combine secure MPC with blockchain to deal with privacy and trust issues. In this paper, we used homomorphic encryption, secret sharing and zero-knowledge proofs to construct a publicly verifiable secure MPC protocol consisting of two parts-an on-chain computation phase and an off-chain preprocessing phase-and we integrated the protocol as part of the chaincode in Hyperledger Fabric to protect the privacy of transaction data. Experiments showed that our solution performed well on a permissioned blockchain. Most of the time taken to complete the protocol was spent on communication, so the performance has a great deal of room to grow.
We propose three constructions of classically verifiable non-interactive proofs (CV-NIP) and non-interactive zero-knowledge proofs and arguments (CV-NIZK) for QMA in various preprocessing models.
- We construct an information theoretically sound CV-NIP for QMA in the secret parameter model where a trusted party generates a quantum proving key and classical verification key and gives them to the corresponding parties while keeping it secret from the other party. Alternatively, we can think of the protocol as one in a model where the verifier sends an instance-independent quantum message to the prover as preprocessing.
- We construct a CV-NIZK for QMA in the secret parameter model. It is information theoretically sound and zero-knowledge.
- Assuming the quantum hardness of the leaning with errors problem, we construct a CV-NIZK for QMA in a model where a trusted party generates a CRS and the verifier sends an instance-independent quantum message to the prover as preprocessing. This model is the same as one considered in the recent work by Coladangelo, Vidick, and Zhang (CRYPTO '20). Our construction has the so-called dual-mode property, which means that there are two computationally indistinguishable modes of generating CRS, and we have information theoretical soundness in one mode and information theoretical zero-knowledge property in the other. This answers an open problem left by Coladangelo et al, which is to achieve either of soundness or zero-knowledge information theoretically. To the best of our knowledge, ours is the first dual-mode NIZK for QMA in any kind of model.
We propose three constructions of classically verifiable non-interactive zero-knowledge proofs and arguments (CV-NIZK) for QMA in various preprocessing models. - We construct a CV-NIZK for QMA in the quantum secret parameter model where a trusted setup sends a quantum proving key to the prover and a classical verification key to the verifier. It is information theoretically sound and zero-knowledge. - Assuming the quantum hardness of the learning with errors problem, we construct a CV-NIZK for QMA in a model where a trusted party generates a CRS and the verifier sends an instance-independent quantum message to the prover as preprocessing. This model is the same as one considered in the recent work by Coladangelo, Vidick, and Zhang (CRYPTO '20). Our construction has the so-called dual-mode property, which means that there are two computationally indistinguishable modes of generating CRS, and we have information theoretical soundness in one mode and information theoretical zero-knowledge property in the other. This answers an open problem left by Coladangelo et al, which is to achieve either of soundness or zero-knowledge information theoretically. To the best of our knowledge, ours is the first dual-mode NIZK for QMA in any kind of model. - We construct a CV-NIZK for QMA with quantum preprocessing in the quantum random oracle model. This quantum preprocessing is the one where the verifier sends a random Pauli-basis states to the prover. Our construction uses the Fiat-Shamir transformation. The quantum preprocessing can be replaced with the setup that distributes Bell pairs among the prover and the verifier, and therefore we solve the open problem by Broadbent and Grilo (FOCS '20) about the possibility of NIZK for QMA in the shared Bell pair model via the Fiat-Shamir transformation.
Homomorphic Encryption and Zero Knowledge Proofs are two trending concepts that are widely popular as data privacy preservation techniques in a wide variety of applications, especially in those associated with the newly evolved block chain technology which are immutable, distributed and secure. Zero knowledge proof is a cryptographic technique can provide proof that a certain statement is correct, without revealing any details about the statement, while homomorphic encryption allows to perform computations on encrypted data without decrypting it. This article explores the significance of the data privacy aspect provided by both ZKP and Homomorphic Encryption and how it can be effectively used to improvise the privacy of blockchain applications in various domains.\n\n
Motivated by recent Denial of Service (DoS) attacks at the control center and multiple remote power generation sites of a registered entity in the U.S. power grid, we seek to address the lack of sufficient real-time mutual authentication and secure communication between smart grid components. We introduce SComm, a real-time mutually authenticated secure communication framework that consists of a commitment-based enrolment protocol and a mutually authenticated key establishment protocol by which components can authenticate each other and carry out secure communication to prevent DoS attacks. Our framework applies a Zero-Knowledge Elliptic Curve Diffie-Hellman (ZK-ECDH) to establish a unique cryptographic session key for secure communication. We analysed our framework with respect to its security and performance, and the results show that our frame-work enhances the security of components and communication in real-time to efficiently deal with unauthentication and DoS attack. As proof of concept, we apply our framework to mitigate the DoS attacks at the registered entity.
This work is concerned with the study of the extreme rays of the convex cone of $3\times 3$ quasiconvex quadratic forms (denoted by ${\cal C}_3$). We characterize quadratic forms $f\in {\cal C}_3,$ the determinant of the acoustic tensor of which is an extremal polynomial, and conjecture/discuss about other cases. We prove that in the case when the determinant of the acoustic tensor of a form $f\in {\cal C}_3$ is an extremal polynomial other than a perfect square, then the form must itself be an extreme ray of ${\cal C}_3;$ when the determinant is a perfect square, then the form is either an extreme ray of ${\cal C}_3$ or polyconvex; and finally, when the determinant is identically zero, then the form $f$ must be polyconvex. The zero determinant case plays an important role in the proofs of the other two cases. We also make a conjecture on the extreme rays of ${\cal C}_3,$ and discuss about weak and strong etremals of ${\cal C}_d$ for $d\geq 3.$ where it turns out that several properties of ${\cal C}_3$ do not hold for ${\cal C}_d$ for $d>3,$ and thus case $d=3$ is special. These results recover all previously known results (to our best knowledge) on examples of extreme points of ${\cal C}_3$ that were proved to be such. Our results also improve the ones proven by the first author and Milton [20].
With the fast development of the electric vehicle (EV) technology, EVs are expected to be the mainstream in future. The large number of EVs facilitate development of the emerging vehicle-to-grid (V2G) technology, which realizes two-way electricity flows between EVs and the power grid. How to achieve fairness and privacy for EVs during electricity/service exchanges remains a challenging problem for V2G. In this article, we propose a privacy-preserving fair exchange schemeV2GExfor V2G based on the blockchain. V2GEx is composed of an extended blockchain that supports zero-knowledge funds, a fair exchange smart contract based on the hashchain micropayment mechanism, and a privacy-preserving protocol for V2G. We further propose a simpler and more efficient scheme called Uni-V2GEx, which preserves privacy for only one party. We also provide a rigorous security proof under the universal composability (UC) model to prove V2GEx's security. To evaluate its efficiency, we implement V2GEx and conduct comprehensive experiments to test its performance in terms of computation cost and processing delay. The experiment results show that V2GEx is highly efficient in that verification of V2GEx transactions costs only 20 ms and the average transaction processing latency is around 6 seconds in a 200-node blockchain network.
This work formalizes Publicly Auditable Conditional Blind Signatures (PACBS), a new cryptographic primitive that allows the verifiable issuance of blind signatures, the validity of which is contingent upon a predicate and decided by a designated verifier. In particular, when a user requests the signing of a message, blinded to protect her privacy, the signer embeds data in the signature that makes it valid if and only if a condition holds. A verifier, identified by a private key, can check the signature and learn the value of the predicate. Auditability mechanisms in the form of non-interactive zero-knowledge proofs are provided, so that a cheating signer cannot issue arbitrary signatures and a cheating verifier cannot ignore the embedded condition. The security properties of this new primitive are defined using cryptographic games. A proof-of-concept construction, based on the Okamoto–Schnorr blind signatures infused with a plaintext equivalence test is presented and its security is analyzed.
The bicuspid aortic valve (BAV) still hides many challenging issues including definition and classification. Michelena et al. [1] present an interesting new, very comprehensive, partially complex BAV classification and beyond in written English, avoiding numbers and letters for a universal, audience. Included are 3 basic types: the fused BAV, the 2-sinuses BAV and the partial-fusion BAV (form fruste), and also aspects like fusion versus raphe, indeterminate fusion, fusion orientation, cusp symmetry and aortopathy. For everyday clinical purposes, this classification appears a little impractical compared to other classifications (see Table 1 in [1]) including that, published by our group, Sievers and Schmidtke [2]. From clinical experience, we defined a congenital aortic valve anomaly as a BAV when it presents with a fishmouth like, bifoliate, functionally biscupid systolic valve opening, validated at surgery in adults, independent of empryological considerations. Three basically different phenotypes were observed: the genuine BAV with 2 sinuses and 2 cusps but no raphe (BAV type 0, whereby a raphe was defined as a fibrous or calcified ridge extending from the wall to the free edge of the cusps), followed by phenotypes (similar to tricuspid valves), with 3 sinuses and 3 cusps, 2 of which are conjoined in 1 raphe (BAV type 1), and consequently a phenotype with also a bifoliate opening, 3 sinuses, 3 cusps but 2 raphes (BAV type 2). Although not yet observed in mice or hamsters it may surface as a member in the spectrum of endocardial cushion defects, typical for BAV’s, underlined by an earlier report, describing it as a unicuspid valve with 2 raphes ‘representing abortive commissures’, which is not the original unicuspid valve [3]. Lack of finding this entity in animals is not necessarily proof that it does not exist in human beings. As the main category, the number of raphes allowed for classifying the 3 groups with short, practical and memorable expressions (BAV type 0, BAV type 1 and BAV type 2), the essence of clinical classifications (e.g. Stanford A/B, de Bakey I, II, III). The subcategory includes letters for orientation e.g. L: left-, R: right-, N: non-coronary sinus. Thus, the numbers of the BAV types correspond to concrete BAV typical structures—the raphes—facilitating identification and clinical connotations. For example, BAV type 0: the Ross operation and even the implantation of conventional substitutes could be less straightforward, because of only 2 commissures. Repair is facilitated. The most frequent BAV type 1, L-R: how to manage the discrepancy between the more downstream displaced smaller left and right cusps and the more upstream located larger non-coronary cusp during the Ross operation, repair, remodelling, reimplantation or even replacement with conventional prostheses preventing leaflet prolapse or tilt? Since cusp symmetry seems favourable for repair, the question comes up how to achieve the ideal length of the cusps, 1.6 times the diameter is necessary (1.1 in tricuspid valves) to warrant a stenosis free valve opening without prolapse (commissural elongation, or windmill excessive cusps tissue?) BAV type 2: the nadirs of the 3 sinuses are at 1 plane facilitating valve replacement but rendering repair more complex. Furthermore, considering the complex BAV pathology and the excellent long-term results with surgery, warranting secure fixation of the prosthesis and concomitant aortic surgery, transcatheter aortic valve replacement may be applied carefully and benefit from BAV-specific management or even design innovations. Also, BAV development is complex, probably not single gene related, influenced by epigenetics such as embryonic blood flow and sometimes including also the myocardium, the ascending aorta and the mitral valve [4, 5]. Basically, endocardial cushions seem to be involved. As a novel mechanism of BAV development, displaced aortic intercalated valve swellings in human embryos were reported recently [6], possible correlating with our observation (see above) of displaced left and right coronary cusps in BAV type 1, L-R. BAV-associated aortopathy (AoP) also emerges with many questions, e.g. how is it best defined, and optimally treated? Fact is, AoP rarely presents with symptoms except when catastrophic aortic dissection occurs. This renders AoP surgery more prophylactic. Because it is predominantly performed at BAV surgery, indication and surgery are challenging since the dilatation of the aorta ascending often tapers into the arch [7]. The association of AoP and BAV seems overall weak [7]. Including haemodynamics in the analysis reveals ascending AoP more associated with stenotic BAVs, probably shear stress-related. Insufficient BAVs are associated with more extensive AoP [7], obviously more gene related inducing surgical implications for adequate reinforcement and replacement. Latest after Rylski et al. [8] reported a mean ascending aorta diameter of only 40 mm, measured within 2 years prior to dissection, other parameters in addition to size surface significant for decision-making, such as age, z-score, particularly history, growth rate, intraoperative tissue quality, haemodynamics, BAV type, and in the future potentially genes, blood pressure at rest and exercise, etc. First clinical results with this more individualized concept for treatment of the ascending aorta at BAV surgery are promising [9]. In this respect, calculation of the place value of each single variable and at the end the total personal risk, optimized by computational biology, may assist decision-making [10]. Also, surgical risk reduction to near zero; flexible, individually shaped prostheses; intraoperative histological analysis; automatical anastomoses, etc, are desirable goals. Proper communication is necessary, preferably accompanied either by novel classifications or evolving already used classifications with new knowledge or speciality requirements, e.g. adding the angle between the fused and non-fused cusps in degree indicating symmetry for repair purposes (BAV type 1, L-R, 150°), or the extend of fusion in %, a tissue quality score or a calcification score for transcatheter aortic valve replacement. However, in the clinical setting, more extended, complex classifications are less user friendly, potentially causing confusion. Often only short, concise, practical, partially idealized, but memorable expressions with speciality and clinical relevance and connotations are advantageous. Paying attention to these facts has probably made our classification [2], particulary the BAV type 0 and the BAV type 1, the so-called Sievers classification [1] popular and widely used. Anyway, progress in decrypting the BAV mystery, may profit from fruitful discussions including different definitions and classifications, their supposed limitations and benefits. (Babel also positive?) Only audience and time will tell.
Biometric verification has been widely deployed in current authentication solutions as it proves the physical presence of individuals. To protect the sensitive biometric data in such systems, several solutions have been developed that provide security against honest-but-curious (semi-honest) attackers. However, in practice attackers typically do not act honestly and multiple studies have shown drastic biometric information leakage in such honest-but-curious solutions when considering dishonest, malicious attackers. In this paper, we propose a provably secure biometric verification protocol to withstand malicious attackers and prevent biometric data from any sort of leakage. The proposed protocol is based on a homomorphically encrypted log likelihood-ratio-based (HELR) classifier that supports any biometric modality (e.g. face, fingerprint, dynamic signature, etc.) encoded as a fixed-length real-valued feature vector and performs an accurate and fast biometric recognition. Our protocol, that is secure against malicious adversaries, is designed from a protocol secure against semi-honest adversaries enhanced by zero-knowledge proofs. We evaluate both protocols for various security levels and record a sub-second speed (between $0.37$s and $0.88$s) for the protocol against semi-honest adversaries and between $0.95$s and $2.50$s for the protocol secure against malicious adversaries.
This personal reaction is written from multiple perspectives. First and foremost, as the corresponding author of the original FAIR article. Second as the chair of the first High Level Expert Group (HLEG) of European Open Science Cloud (EOSC) (which is how I met Jean-Claude) and third from my current GO FAIR and CODATA perspective. None of what I write below is to be seen as a formal position of any of the organisations I am associated with.Let me start by stating that, after some periods silent of hope and of deep despair, I now strongly feel that, with the governance of the EOSC Association in place, EOSC will become a success after all. It will still be critical that the Association involves the member states (MSs) and actual researchers in an agile and non-bureaucratic manner, for which we need bottom-up mechanisms such as operated by the Research Data Alliance (RDA) and GO FAIR. But a balancing formal entity operating along the formalised Strategic Research and Innovation Agenda [1] and the Partnership proposal as well as the various “declarations” including the recent one under the German presidency [2] are an excellent guiding roadmap to a successful EOSC, obviously in global context.That said, at the risk of sounding like broken record, this reaction should also look at the points where it went “almost” wrong, as we should try and learn from our mistakes. I may make some enemies—or strengthen the opinion of existing ones—in the process, but then, a wise old friend, who also wrote one of the reactions once told me: “Barend, unless you made some enemies you probably lived in vain.” So I will speak my mind (“what's new'?). I also like to say that ”EOSC“ brought me some real new friends for life!First of all, the fact that quickly after its inception FAIR became a hype term①, which was probably partly even accelerated by the prominent role it played in early EOSC discussions with EC's Director General, also has its downsides. Like for the term “AI”, everyone co-opts the term and some start watering the concept down to a bloodless caricature from what it originally meant. In the case of FAIR this includes removing the central notion of machine actionability, mis-characterising it as a standard, conflating it with “open”, only linking it to data sensu stricto, ignoring software, algorithms and more. In general terms, people that sometimes seem to have never read the original article [3], the most flagrant abuse of the term I have heard (obviously not from an active researcher) is this: “If data are Findable, Accessible and Interoperable it is ”automatically' Reusable.“ This is of course ”swearing in FAIR church“ as the R (principles R1–3) [3] clearly state that rich provenance and reuse conditions are critical and in particular the provenance. The decision whether (even high quality) data are fit for purpose (reuse in a particular study) is a critical step and is imho (in my humble opinion) at the basis of the reproducibility problem we currently face. Therefore, I would like to re-emphaisize here my current one liner to summarise the aim of the FAIR guiding principles: ”The Machine Knows what I mean“. Those who feel that FAIR is too ambitious and for instance promote that ”achieving F and A is enough for now“ in my humble opinion fail to see the disruptive character of the solutions we need to make EOSC and its sister around the globe a real paradigm shift towards Open Science (OS). Or they are just trying to preserve the status quo and move incrementally at a pace they can follow.This nicely bridges to the first observation on EOSC as such. I indeed think that the first “Communication” that needed 126 iterations mentioned by Jean-Claude, which happened in the same time frame as our “HLEG-1” period, was symptomatic for a basic flaw in the discussions, which haunts us still today. Conflating the “ICT”/HPC (or basic e-infrastructure) with the data and end user applications for analytics, has caused an enormous hurdle. In the entire journey of the HLEG we had to carefully navigate around this cliff and it is still a highly controversial issue today. This part was the “Dunning Kruger effect” [4] pur sang: The “other side is easy” (because I am not hindered by any knowledge about it) and is “more or less already done” (because I do not understand the complexity). This is not only true for the active researchers who cannot use the current e-infrastructure efficiently (and naturally that is “entirely the fault of the nerds who build things I do not understand or cannot operate”), but also for e-infrastructure engineers who know everything about ICT and “thus” (?) also about data (because “that is just ones and zeros”) as Jean- Claude also noted. I also believe however, that it is a mistake to completely separate e-infrastructure for the data and services layer, as the e-infrastructure should route (and understand at least at middleware level) what processes are needed on the data and how the FAIR services “run”. Nowadays (after many iterations) I use the diagram below (Figure 1) to explain that all three basic elements of the “Internet of FAIR Data and Services” are needed. Each of them should be adorned with FAIR (machine actionable) metadata to seamlessly form a Web of FAIR Data and Services on top of the current, proven Internet backbones, thus forming the “Internet of FAIR Data and Services”, eventually creating an “Internet for Social Machines” [5] where people and machines can both efficiently use all services, independently and in collaboration.This does absolutely not mean that the foundation (e-infrastructure) of the triangle is “trivial” or “can be reused as is”. Not only middleware, but also the crucial and fundamental concept of FDOs needs to be developed in close collaboration between data and computer experts and is largely domain-agnostic.The seamless combination will become the principle “package” of information that machines (and also people) can understand and act upon. Major infrastructure builders should actually co-lead this, while domain scientists need to decide on which data formats and metadata schemes (i.e. FAIR Implementation Profiles [9]) should be built on this basic schema.Together with the Dunning Kruger effect, too many overlapping and redundant projects supporting the talking/meeting/landscaping, re-landscaping and re-re landscaping' has resulted in what I became to call the “EOSC is a bigger Me syndrome”. On the one hand, countless people voluntarily invested (and still invest) their time in the development of the EOSC, but others seem to only see EOSC as “yet another way to collect EC funding for their current solutions that are in my opinion not future- and OS proof. This misbalance between people investing their own time and effort based on intrinsic motivation and vision and on the other hand the ”reliance on EC subsidy“ caused a dichotomy during the scoping years of EOSC between disruptive and ”preservative“ approaches. The heavy reliance on EC subsidy also largely ignored the subsidiarity principle [10] and the fact that 90% of the eventual infrastructures and services that we need for EOSC will be paid by the MSs. Also data and research intensive industry was largely kept out of the loop, which was another mistake I have frequently pointed out. This helped to create and sustain the ”Brussels Bubble“ that Jean-Claude described. The Association will hopefully reverse that trend.Finally, the influence on the HLEG report of the then-commissioner was rather profound. The report was not only delayed almost 6 months after its proposed publication version, but there is also a nice additional “untold story” here: The originally proposed title of the report was: “A Cloud on the 2020 Horizon”. In my original foreword I explained the slightly “glooming” connotation of that title. When the report was finally approved, it appeared that the title had been unilaterally changed into “Realising A European Open Science Cloud [11]”. Not only did I have to hastily change my foreword (because it made no sense anymore) but also, my notorious statement that the “result” should neither be “European” (only), nor Open (only) nor (only) for Science and certainly not (just) a “Cloud” was entirely ignored in changing that title. But it again emphasises the “This is an EC thing” context, with the associated risk for confiscation of the concept by the “usual suspects” in EC subsidy land. However, I feel after three years of intensive deliberations, which may be considered lightning fast on the geological time scale, see George's reaction, we can conclude that most of the original HLEG recommendations are well-represented in the basic guiding documents of the EOSC Association, which makes me a happy man at the end of this crazy year.That leads me to the final observation: As a result of the (quote from Jean-Claude): “non-paper seen as the political turning point in support of EOSC” [12], GO FAIR (Global Open FAIR) [13] was started, originally by Germany and The Netherlands and soon joined by France as a temporary “kick-start”, bottom-up approach to accelerate EOSC (see also recommendation I-2.1. in the HLEG report, annex 1).Soon, GO FAIR became really global and the agile modus operandi of practical Implementation Networks yielded a number of crucial approaches to speed up the adoption of the FAIR guiding principles and the hourglass approach [14]. Now, late 2020, when the EOSC Association is a fact, GO FAIR (1.0) has achieved its goals (early implementation steps) and we need to reflect on its future. Next to the intrinsic value of the active GO FAIR IN community [15] as such, several particular assets that I need to mention here are the development of the FAIR Implementation Profile and Metadata4Machines approach, the development of easy to install FAIR data points for open, FAIR metadata publication and indexing, and last but not least the international effort (involving many players, also outside the direct GO FAIR initiative) to develop the minimal specs of the FDO framework [7] in a more specified form than when coined in the FAIR expert group report [5]. These assets (all open source and open access) can be carried over, not only to EOSC, but will have much wider, international, impact most likely leading to a continuation of GO FAIR (2.0) beyond its original time scope, namely three years, the predicted time it would take to complete the international policy and bureaucracy process to reach the status of a formal association as we have today. I hope the leaders of the Association will optimally learn from the successes and failures and near-road-accidents of the last three years and see EOSC as the European contribution to a “Global Open Science Commons”, also known as the Internet of FAIR Data and Services, in full, open collaboration with the international organisations that are now joining forces in the Data Together initiative [16]. After all, the major challenges we face are global, so is the research needed to face them and so are the solutions we hope to fiend. I fully trust the current leadership of the association to make that vision reality.Policy recommendationsGovernance recommendationsImplementation recommendations
In the area of cloud computing, data deduplication enables the cloud server to store a single copy of data by eliminating redundant files to improve storage and network efficiency. Proof-of-ownership (PoW) is a cryptographic function that verifies the user who really owns the data. Most of the existing schemes have tried to solve the deduplication problem by providing the same encryption key for identical data. However, these schemes suffer from dynamic changes in ownership management. In this paper, we propose an in-line block matching (IBM) protocol based on zero-knowledge proof for deduplication with dynamic ownership management, which eliminates the unauthorized access of sensitive data. In this proposed work, for a new file, the uploader randomly chooses a file encryption key and encrypts the file. The user also computes a unique proof for the uploaded file by dividing the file into number of blocks and stores this proof to the cloud server. The cloud server computes the group key for the ciphertext and re-encrypts it using this group key. The cloud server also does the proof verification against the subsequent uploader for an existing file. The cloud server is honest-but-curious, so the proposed scheme confirms that the cloud server does not know any information about file encryption key even though it plays a proxy role. The result shows that our proposed scheme protects the data from both cloud server and adversaries. Also, the computational cost is comparatively less than other existing schemes.
This article presentsLiteZKPa framework for supporting multiple anonymous payments using a smart contract-based zero-knowledge proof (ZKP) protocol on resource-limited devices. Specifically, to address challenges related to minimizing the computational overhead and offer a fully anonymous system,LiteZKPincludes novel schemes such a new merkle tree mechanism to reduce the burden of ZKP operations, and integrates smart contract-based ZKP with an off-chain payment channel to reduce the amount of ZKP operations when performing continuous data exchange. We present evaluation results ofLiteZKPfrom both PC-scale and resource-limited client devices and our results suggest thatLiteZKPreduces the latency and energy consumption by more than 55% on Internet of Things (IoT)/mobile edge computing platforms, while requiring only 8% of block processing fee compared to a naive ZKP-based scheme.
As an underlying technology and infrastructure, blockchain creates great value when combining with other emerging information technologies, such as Artificial Intelligence, Big Data Analysis, Cryptography Technology. Although the blockchain system has been contunuously upgraded in recent years, current blockchain still has its deficiency in terms of node control and privacy protection. First of all, the high existence rate of malicious nodes in the chain made it difficult to well purify the network environment, meanwhile the malicious nodes cannot be easily dealt with. Secondly, the correlation between nodes can still be discovered through analysis. As a result, the privacy of users' information cannot be well protected. This paper proposes a distributed identity authentication scheme based on Zero-knowledge proof, which uses face recognition technology to ensure the uniqueness and legitimacy of identity and control the generating of malicious nodes; Zero-knowledge proof algorithm is used to encrypt and support face data to prevent user identity information from being disclosed. At the same time, the linkable ring signature algorithm is adopted to confuse the correspondence between nodes and private information to further protect users' privacy information.
Blockchain Technology Applications and Security
Cryptography and Data Security
Advanced Steganography and Watermarking Techniques
Electronic voting systems have several necessarily requirements, such as anonymity that others cannot link voters with votes, the fairness that votes should not be leaked before the tally, and the accuracy that eligible voters' votes should be counted correctly. There have been proposed various methods to realize the requirements. Some of them require anonymous communication paths as necessary elements to satisfy the anonymity requirement for a practical electronic voting system. Cruz et al. proposed an electronic voting system that does not need anonymous communication paths, using Bitcoin, a cryptographic currency, as a distributed database. However, Bitcoin is a system in which all data are disclosed, and anyone can check what exchanges a person of a certain ID (Bitcoin address) has done. It is possible to reveal which voter made what vote, and hence(anonymity is not satisfied. In this paper, we propose a method to solve the above problem by using Bitcoin mixing. We propose an electronic voting system using Zerocoin, a variant of Bitcoin, as a database, in which zero knowledge proof is used instead of blind signature for mixing.
The types of political and policy knowledge required to guide rapid transition to low-carbon economies remain largely disconnected in the fields of political science, psychology, and sociology. The composition and key features of the main actors involved, and their relationships have also not been systematically described. This paper attempts to address these knowledge gaps by proposing a new, integrative typology of actors involved in climate change mitigation policy in the United Kingdom (UK) and a method for mapping these actors and selecting their typological descriptors onto a 2D space. The mapping method enables stakeholders to visualise and evaluate the strength of support for the UK government’s net-zero-by-2050 “green growth” strategy and the tensions, challenges, and strategic opportunities potentially facing more radical alternatives. The methodology could be replicated for climate actors in other countries and, in principle, for any geographical scale or level of governance.
Chao Lin, Min Luo, Xinyi Huang, Kim‐Kwang Raymond Choo · 5 authors
Credit system is generally associated with the banking and financial institutions, although it has far reaching implications for residents of countries, such as U.S., particularly for those with a poor credit history. Specifically, a credit score computation (CSC) quantifies an individual’s credit value or credit risk, which is used by banking and financial institutions, as well as other entities (e.g., during purchasing of insurance policies and application of rental properties), to facilitate their decision-making (e.g., whether to approve the insurance policy purchase or the level of premium). Although a number of CSC models have been proposed in the literature for supporting different application scenarios, privacy protection of CSC is rarely considered despite the potential for leakage of user private information (e.g., registration, hobbies, credit, relationships, and inquiry). Such information can then be abused for other nefarious activities, such as identity theft and credit card fraud. Thus, in this article, we first analyze the privacy strength of existing CSC models, prior to presenting the formal definition of a privacy-preserving CSC system alongside its security requirements. Then, we propose a concrete construction based on Paillier encryption with three proposed noninteractive zero-knowledge schemes. To demonstrate feasibility of our proposal, we evaluate both its security and performance.