Privacy of blockchains has been a matter of discussion since the inception of Bitcoin. Various techniques with a varying degree of privacy protection and complexity have been proposed over the past decade. In this survey, we present a systematic analysis of these proposals in four categories: (i) identity, (ii) transaction, (iii) consensus, and (iv) smart contract privacy. Each of these categories have privacy requirements of its own, and various solutions have been proposed to meet these requirements. Almost every technique in the literature of privacy enhancing technologies have been applied to blockchains: mix networks, zero-knowledge proofs, blind signatures, ring signatures, secure MPC, homomorphic encryption, to name just a few. We analyze each category separately in the paper. We first define the related privacy issues, and then review the proposed solutions. The limitations of each solution and the attacks discovered are also discussed along with the proposals. For each category, we first define the relevant privacy issues, and then review the proposed solutions along with their features and limitations
Abelian cellular automata (CAs) are CAs which are group endomorphisms of the full group shift when endowing the alphabet with an abelian group structure. A CA randomizes an initial probability measure if its iterated images have weak*-convergence towards the uniform Bernoulli measure (the Haar measure in this setting). We are interested in structural phenomena, i.e., randomization for a wide class of initial measures (under some mixing hypotheses). First, we prove that an abelian CA randomizes in CesĂ ro mean if and only if it has no soliton, i.e., a non-zero finite configuration whose time evolution remains bounded in space. This characterization generalizes previously known sufficient conditions for abelian CAs with scalar or commuting coefficients. Second, we exhibit examples of strong randomizers, i.e., abelian CAs randomizing in simple convergence; this is the first proof of this behaviour to our knowledge. We show, however, that no CA with commuting coefficients can be strongly randomizing. Finally, we show that some abelian CAs achieve partial randomization without being randomizing: the distribution of short finite words tends to the uniform distribution up to some threshold, but this convergence fails for larger words. Again this phenomenon cannot happen for abelian CAs with commuting coefficients.
We consider the problem of single-round private information retrieval (PIR) from N replicated databases. We consider the case when B databases are outdated (unsynchronized), or even worse, adversarial (Byzantine), and therefore, can return incorrect answers. In the PIR problem with Byzantine databases (BPIR), a user wishes to retrieve a specific message from a set of M messages with zero-error, irrespective of the actions performed by the Byzantine databases. We consider the T-privacy constraint in this paper, where any T databases can collude, and exchange the queries submitted by the user. We derive the information-theoretic capacity of this problem, which is the maximum number of correct symbols that can be retrieved privately (under the T-privacy constraint) for every symbol of the downloaded data. We determine the exact BPIR capacity to be C = (N -2B)/N·(1-T/(N-2B))/(1-(T/(N - 2B))M), if 2B + T <; N. This capacity expression shows that the effect of Byzantine databases on the retrieval rate is equivalent to removing 2B databases from the system, with a penalty factor of (N - 2B)/N, which signifies that even though the number of databases needed for PIR is effectively N - 2B, the user still needs to access the entire N databases. The result shows that for the unsynchronized PIR problem, if the user does not have any knowledge about the fraction of the messages that are missynchronized, the single-round capacity is the same as the BPIR capacity. Our achievable scheme extends the optimal achievable scheme for the robust PIR (RPIR) problem to correct the errors introduced by the Byzantine databases as opposed to erasures in the RPIR problem. Our converse proof uses the idea of the cut-set bound in the network coding problem against adversarial nodes.
It is believed that automated valet parking (AVP) system has great potential to mitigate the parking headache for the future smart city, as it can provide on-demand parking services, bringing immense benefits from energy saving for vehicles to time saving for drivers. For an AVP system, parking reservation is an indispensable part so that vehicles can accomplish automated parking in accordance with the reserved parking information. However, the reservation requests may not only reveal the driver identity, but also disclose his/her sensitive locations, e.g., the most visited places, which are of great concerns to users. To deal with this challenge, the anonymous techniques can be naturally applied during parking reservation, but directly applying the anonymous techniques in AVP will introduce a new security issue, i.e., the anonymous user may maliciously crash the AVP system by repetitively sending the reservation requests, which is called âdouble-reservation attack.â In this paper, we propose a new privacy-preserving reservation scheme for securing AVP system. Specifically, each anonymous user must have only one valid reservation token at any moment, and the token can only be used for booking one vacant parking space once. The proposed scheme does not only preserve the user's identity privacy and location privacy but also prevents the âdouble-reservation attackâ based on several elegant building blocks, i.e., zero-knowledge proofs of knowledge and proxy resignature. Detailed security analysis confirms the security properties of our proposed scheme. In addition, extensive simulations are conducted to compare our proposed scheme with three previous schemes, and the experiment results demonstrate that our scheme is also much efficient in a WiFi-based testbed.
In this paper, we propose a new method to perform Sparse Kernel Principal Component Analysis (SKPCA) and also mathematically analyze the validity of SKPCA. We formulate SKPCA as a constrained optimization problem with elastic net regularization (Hastie et al.) in kernel feature space and solve it. We consider outlier detection (where KPCA is employed) as an application for SKPCA, using the RBF kernel. We test it on 5 real-world datasets and show that by using just 4% (or even less) of the principal components (PCs), where each PC has on average less than 12% non-zero elements in the worst case among all 5 datasets, we are able to nearly match and in 3 datasets even outperform KPCA. We also compare the performance of our method with a recently proposed method for SKPCA by Wang et al. and show that our method performs better in terms of both accuracy and sparsity. We also provide a novel probabilistic proof to justify the existence of sparse solutions for KPCA using the RBF kernel. To the best of our knowledge, this is the first attempt at theoretically analyzing the validity of SKPCA.
Security of data is crucial in nowadays societies. One of the most basic security protocols are the zero-knowledge protocols where a prover convinces a verifier of the knowledge of a secret information without revealing that piece of information. The tradicional approach to prove the security of these protocols is based on the (im)possibility of simulation of the interactions. A more fundamental way to prove the security is based solely on the information conveyed about proof. In order to establish that connection and quantifying the number of possible transformations that one can use in these protocols, we use Kolmogorov complexity and in particular we focus on the incompressibility theorem. In this paper we study the counterpart of this theorem by, instead of providing the number of x such that for a fixed y, Kt(x|y) â Kt(x), we study for a fixed y the number of x such that Kt(x|y) â Kt(x). As a second contribution of this paper we present an extension of the results regarding Kolmogorov one-way functions started in [3]. This cryptographic primitives have the property to be easy to compute but hard to invert and are a basilar ingredient for digital security.
Ross Guttromson, Stephen Verzi, Lon Andrew Dawson, Drew Levin · 10 authors
This project explored coupling modeling and analysis methods from multiple domains to address complex hybrid (cyber and physical) attacks on mission critical infrastructure. Robust methods to integrate these complex systems are necessary to enable large trade-space exploration including dynamic and evolving cyber threats and mitigations. Reinforcement learning employing deep neural networks, as in the AlphaGo Zero solution, was used to identify "best" (or approximately optimal) resilience strategies for operation of a cyber/physical grid model. A prototype platform was developed and the machine learning (ML) algorithm was made to play itself in a game of 'Hurt the Grid'. This proof of concept shows that machine learning optimization can help us understand and control complex, multi-dimensional grid space. A simple, yet high-fidelity model proves that the data have spatial correlation which is necessary for any optimization or control. Our prototype analysis showed that the reinforcement learning successfully improved adversary and defender knowledge to manipulate the grid. When expanded to more representative models, this exact type of machine learning will inform grid operations and defense - supporting mitigation development to defend the grid from complex cyber attacks! This same research can be expanded to similar complex domains.
Open access
Smart Grid Security and Resilience
Distributed and Parallel Computing Systems
Infrastructure Resilience and Vulnerability Analysis
The redesign of cloud storage with the amalgamation of cooperative cloud and an immutable and unhackable distributed database blockchain thrives towards a strong CIA triad and secured data provenance. The conspiracy ideology associated with the traditional cloud has economized with cooperative cloud storage like Storj and Sia, decentralized storage, which allows renting the unused hard drive space and getting monetary compensation in an exchange with cryptocurrency. In this article, the authors explain how confidentiality, integrity and availability can be progressed with cooperative cloud storage along with tamper-proof data provenance management with ethereum smart contracts using zero-knowledge proof (ZKP). A contemporary architecture is proposed with regards to storing data on the cooperative cloud and collecting and verifying the provenance data from the cloud and publishing the provenance data into blockchain network as transactions.
As CKD progresses, the capacity of the kidneys to eliminate metabolic waste is gradually lost, resulting in the retention of a host of compounds. Many of these solutes affect biologic functions and are likely contributing to the uremic syndrome, affecting not only morbidity and mortality but also patient-centered outcomes (fatigue, pruritus, sleep disorders) and quality of life (1). Our knowledge on the nature and action of the uremic compounds is still expandingâa progress at least partly attributable to the acquisitions of metabolomic analysis, which allows the blinded search for previously unknown molecules (2). The intensive exploration of the role of the intestine in the generation of uremic toxins was set in motion only during the past decade (3). The chain of events at play generally begins with dietary protein degradation followed by the metabolic transformation (fermentation) of amino acids by the gut microbiota and their conjugation (mostly sulfatation and glucuronidation) in the intestinal wall or liver by phase 1 and phase 2 metabolizing enzymes. Conjugation is, essentially, intended to increase solubility and neutralize toxicity, but the latter effect may remain incomplete, as several end-products still exert toxicity (4). In the search for intestinally generated uremic solutes, some proof-of-concept metabolomic studies identified a number of discriminators by comparing plasma or urine from either germfree rodents with control animals (5) or human subjects with and without a colon (6). Several identified molecules appeared to be known protein-bound uremic toxins, such as indoxyl sulfate, p-cresyl sulfate, and phenyl sulfate. In this issue of the Clinical Journal of the American Society of Nephrology, Mair et al., in their study on patients on dialysis with and without a colon, used a slightly different approach than in their previous study (6), resulting in a considerable extension of our knowledge on uremic solutes of intestinal origin (7). A sophisticated analytic platform comparing urine of patients with normal kidney function with or without colon yielded 91 colon-derived molecules. This selection was then narrowed by comparing the plasma of controls with that of patients on maintenance hemodialysis, resulting in a definite list of 60 intestinally generated uremic solutes. By using a chemical reference library, Mair et al. (7) could then define the structure of 34 of these substances, among which 22 were classified as newly detected intestinally generated retention products. Many (but not all) of these solutes were protein bound and/or sulfates, glucuronides (as demonstrated by sample sulfatase treatment), or metabolites of phenyl acetic acid. For the majority of compounds of which it was possible to calculate kidney clearance, this parameter exceeded creatinine clearance. As the latter can be considered a proxy of GFR, this suggests substantial active kidney tubular secretion, and may cast some doubts on the value of GFR as an all-inclusive measure of kidney function. The question is how this considerable extension of knowledge can be applied for the better to improve the quality and sustainability of the treatment and life quality of patients with kidney failure. One point is certain: the idea that the uremic syndrome is a simple condition, resulting from the activity of one or a few retention solutes, is further away than ever. It seems tempting to embark upon a large experimental effort to unravel the toxicity of the newly detected solutes, but such an endeavor should not be underestimated. Next to the identification of the solutes per se, the uremic concentration needs to be determined which necessitates the availability of the pure compound (either purchased or synthesized) before the biochemical impact can be tested, preferably in several appropriate organ or cell systems (4). Such approach may be extremely time-consuming unless well designed, high-throughput systems can be applied. The number of solutes to be tested could, however, be reduced on the basis of data from large sample collections and big data analysis, taking into consideration hard outcomes as well as patient-centered end points. In addition, systems biology could be used to unravel interactions among metabolites, the most important pathways involved and the most important metabolites. Another option could be the selection of solutes with the most outspoken characteristics, e.g., the largest concentration gap between normal and hemodialysis or between those with and without a colon, or those solutes with the highest tubular secretion. Perhaps more importantly, the reported data may help guiding the development of novel therapeutic procedures. As the study by Mair et al. detected large clusters with common characteristics (sulfates and glucuronides; phenols, cresols, and indoles), these could be approached by specific sorption methods aimed at capturing these structures. If such methods can be developed, they could also help to offer proof of concept regarding whether removing those solutes improves outcomes. Another option suggested by this study is correction of the intestinal dysbiosis by modifying intestinal bacterial metabolism, for which several proof-of-concept studies are already available, applying different diets, probiotics, prebiotics, synbiotics, or antibiotics (8). However, it might be dangerous to jump to conclusions. When Mair et al. considered the urinary excretion ratio of patients without a colon versus controls per individual molecule, it almost always exceeded zero (7), suggesting extraintestinal sources. Likewise, even if one does not account for the five patients with an ileal pouch, which appears to preserve some intestinal microbial activity, more than 20 intestinally generated uremic solutes were found in the urine of some patients and seven were found in all patients without a colon. Also for other reasons, targeting the colon as an isolated effort may offer an insufficient response to the uremic problem. A recent classification on the basis of preset criteria summing up 24 uremic solutes with the most important biochemical and clinical impact (9) contained only four of the solutes retrieved in the analysis of Mair et al. (7) (indoxyl sulfate, p-cresyl sulfate, trimethylamine-N-oxide, and indole acetic acid). This does not exclude yet unproven toxicity of some of the newly retrieved solutes by this study (7), but does suggest that a large number of solutes with toxic potential may not be entirely of intestinal origin. Of note, the aggregated results of the study by Mair et al. (7) also point to the role of an axis comprising the intestine, liver, plasma protein binding, and tubular excretion, rather than one of the intestine alone. All these observations might translate into difficulties to sufficiently reduce concentration of the concerned solutes by applying intestinal methods only. Tackling the intestine may be one of the solutions, but it is not the only solution. Subsequently, research efforts should be continued and strengthened to develop also other alternative ways to enhance toxin removal, such as decreasing protein binding, sorption, preservation of kidney function, increasing tubular secretion, and applying various acquisitions at the intersection of kidney replacement therapy and regenerative medicine (bioartificial kidney) or regenerative medicine per se (stem cells, organoids, bioengineered kidneys). Stimulating research in these areas is an important task for the nephrological community and all those involved in health policy, as patients, their families, and health professionals are in need of innovations in a field that has stagnated for too long and has too high amounts of health expenditures in its current form. In this context, targeting the intestinal microbiome remains a cheap and noninvasive therapeutic option, with a potential outreach to a large number of patients. In spite of the impressive efforts to accomplish this analysis and the vast amount of information offered, the study by Mair et al. (7) unavoidably raises some questions and concerns. Regardless of the comforting double-check of the reliability of the data provided for the most familiar uremic solutes, mass spectrometric analysis as used here remains semiquantitative, which may be a source of error, especially for calculated values such as clearances, ratios, or free fractions. Also, the use of spot urines sometimes necessitating drastic dilution is a potential source of error. Some seemingly obvious colon-derived candidate molecules, such as indoxyl glucuronide, hippuric acid, or phenyl acetic acid, that were traced by other metabolomic studies, sometimes by the same group (6), were absent in this analysis, which makes one suspect that either analytical bias or individual differences in nutritional status, metabolism, or genetics, may affect the findings. Other potentially skewing factors may be the overwhelming majority of patients with CKD and those on hemodialysis suffering from diabetes versus none in the control and colectomy groups, or the presence in the colectomy group of patients on immunosuppressive agents, as both may modify the intestinal microbiome (10,11). In conclusion, this study contains convincing but not entirely unexpected evidence that colonic generation of uremic toxins concerns even more molecules than previously demonstrated. GFR is, in many cases, not representative of kidney clearance. The study also supports the concept of molecule families and the existence of a gut/liver/plasma protein binding/kidney tubular axis, the disruption of which by one or more therapeutic measures could bring down the concentration of those solutes. Research in these areas should be able to modify the current paradigm of kidney treatment to make it more sustainable. This includes the exploration of previously underexploited areas such as manipulation of intestinal function, and alternative extracorporeal removal strategies such as adsorption and regenerative medicine. Disclosures R.V. has received travel support and speakers fees from Nikisho and BBraun, and is a consultant for Debiotech, the Dutch Kidney Foundation, and Astra-Zeneca. G.G. reports no conflict.
Summary The topics of Dark Matter and Dark Energy and of the Higgs phenomenon, are amongst the dramatic examples of the universe being to a large extent unknown. Reported in the late 1990âs by S. Perlmutter, B. Schmidt and A. Riess, the Nobel Committee in awarding the Nobel Prize to them in 2011 said: Their âfindings have unveiled a universe that is to a large extent unknown to scienceâ. That is still true today and is likely to be so for decades to come. These findings were based on the behaviour of the Type 1a Supernovae which, due to their consistent brightness, have developed the reputation of being reliable standard candles in cosmological research. Perlmutter, Schmidt and Riess found that these supernovae, as earlier workers for decades had observed, are dimmer than what expected, and they concluded that they must be accelerating faster than believed, in their motion. The work of Riess et al proposed that dark energy, must be a kind of energy that could have an anti-gravitational pull, thus explaining the strange behaviour of the Type 1a supernovae as they move away from us, into the infinite horizon of the universe. Now in the late second decade of the 21st century, no dark energy reality has been discovered at all, and the same applies to the dark matter hypothesis that came out of the work that was awarded the Nobel Prize 2011. It appears like there will perhaps never be any proof of the existence of dark matter and dark energy particles, for these are claimed to be unable to interact with normal matter and energy and not to have any radiation. This is a typical example of why perhaps a Theory of Everything is required to throw some light on the mysterious realities of existence, if possible. Actually explaining something that has no material or energy evidence of any kind, makes that something as impossible to explain as God. They do not interact with anything at all. However, if the Theory of Everything can explain how the universe originated, it might surely also provide evidence of whether dark matter and dark energy exist or not. This appears very tricky for they have been claimed as being totally invisible and insensitive to any kind of experimental set up. 2 The Higgs boson came out dramatically in the work of Higgs, Salam, Weinberg, Glashow and others, that found linkages between the weak force and the electromagnetic force. It is believed in relation to the Higgs boson, even if it is not true, that all particles should have zero mass. Several different eminent physicists thought of rather similar ways of explaining mass and its origin. Generally, it was felt that a new Field that was later called the Higgs Field, permeated the universe, and the property of mass was acquired when particles interacted with this field whose particle was named the Higgs boson, the simplest manifestation of the field. However many physicists believe the Higgs phenomenon and its particle discovered in 2012 should be a more elaborate mechanism, on which further work is ongoing, particularly at the LHC. The feeling is that the phenomenon of mass has not understood in its full reality. It goes without saying that in the absence of a Theory of Everything, it is not possible to really know, as far as possible, the nature and fate of the universe, mainly because the universe was conceived on a deliberate master plan. The implication is that there could have existed only one such specific plan: the supernatural plan to create our universe, which to humans is the Theory of Everything as far as possible, capable to describe our universe. The fact humans are destined to discover the Theory of Everything, according to Kepler and Whewell, indicates there was supernatural creation of the universe, and therefore finding the Theory of Everything is an astounding perspective. The scientific/philosophical Theory of Everything will be describes soon, is coming at a historical juncture where several well-known cosmologists are talking about natural creation from practically nothing or based solely on mathematics. Since most intellectuals and members of the public believe the universe had a supernatural creation, a scientific concept of the origin of the universe by a Supernatural Mind or God, would be of enormous interest. It will be the collision of the traditional imaginary Godless concepts of the origin of our universe with a scientific concept that creates an extraordinary historical event in our current intellectual, scientific, philosophical and theological world. Since the Theory of Everything will be really, as far as possible, a universal and metaphysical concept of the universe, it can produce an intellectual revolution in the scientific and philosophical sectors, that will impact on theology in ways not seen before. There whole world will benefit, for the total 3 confusion that surrounds the comprehension of the realities and origin of our universe would reach a turning point, never seen before. It will demonstrate the power of intellectual knowledge as the torch bearer of humanity. The reason is that intellectual ideas are capable to turn humanity into one collective mind in the universe. The universe under GRT is expanding, and there was never been any tendency for the universe to contract and collapse into an unimaginable black hole. Penroseâs hypothesis of a cosmic crunch and the rebirth of the universe (CCC), is not a possibility, because the uncertainly in science is at the quantum microscale, and not at the macro or universal scale. Gravity was correctly explained by Einstein. He referred to it as pseudo-force, causing the warping of space time, being perhaps a kind of variation of the electromagnetic force. The truth is that the nature of black holes happens to be as misunderstood as is the nature of the universe. Cosmology has been a precariously understood domain, the reason being the lack of adequate cosmological understanding of how the universe came into existence. This is not surprising, as I explain in my coming second book on the origin of the universe, for our world is, historically, at the beginning phase of its modern scientific era, being hardly one century old, if we take the golden age of physics of the first decades of the last century, as marking the beginning of our modern scientific culture. No wonder we do not know the real nature of forces, particles, space, time, atoms, matter, gravitation, expansion of the universe, dark energy, dark matter, and the origin and fate of the universe, topics addressed in my second book due in late 2018. Our extraordinary universe must have been inspired by a scientifically precise and elaborate design. Gravity remains one of the greatest mysteries of science for it has no quantum particulate physical identity, its imagined particle, the graviton cannot exist, and up to now gravity can only be calculated and described, for instance in the equations of Newton and Einstein. It exists because it arises due to totally natural reasons, which were largely seen in Descartesâ belief there must exist a law of the universal conservation of the quantity of motion. The quantum nature of spacetime, if it is not a particle, must have physical realities that are sensitive to acceleration, indicating that spacetime is perhaps fractal in its physical reality or at least mathematically, the reason why Einstein was very precise in his description of general and special relativity. String Theory, a great intellectual exercise, has the weakness of not explaining how exactly the strings acquire their 4 property of vibration. Any Theory of Everything must incontrovertibly explain the origin of motion and of gravitation. The physics of the universe are intimately fused with the philosophy of existence, not surprisingly, as the purpose of creation must have been for producing a conscious being, not solely the universe.
Raziel combines secure multi-party computation and proof-carrying code to provide privacy, correctness and verifiability guarantees for smart contracts on blockchains. Effectively solving DAO and Gyges attacks, this paper describes an implementation and presents examples to demonstrate its practical viability (e.g., private and verifiable crowdfundings and investment funds). Additionally, we show how to use Zero-Knowledge Proofs of Proofs (i.e., Proof-Carrying Code certificates) to prove the validity of smart contracts to third parties before their execution without revealing anything else. Finally, we show how miners could get rewarded for generating pre-processing data for secure multi-party computation.
Debiao He, Yudi Zhang, Ding Wang, KimâKwang Raymond Choo
Mobile device and application (app) security are increasingly important, partly due to the constant and fast-paced cyberthreat evolution. To ensure the security of communication (e.g., data-in-transit), a number of identity-based signature schemes have been designed to facilitate authorization identification and validation of messages. However, in many of these schemes, a user's private key may leak when a new signature is generated since the private keys are stored on the device. Seeking to improve the security of the private key, we propose the first two-party distributed signing protocol for the identity-based signature scheme in the IEEE P1363 standard. This protocol requires that two devices separately store one part of the user's private key, and allows these two devices to generate a valid signature without revealing the entire private key of the user. We formally prove that the security of the protocol in the random oracle model. Then, we implement the protocol using the MIRACL library and evaluate the protocol on two mobile devices. Compared with the protocol of Lindell (CRYPTO'17) that uses the zero-knowledge proof for its security, our protocol is more suitable for deployment in the mobile environment.
Jeremy A. Scher, Michael G. Bayne, Amogh Srihari, Shikha Nangia · 5 authors
The relationship between structure and property is central to chemistry and enables the understanding of chemical phenomena and processes. Need for an efficient conformational sampling of chemical systems arises from the presence of solvents and the existence of non-zero temperatures. However, conformational sampling of structures to compute molecular quantum mechanical properties is computationally expensive because a large number of electronic structure calculations are required. In this work, the development and implementation of the effective stochastic potential (ESP) method is presented to perform efficient conformational sampling of molecules. The overarching goal of this work is to alleviate the computational bottleneck associated with performing a large number of electronic structure calculations required for conformational sampling. We introduce the concept of a deformation potential and demonstrate its existence by the proof-by-construction approach. A statistical description of the fluctuations in the deformation potential due to non-zero temperature was obtained using infinite-order moment expansion of the distribution. The formal mathematical definition of the ESP was derived using the functional minimization approach to match the infinite-order moment expansion for the deformation potential. Practical implementation of the ESP was obtained using the random-matrix theory method. The developed method was applied to two proof-of-concept calculations of the distribution of HOMO-LUMO gaps in water molecules and solvated CdSe clusters at 300 K. The need for large sample size to obtain statistically meaningful results was demonstrated by performing 105 ESP calculations. The results from these prototype calculations demonstrated the efficacy of the ESP method for performing efficient conformational sampling. We envision that the fundamental nature of this work will not only extend our knowledge of chemical systems at non-zero temperatures but also generate new insights for innovative technological applications.
Open access
Advanced Physical and Chemical Molecular Interactions
In order to solve the problem of illegal memberâs tracking attack, which caused by the vehicle unitsâ privacy disclosure in vehicular ad hoc networks (VANETs), a vehicle identity authentication protocol based on lightweight group signature was proposed by analysis of topology and communication characteristics of VANETs in this paper, which can authenticate the vehicles anonymously in a fast and efficient way. The protocol has five stages. In the initialization phase, the public/private key pairs and system parameters of the group were generated by the VANETs system, then the group public key and system parameters were distributed to the on-board units by the roadside auxiliary facilities. The group private key was kept by the group manager. When a vehicle unit entered VANETs, the unitâs own identity was submitted to the group manager by the blind signature. A group certificate would be distributed to the vehicle unit by the group manager when authentication passed. In the cooperative communication stage, the vehicle member who owned the group certificates signed the state information with the valid certificate and group public key, then sent it to the nearby vehicle units by the car sensors, and achieved cooperative driving with surrounding vehicles. In the message verification stage, only can the legal vehicle members open the received status information by using group public key, but couldnât know the true identity of the message sender. In this way, the anonymous communication among vehicles was realized. In the stage of signature verification, when a vehicle unit broadcasted a false message for the purpose of exclusively using road resource and caused traffic accident, the group manager can open the signature of the message by using the group private key, and traversed the corresponding vehicle members to carry on the accountability. The innovation of the paper was the usage of improved lightweight group signature technology, which could ensure that the length of group public key and group signature didnât depend on the number of group members. Zero knowledge proof was also used as a means of membership authentication which improved the speed of authentication among the members. The security of the protocol was analyzed and proved mathematically in this paper, and a LAN simulation platform composed of 100 PC machines was built to simulate the cooperative communication among vehicle units in VANETs. The experimental results showed that authentication time of the protocol was about 7 ms among 100 vehicle users. The performance of the proposed protocol is superior to the contrasted schemes. It greatly reduced the storage and calculation burden of the vehicle units during the process of identity authentication.
BITCONCH chain proposed an innovative POR (Proof Of Reputation) reputation consensus algorithm, which solved the pain point that the blockchain is difficult to maintain both high throughput and decentralization. Based on social graphs, BITCONCH Chain mathematically models social, time, and contribution activities to build a decentralized reputation system. Each user has the opportunity to establish a high reputation value. The higher the user's reputation, the lower the transaction cost (or even free). The more opportunities that are selected as trust nodes to participate in the consensus, the greater the benefits. High-reputation users are defined as âmutual trust nodesâ, and small micro-transactions will start âpayment channelsâ for high-speed offline transactions. The reputation system and system incentive system will effectively promote the continued enthusiasm of business developers and ordinary users, and contribute to the construction of the business ecosystem. Business developers with traffic are more likely to get high reputation values, and the chances of being elected to a trusted full node are higher. Ordinary users can increase reputation by actively engaging in social interactions and actively using business applications in the ecosystem, increasing the chances of being selected as trusted light nodes. The Bitconch chain uses a DAG directed acyclic graph data structure to maintain the system's positive scalability. Support smartphone light node client to resist the decentralization of the system and maintain dispersion. Zero-knowledge verification, latticed data storage, quantum-level encryption algorithms, and improved BVM virtual machines make Bitconch chain more reliable and provide a friendly DApp and sidechain development environment to meet certain applications. Technical requirements for large file storage, low transaction costs, user information protection, sidechain and smart contract iterations, and bug fixes. BITCONCH chain is a decentralized distributed network with no block and no chain, which solves two difficulties in the application of blockchain: scalability and decentralization. Bitconch chain, which can be applied to the commercial application needs of users above 10 million, is the most feasible blockchain ecosystem for high-frequency small micro-transactions and social applications.
This paper describes the development of a multiagent system (MAS) to support the implementation of zero-defect manufacturing strategies in multi-stage production systems. The MAS infrastructure, combined with on-line inspection tools, data analytics and knowledge generation, constitutes a suitable approach to integrate process and quality control in multi-stage environments. This will allow the early detection of product defects, the adaptation to operating condition changes and the optimisation of manufacturing processes. This type of integrated management structure is aligned with a zero-defect manufacturing production model which is of paramount importance in the actual state-of-the-art manufacturing paradigms. As a proof of concept, the devised manufacturing supervision model was deployed into an experimental multi-stage system that run a set of several tests on electrical motors. The agent-based solution was implemented using the JADE framework and the exchange of information structured by proper data models and industrial based Internet-of-Things and Machine-to-Machine technologies, such as OPC-UA, REST and JSON. The obtained results demonstrate the suitability of the devised integrated management model as a vehicle to achieve dynamic and continuous system improvement in multi-stage manufacturing environments.
Jul 1, 2018·2018 IEEE International Conference on Internet of Things (iThings) and IEEE Green Computing and Communications (GreenCom) and IEEE Cyber, Physical and Social Computing (CPSCom) and IEEE Smart Data (SmartData)
Scalability and privacy are two challenges for today's blockchain systems. Processing transactions at every node in the system limits the system's ability to scale. Furthermore, the requirement to publish all corporate or individual information for processing at every node, essentially making the data public, is - despite of all other advantages - often considered a major obstacle to blockchain adoption. In this paper, we make two main contributions to address these two problems: (i) To increase efficiency, we propose a processing model which employs non-interactive proofs to off-chain computations, thereby reducing on-chain computational efforts to the verification of correctness of execution rather than the execution itself. Due to the verifiable computation scheme's zero-knowledge property, private information used in the off-chain computation does not have to become public to verify correctness. (ii) We introduce ZoKrates, a toolbox to specify, integrate and deploy such off-chain computations. It consists of a domain-specific language, a compiler, and generators for proofs and verification Smart Contracts. ZoKrates hides significant complexity inherent to zero-knowledge proofs, provides a more familiar and higher level of programming abstractions to developers and enables circuit integration, hence fostering adoption.
Scanning of museum specimens has taken off. Using 3-D computed tomography (CT), specimens are scanned and, along with underlying digital data, are stored in online repositories, such as Digimorph, MorphoSource, iDigBio, and others. The material is made publicly available. But a host of legal questions have emerged, including ownership of scans, data, and the ability (or lack thereof) to copyright them. Do the people in possession of the specimen own it, and do they have permission to distribute the specimen for scanning? Who claims the rights to the digital data? Does a contract between the owning institution and the source of the specimen affect its digital reproduction and distribution? Tim White, director of collections and research, Yale Peabody Museum of Natural History, notes: ââŠresearchers will borrow something and then realize [they] want to have these specimens scannedâŠoften at a third-party institution and the museum may only find out after the fact.â Does Yale own the specimen or is it on loan? Is there shared ownership by a written agreement? Who scanned the specimenâthe borrowing institution or another organization that owns scanning equipment? According to David Bloom of VertNet, a National Science Foundation funded project, the loaning institution owns or manages the specimen, although the scan belongs to the borrower. Intellectual property attorney and former museum curator Amanda Nelson warns that it is not so simple. In the Yale example, much depends on the paperwork between the loaner and borrower. To avoid misunderstandings, Dirk Neumann of the Bavarian Natural History Collection, suggests the owner add âa specific section on the loan form that the borrower cannot get copyright ownership in his imaging but may use the images for his research purpose, so that there is a written proof of the borrower that he is author of the images but waives his copyright.â Doug Boyer, of Duke University and founder of the MorphoSource 3-D data and imagery repository, explains that museums have release forms that state what can be done with the specimen and may include a third-party clause that limits rights to distribute the data. In the United States, unlike in most European countries, medical scans cannot be copyrighted, as the copyright office does not judge them to have creative input. But Boyer suggests organizations assert copyright for their 3-D scans, many of which are derivative, posted in online repositories. Prepping and scanning a specimen for research involves value judgments and creativity to emphasize certain parts of its anatomy. Boyer thinks copyright should be applicable to research scans: âThere's no question that at least the derivative images are copyrightable.â As attorney Nelson notes, âThe bar for creativity has been set so low, sometimes just merely changing [or adding] colorsâŠis a creative choice.â Patent attorney Sarita Pickett, of Mesmer & Deleault, explains that technology has changed so quickly âthe laws have not always had time to catch upâŠ.â Copyright âclerks are unlikely to have the experience necessary to recognize when additional design elements are involved in activities that were previously entirely technological,â says Pickett. Part of the problem is how scientists describe their scans. Scientists put creative thought into designing and coloring a scan, âbut when they describe what they did, they donât use creative terms, leaning too heavily on the functionality aspect [showing frog bones]âas might be appreciated by another scientist.â To Boyer's knowledge, no scientists have registered copyright of their CT scans, but the MorphoSource group encourages researchers to assert copyright and ownership of their scans. The copyright issue will likely be determined in the courts, he added. A network of US-based museums and working groups is devising best practices and guidelines for archiving and sharing 3D data, and Boyer is optimistic that this will help museums share their collections globally. Data, too, are an issue. Nelson says, generally âdata canât be copyrighted.â Identifying tags on a specimen âcannot be copyrighted because that's information; that's fact.â The basis for this policy is that sharing the data is âfor the benefit of society [as] a wholeâ for research and study. Some institutions want to maintain the open availability of data, although others want to limit what can be done with the data. The Creative Commons licensing mechanism can leave data or scans open to all, limit use, or claim copyright worldwide. Most data put online are for noncommercial use. But, warns Nelson Rios of Yale Peabody, âThere's absolutely zero enforcement behind any of thatâŠit's too complicated to pursue; also it's too expensive.â No matter what, Amanda Nelson points to the value of paperwork: âAt the end of the day, it's who signed what and what does it say.â Myrna E. Watanabe (mewatanabeconsulting@gmail.com) is a science and grant writer in Patterson, New York.