We study the relationship between problems solvable by quantum algorithms in polynomial time and those for which zero-knowledge proofs exist. In prior work, Aaronson [arxiv:quant-ph/0111102] showed an oracle separation between BQP and SZK, i.e. an oracle $A$ such that $\mathrm{SZK}^A \not\subseteq \mathrm{BQP}^A$. In this paper we give a simple extension of Aaronson's result to non-interactive zero-knowledge proofs with perfect security. This class, NIPZK, is the most restrictive zero-knowledge class. We show that even for this class we can construct an $A$ with $\mathrm{NIPZK}^A \not\subseteq \mathrm{BQP}^A$.
We study the relationship between problems solvable by quantum algorithms in\npolynomial time and those for which zero-knowledge proofs exist. In prior work,\nAaronson [arxiv:quant-ph/0111102] showed an oracle separation between BQP and\nSZK, i.e. an oracle $A$ such that $\\mathrm{SZK}^A \\not\\subseteq\n\\mathrm{BQP}^A$. In this paper we give a simple extension of Aaronson's result\nto non-interactive zero-knowledge proofs with perfect security. This class,\nNIPZK, is the most restrictive zero-knowledge class. We show that even for this\nclass we can construct an $A$ with $\\mathrm{NIPZK}^A \\not\\subseteq\n\\mathrm{BQP}^A$.\n
In this paper, we have achieved privacy protection and high transparency in a permissioned blockchain. There is a sidechain that connects the permissionless blockchain and the permissioned blockchain. The behavior in the permissioned blockchain is almost a black box from the perspective of the permissionless blockchain. While this fact is useful for privacy protection, there is room for improvement in terms of transparency. To improve the transparency of the permissioned blockchain under privacy protection, we consider traceability in the permissioned blockchain consisting of the following three properties: trade privacy (who trades with whom and at what asset amount), preservation (the total amount inside the permissioned blockchain, including deposits and withdrawals to the permissionless blockchain, is immutable), and noninvolvement (some members in the permissioned blockchain are not involved in some trades, and it is possible to prove that specified members performed the transaction). To the best of our knowledge, we are the first to achieve both preservation and noninvolvement while protecting the privacy of transactions. Our approach is as follows. We model traceability based on the hidden Markov model. Because the proof of traceability requires the calculation of more than quadratic degrees, we encrypt this model by homomorphic encryption. The number of participants in the permissioned blockchain corresponds to the number of additions in the model. Then, we can construct the encrypted model by employing somewhat homomorphic encryption. The establishment of the original model is verifiable by applying the noninteractive zero-knowledge proof of the knowledge that the plaintext is equal to zero. This is an adaptation of Benhamouda et al. (Asiacrypt 2014).
Block chain technology, while revolutionizing various sectors, faces significant challenges regarding data privacy and security. As block chain networks become more widespread, the need for privacy-preserving techniques becomes critical to ensure the confidentiality, integrity, and anonymity of user data. This article reviews various privacy-enhancing techniques implemented in block chain networks, including cryptographic protocols, zero-knowledge proofs, and off-chain solutions. The aim is to identify their effectiveness, limitations, and the trade-offs between privacy and performance. Through a comprehensive analysis, this study explores existing methodologies and suggests potential improvements for safeguarding privacy while maintaining the decentralized and transparent nature of block chain systems.
Ride-sharing is a service that enables drivers to share trips with other riders, contributing to appealing benefits of shared travel cost and reducing traffic congestion. However, the majority of existing ride-sharing services rely on a central third party to organize the service, which make them subject to a single point of failure and privacy disclosure concerns by both internal and external attackers. Moreover, they are vulnerable to distributed denial of service (DDoS) and Sybil attacks launched by malicious users and external attackers. Besides, high service fees are paid to the ride-sharing service provider. In this paper, we propose a decentralized ride-sharing service based on public Blockchain, named B-Ride. B-Ride enables drivers to offer ride-sharing services without relying on a trusted third party. Both riders and drivers can learn whether they can share rides while preserving their trip data, including pick-up/drop-off location, departure/arrival date and travel price. However, malicious users exploit the anonymity provided by the public blockchain to submit multiple ride requests or offers, while not committing to any of them, in order to find a better offer or to make the system unreliable. B-Ride solves this problem by introducing a time-locked deposit protocol for a ride-sharing by leveraging smart contract and zero-knowledge set membership proof. In a nutshell, both a driver and a rider have to show their good will and commitment by sending a deposit to the blockchain. Later, a driver has to prove to the blockchain on the agreed pick-up time that he/she arrived at the pick-up location on time. To preserve rider/driver privacy by hiding the exact pick-up location, the proof is performed using zero-knowledge set membership proof. Moreover, to ensure fair payment, a pay-as-you-drive methodology is introduced based on the elapsed distance of the driver and rider. In addition, we introduce a reputation model to rate drivers based on their past behaviour without involving any third-parties to allow riders to select them based on their history on the system. Finally, we implement our protocol and deploy it in a test net of Ethereum. The experimental results show the applicability of our protocol atop existing real-world blockchains.
Ride-sharing is a service that enables drivers to share their trips with\nother riders, contributing to appealing benefits of shared travel costs.\nHowever, the majority of existing platforms rely on a central third party,\nwhich make them subject to a single point of failure and privacy disclosure\nissues. Moreover, they are vulnerable to DDoS and Sybil attacks due to\nmalicious users involvement. Besides, high fees should be paid to the service\nprovider. In this paper, we propose a decentralized ride-sharing service based\non public Blockchain, named B-Ride. Both riders and drivers can find rides\nmatch while preserving their trip data, including pick-up/drop-off location,\nand departure/arrival date. However, under the anonymity of the public\nblockchain, a malicious user may submit multiple ride requests or offers, while\nnot committing to any of them, to discover better offer or to make the system\nunreliable. B-Ride solves this problem by introducing a time-locked deposit\nprotocol for a ride-sharing by leveraging smart contract and zero-knowledge set\nmembership proof. In a nutshell, both a driver and a rider have to show their\ncommitment by sending a deposit to the blockchain. Later, a driver has to prove\nto the blockchain on the agreed departure time that he has arrived at the\npick-up location. To preserve rider/driver location privacy by hiding the exact\npick-up location, the proof is done using zero-knowledge set membership\nprotocol. Moreover, to ensure a fair payment, a pay-as-you-drive methodology is\nintroduced based on the elapsed distance of the driver and the rider. Also, we\nintroduce a reputation-based trust model to rate drivers based on their past\ntrips to allow riders to select them based on their history on the system.\nFinally, we implement B-Ride in a test net of Ethereum. The experiment results\nshow the applicability of our protocol atop the existing real-world blockchain.\n
With the growth in popularity for cryptocurrencies the need for privacy preserving blockchains is growing as well. Zcash is such a blockchain, providing transaction privacy through zero-knowledge proofs. In this paper we analyze transaction linkability in Zcash based on the currency minting transactions (mining). Using predictable usage patterns and clustering heuristics on mining transactions an attacker can link to publicly visible addresses over 84% of the volume of the transactions that use a ZK-proof. Since majority of Zcash transactions are not yet using ZK-proofs, we show that overall 95.5% of the total number of Zcash transactions are potentially linkable to public addresses by just observing the mining activity.
A thermally activated absorption heat pump suitable for use in naval expeditionary Environmental Control Units, as well as residential space-conditioning, is developed. Waste heat characteristic of the exhaust stream from a diesel engine GenSet is used to drive an absorption cycle to provide cooling. The heat source is coupled to the heat pump using an intermediate fluid loop for flexible deployment. With minor modifications, the heat pump could also provide heating at high coefficients of performance, resulting in versatile functionality. This technology capitalizes on heat and mass transfer enhancement possible in microscale passages to provide a compact architecture for the components and the overall system. The working fluid pair with zero Global Warming Potential is contained within this assembly, reducing fluid inventories significantly over conventional systems. Quiet, reliable, long-life operation due to the absence of a compressor and the use of few moving parts are further critical distinguishing advantages. Modularity in cooling capacity has been demonstrated through scaling-up of component geometry and internal features and dimensions. The core technology was initially demonstrated with a proof-of-concept microscale absorption chiller measuring 200 × 200 × 34 mm and weighing 7 kg that delivered 300 W of cooling in laboratory tests. In the previous BEETIT project, the team made significant advances over the proof-of-concept. System and component designs with > 10× scale-up in capacity were developed, in a packaged unit capable of standalone operation with a semi-autonomous control system. A cooling capacity of 3.5 kW with a COP > 0.5 at an ambient temperature of 35°C was demonstrated for this natural gas-fired unit. Significant cost reductions in fabrication were achieved using low-cost brazing instead of diffusion bonding. In companion projects funded by the Southern Company and the Georgia Research Alliance, stamping and fluid forming techniques were investigated to fabricate microscale features instead of photochemical etching, thereby leading to significant cost reductions. In a follow-on effort funded by ARPA-E and NAVFAC, a 2.7 kW cooling unit was developed to provide cooling at a severe ambient condition of 51.7°C. The unit was driven directly by diesel engine exhaust heat. Innovative finned heat and mass exchangers for the ambient-coupled condenser and absorber were developed. In the present effort, a standalone, packaged and controllable 10.5 kW cooling capacity absorption chiller is developed. This demonstrates a 30× scale up from the proof-of-concept, thus validating the scalability of microchannel heat exchangers for absorption heat pumps. Autonomous operation algorithms demonstrated enhanced dynamic performance. The knowledge from previous projects was leveraged to develop novel component designs that further helped in miniaturizing the heat exchangers. All coupling fluids are hydronically coupled to aid flexible field deployment. The prototype unit provides design cooling capacity at high ambient temperature conditions of 44°C at COP > 0.6.
Open access
Advanced Thermodynamic Systems and Engines
Refrigeration and Air Conditioning Technologies
Thermodynamic and Exergetic Analyses of Power and Cooling Systems
A zero-knowledge proof is a fundamental cryptographic primitive that enables the verification of statements without revealing unnecessary information. Zero-knowledge proofs are a key component of many cryptographic protocols and, often, one of their main efficiency bottlenecks. In recent years there have been great advances in improving the efficiency of zero-knowledge proofs, bring them closer to wide deployability. In this thesis we make another step towards the construction of computationally-efficient zero-knowledge proofs. Specifically, we construct efficient zero-knowledge proofs for the satisfiability of arithmetic circuits for which the computational cost of the prover is only a constant factor more expensive than direct evaluation of the circuit. We also construct efficient zero-knowledge proofs to check the correct execution of (Tiny)RAM programs. In this case the computational cost for the prover is a superconstant factor larger than executing the program directly. Our proofs also support efficient verification and small proof sizes. For security, they rely on symmetric primitives and could potentially withstand attacks from quantum computers. On a different research direction, we look at group signatures, a fundamental primitive which relies on zero-knowledge proofs. A group signature enables users to sign anonymously on behalf of a group of users. In case of dispute a Manager can identify the author of a signature and potentially banish the user from the group. In this thesis we address the fundamental question of defining the security of fully dynamic group signatures, for which the users can join and leave at any time. Differently from other restricted settings, this case has been largely overlooked in the past. Our security model is general, does not implicitly assume existing design paradigms and captures the security of existing models for more restricted settings.
In this work we consider the interplay between multiprover interactive proofs, quantum entanglement, and zero knowledge proofs - notions that are central pillars of complexity theory, quantum information and cryptography. In particular, we study the relationship between the complexity class MIP*, the set of languages decidable by multiprover interactive proofs with quantumly entangled provers, and the class PZK-MIP*, which is the set of languages decidable by MIP* protocols that furthermore possess the perfect zero knowledge property. Our main result is that the two classes are equal, i.e., MIP* = PZK-MIP*. This result provides a quantum analogue of the celebrated result of Ben-Or, Goldwasser, Kilian, and Wigderson (STOC 1988) who show that MIP = PZK-MIP (in other words, all classical multiprover interactive protocols can be made zero knowledge). We prove our result by showing that every MIP* protocol can be efficiently transformed into an equivalent zero knowledge MIP* protocol in a manner that preserves the completeness-soundness gap. Combining our transformation with previous results, we obtain the corollaries that i) all languages that can be solved in non-deterministic double exponential time have zero knowledge MIP* protocols and ii) all co-recursively enumerable languages (which include undecidable problems as well as all decidable problems) have zero knowledge MIP* protocols with vanishing promise gap.
Zero-Knowledge Proof-of-Identity from trusted public certificates (e.g.,\nnational identity cards and/or ePassports; eSIM) is introduced here to\npermissionless blockchains in order to remove the inefficiencies of\nSybil-resistant mechanisms such as Proof-of-Work (i.e., high energy and\nenvironmental costs) and Proof-of-Stake (i.e., capital hoarding and lower\ntransaction volume). The proposed solution effectively limits the number of\nmining nodes a single individual would be able to run while keeping membership\nopen to everyone, circumventing the impossibility of full decentralization and\nthe blockchain scalability trilemma when instantiated on a blockchain with a\nconsensus protocol based on the cryptographic random selection of nodes.\nResistance to collusion is also considered.\n Solving one of the most pressing problems in blockchains, a zk-PoI\ncryptocurrency is proved to have the following advantageous properties:\n - an incentive-compatible protocol for the issuing of cryptocurrency rewards\nbased on a unique Nash equilibrium\n - strict domination of mining over all other PoW/PoS cryptocurrencies, thus\nthe zk-PoI cryptocurrency becoming the preferred choice by miners is proved to\nbe a Nash equilibrium and the Evolutionarily Stable Strategy\n - PoW/PoS cryptocurrencies are condemned to pay the Price of Crypto-Anarchy,\nredeemed by the optimal efficiency of zk-PoI as it implements the social\noptimum\n - the circulation of a zk-PoI cryptocurrency Pareto dominates other PoW/PoS\ncryptocurrencies\n - the network effects arising from the social networks inherent to national\nidentity cards and ePassports dominate PoW/PoS cryptocurrencies\n - the lower costs of its infrastructure imply the existence of a unique\nequilibrium where it dominates other forms of payment\n
As Electric Vehicles (EVs) are becoming widely available, their secure management is crucial to fully enable their potential. For instance, for convenient charging, they may require quick authentication with the charging stations while they are on the go. As charging is frequently needed, exposing one's charging frequency to the stations may risk the exposure of privacy for the EV driver. Therefore, a mechanism is needed to hide EV information. In this paper, we propose using zero-knowledge proofs to achieve this goal. While zero-knowledge proofs can provide anonymous authentication, they require computation for generation of witnesses. Therefore, we assess the overhead of generating a witness and proof computation at the resource constrained on-board units (OBUs) which are deployed on EVs that utilize wireless communications for scheduling. The results indicate that computation overhead is minimal and can be delployed on resource contrained devices.
User's digital identity information has privacy and security requirements. Privacy requirements include confidentiality of the identity information itself, anonymity of those who verify and consume a user's identity information and unlinkability of online transactions which involve a user's identity. Security requirements include correctness, ownership assurance and prevention of counterfeits of a user's identity information. Such privacy and security requirements, although conflicting, are critical for identity management systems enabling the exchange of users' identity information between different parties during the execution of online transactions. Addressing all such requirements, without a centralized party managing the identity exchange transactions, raises several challenges. This paper presents a decentralized protocol for privacy preserving exchange of users' identity information addressing such challenges. The proposed protocol leverages advances in blockchain and zero knowledge proof technologies, as the main building blocks. We provide prototype implementations of the main building blocks of the protocol and assess its performance and security.
The notion of risk plays a central role in economics, finance, health, psychology, law and elsewhere, and is prevalent in managing challenges and resources in day-to-day life. In recent work, Duncan Pritchard (2015, 2016) has argued against the orthodox probabilistic conception of risk on which the risk of a hypothetical scenario is determined by how probable it is, and in favour of a modal conception on which the risk of a hypothetical scenario is determined by how modally close it is. In this article, we use Pritchard's discussion as a springboard for a more wide-ranging discussion of the notion of risk. We introduce three different conceptions of risk: the standard probabilistic conception, Pritchard's modal conception, and a normalcy conception that is new (though it has some precursors in the psychological literature on risk perception). Ultimately, we argue that the modal conception is ill-suited to the roles that a notion of risk is required to play and explore the prospects for a form of pluralism about risk, embracing both the probabilistic and the normalcy conceptions. We take the view that a risk judgment always implicates a body of evidence, which we refer to as the background evidence. In cases where the background evidence is not made explicit, we take it to be supplied by the context of utterance and, in typical cases, to be the evidence possessed by the one making the judgment. That is, we are inclined towards a contextualist semantics for utterances such as 3 and 4, on which their truth conditions feature an evidence parameter, the value of which is fixed by the context. The semantics of such utterances is not, however, our primary concern here. As well as making categorical risk judgments such as the above, we often make comparisons. While we may judge that the risk of a plane crash is very low, we may also judge that there is a higher risk of a car crash on the way to the airport. As well as judging that there's a high risk of food poisoning at a particular restaurant, we might also judge that there is a lower risk of food poisoning at the restaurant next door. Moreover, while we often speak about the riskiness of feared events, such as plane crashes, food poisoning, etc., we can also assess the risk of states of affairs. For instance, before drilling into the wall of a 1970s West Australian house, one might assess the risk that the wall contains asbestos, or jurors in a criminal trial, when contemplating a guilty verdict, might consider the risk that the defendant is innocent, or a mountaineer may ponder the risk that the snow conditions are unfavourable for a climb. Here, we treat propositions as the primary bearers of risk, with the riskiness of an event or state of affairs corresponding to the riskiness of the proposition that the event occurs, or the state of affairs obtains. As well as making judgments about the risk of specific events and states of affairs, people also assess the risk of activities or decisions, saying things like ‘Drilling into this wall is risky’, ‘It would be risky to attempt a climb under these conditions’. These judgments are important to understanding the connections between risk and decision making but we put them to one side here. According to the probabilistic of risk, the risk of a proposition is determined by the of higher the the higher the risk. this the risk of is higher the risk of in is more probable is. The be as the background evidence. 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As a on the modal of risk and very different The in which the in are to the in which the in the risk of the is higher in the the in both While Pritchard make this it is to that the modal in which is is a in which is or a in which As the in which is be the in which is or the in which is or a of the that a The in which a or a be more the in which a and more the in which a in which a or a be a in which a or a in which a the modal the risk of be higher the risk of and the risk of in be to the higher of these on the modal the risk of is and the risk of is low, it that the risk of is as required by it has a of the modal of risk a which as to it can play one of the roles that we a notion of risk. we can is that as more to the it is to on the modal event which be at high risk of and state of affairs which be at high risk of put the is it that be is to is but be is there is a which is in which to the modal there is a risk of we can to a concern about the modal notion of risk. one is about to into a wall in a West Australian in the and is about the risk that the wall contains the modal the wall asbestos, the risk is In this there is a which the wall contains on the the wall not asbestos, to the modal the risk be in which this is be of the In on the modal it that one make a judgment about the risk that the wall contains a view as to it consider the of jurors in a criminal are contemplating a guilty and about the risk that the defendant is the to the to the defendant as the is the risk that the defendant is not the the the defendant the and the are and the modal that the risk is In this the in which the defendant is be very the of the be different in these but the be or on the the defendant is in innocent, and the are or In this on the modal the risk that the defendant is the is in this the in which the defendant is is the on the modal it that one assess the risk that the defendant is a on is or is the risk is and is the risk is to be of when it to making a decision discussion this also Pritchard's about the about these it for that the conditions in are not that the in the the by at and the in the the by at and the to speak a of next we in a in which the conditions in are the modal would that the risk in is at as high as the risk in or of the modal that there are some cases in which one can judge a proposition to be high risk the to take a view on is In for instance, the modal to judge that there is a high risk be the while on be the of these in the we that there is a very in which While this be it the that the modal is one judge that there is a risk of that is is one on the modal be in an in which it is to judge that there is a risk of That is, a of the modal the wall or the defendant is innocent, one judge these propositions to be risk. however, on the modal these judgments be this is in to the probabilistic the probabilistic the risk that the wall contains or the risk that the defendant is innocent, is a of the evidence, and not on the wall contains asbestos, or the defendant is while the is on the modal can with this in a we there is an notion of risk that can some of the of the modal this particular a one we can consider is how probable it is that the proposition is we might consider is how or it would be for that proposition to be As the discussion our to the is not determined by our to the We might judge that the more in the of an are that we might consider is how or it would be for a proposition to be is to judge that it would be more for the to in in the are it might be for a particular of in the next there is a in which there would be about this some of has to and it may as well be this as In it would be for the in the to the by at and the in the to the by at and the to to speak a of next is this notion of normalcy which is to when we an event as we that it is or In this of it would as for to be the that in the would as when we a as we are not making a about the in to or car to when in the and not not that this is of is that there to be some specific for is there's a with the or the in house, the car is or has the there has to be more to the this is we in these events as may be for to be the that in the but this a of the are on an the to that the conditions in the by at the in the the by at and the to speak a of next are events that would As well as with to how we may also with to how with the normalcy of a proposition to the normalcy of the in which it is the in which the be in which of that an in In the in which the conditions of are are According to the of risk, the risk of a proposition is determined by the normalcy of the in which is more these the higher the risk. this the risk of is higher the risk of in the in which is are more the in which is this be to in which the background evidence and which are with the background evidence. 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A phishing attack is one of the severe threats to the smartphone users. As per the recent lookout report, mobile phishing attack is increasing 85% year to year and going to become a significant threat to the smartphone users. This social engineering attack attempts to get the user’s password by disguising as trusted service provider. Most of the smartphone users are using the Internet services outside of the traditional firewall. Cloud-based documents are one of the primary targets of this phishing attack in mobile cloud computing. Also, most smartphone users are using the cloud storage in their device. To secure against this password attack in a mobile cloud environment, we propose a new authentication scheme to provide novel security to the mobile cloud services. This scheme will verify the user and service provider without transmitting the password using the Zero-knowledge proof based authentication protocol. Moreover, the proposed scheme will provide mutual authentication between the communication entities. The effectiveness of proposed scheme would be verified using protocol verification tool called Scyther.
Liang Wang, Gilad Asharov, Rafael Pass, Thomas Ristenpart · 5 authors
We explore how to build a blind certificate authority (CA). Unlike conventional CAs, which learn the exact identity of those registering a public key, a blind CA can simultaneously validate an identity and provide a certificate binding a public key to it, without ever learning the identity. Blind CAs would therefore allow bootstrapping truly anonymous systems in which no party ever learns who participates. In this work we focus on constructing blind CAs that can bind an email address to a public key. To do so, we first introduce secure channel injection (SCI) protocols. These allow one party (in our setting, the blind CA) to insert a private message into another party's encrypted communications. We construct an efficient SCI protocol for communications delivered over TLS, and use it to realize anonymous proofs of account ownership for SMTP servers. Combined with a zero-knowledge certificate signing protocol, we build the first blind CA that allows Alice to obtain a X.509 certificate binding her email address alice@domain.com to a public key of her choosing without ever revealing ``alice'' to the CA. We show experimentally that our system works with standard email server implementations as well as Gmail.
The development of quantum computers has urged the cryptographic community to prepare cryptographic primitives for the eventual arrival of the post‐quantum world. To this end, the authors study the witness indistinguishability (WI) and witness hiding (WH) of proof systems against quantum adversaries. They give formal definitions of quantum WI (QWI) and quantum WH (QWH), present proof systems satisfying these definitions, and specify a condition under which QWI implies QWH. Regarding the non‐interactive proof systems, they prove that, even if a common reference string is used to generate polynomially many non‐interactive proofs, the QWI is still preserved, while quantum zero‐knowledge has no such beneficial property. To show the strength of QWI, they present two applications of them. First, they prove that the construction proposed by Feige et al . that transforms any non‐interactive bounded zero‐knowledge proof system to a general one is also feasible against quantum adversaries. Second, they construct a quantum‐secure signature scheme in the CRS model, which is existentially unforgeable against quantum adversaries and remains secure even if a common random string is used to sign polynomially many messages.
The Internet of Things (IoT) is very attractive because of its promises. However, it brings many challenges, mainly issues about privacy preservation and lightweight cryptography. Many schemes have been designed so far but none of them simultaneously takes into account these aspects. In this paper, we propose an efficient attribute-based credential scheme for IoT devices. We use elliptic curve cryptography without pairing, blind signing, and zero-knowledge proof. Our scheme supports block signing, selective disclosure, and randomization. It provides data minimization and transaction unlinkability. Our construction is efficient since smaller key size can be used, and computing time can be reduced. As a result, it is a suitable solution for IoT devices characterized by three major constraints, namely low-energy power, small storage capacity, and low computing power.
Abrar O. Alkhamisi and Fathy Alboraei Abrar O. Alkhamisi and Fathy Alboraei
In recent years, the Internet of Things (IoT) plays a vital role in our daily activities .Owing to the increased number of vulnerabilities on the IoT devices, security becomes critical in the untrustworthy IoT environment. Access control is one of the top security concerns, however, implementing the traditional access control mechanisms in the resource-constrained nature of the IoT devices is a challenging task. With the emergence of blockchain technology, several recent research works have focused on the adoption of blockchain in IoT to resolve the security concerns. Despite, integrating the blockchain in the resource-constrained IoT context is difficult. To overcome these obstacles, the proposed work presents a privacy-aware IoT security architecture to ensure the access control based on Smart contract for resource-constrained and distributed IoT devices. The design of the proposed architecture incorporates three main components such as the contextual blockchain gateway, decentralized revocation manager, and non-interactive zero-knowledge proof based validation. By modeling the contextual blockchain gateway, the proposed architecture ensures the dynamic authentication and authorization based on the contextual information and access policies. Instead of integrating the blockchain technology into resource-constrained IoT devices, the smart contract-based distributed access control system with the contextual blockchain gateway provides the scalable solution. With the association of decentralized revocation manager in the smart contract, it prevents the resource access from the unauthorized users by dynamically generating and updating the revoked user list of all the nodes in the smart contract. Moreover, the proposed architecture employs the non-interactive zeroknowledge proof cryptographic protocol to ensure the transaction privacy within the smart contract. Consequently, it maintains the trade-off between the transparency and privacy while ensuring the security for the distributed IoT environment.
The atmosphere at the 5th Annual Immuno-Oncology 360° (IO360°) Conference, which took place on February 6–8 at the Crowne Plaza Times Square in New York City, was truly collaborative. Co-chaired by Axel Hoos, MD, PhD (GSK), James Gulley, MD, PhD (National Cancer Institute [NCI]), and Andrew Baum, MD (Citi), the conference featured almost 100 speakers and 10 plenary sessions, including 4 keynote talks and 7 panel discussions. More than 400 attendees representing the pharma, biotech, academic, regulatory, and private investment communities gathered to discuss the rapid advancement in scientific, clinical, and business developments in IO, with the goal of accelerating the development of new therapeutics for patients. Over 350 partnering meetings took place over the 3-day conference.“360 degrees means we really want to speak to all stakeholders,” stated Dr. Hoos. The meeting is structured for the scientists to bring their most promising next-generation mechanisms that will help address these challenges. However, it is also important to look at therapies that haven't worked, so we don't repeat the same challenges of the past, he noted. “But IO360° is not just the science, it's about the entire ecosystem in which the science exists, and that includes the patients and those that provide the funding to make the science happen.”Michel Sadelain, MD, PhD, of Memorial Sloan Kettering Cancer Center, opened the meeting with a keynote, Chimeric Antigen Receptor (CAR) - T Cell Therapy and the CD19 Paradigm. With two CD19 CAR-T cells (CAR Ts) approved in 2017, Dr. Sadelain identified three new directions being taken to optimize CAR T therapy and develop next-generation CAR Ts. The first is addressing exhaustion (loss of functionality) using genome engineering at a carefully select locus (TRAC) to create more potent CAR Ts and incorporating new designs that modify the activating portion of the CAR and balance rapid expansion and retained memory (1XX CAR). The second is gaining insight into the pathophysiology of cytokine release syndrome, including CAR T–macrophage interactions, to try and reduce toxicity. The third is employing new strategies for circumventing antigen escape, such as use of radiosensitization and combinatorial targeting.The Discovery and Preclinical Science plenary focused on strategies being investigated to modify the tumor microenvironment and address limitations of patient-sourced therapies. According to the plenary chair, Ronald Herbst, PhD, “we are all excited about the potential for immunotherapy for patients with cancer, but many patients don't respond to checkpoint inhibitors.” Part of the problem is explained by the fact that “immune contexture varies within and across tumor types, and so-called ‘hot’ versus ‘cold’ tumors,” he noted. In order to increase the efficacy of immunotherapy, a number of areas are actively being targeted, including antigen presentation, innate mechanisms of activation, the tumor microenvironment, and overcoming immunosuppression.A variety of cells, growth factors, and cytokines in the tumor microenvironment play a pivotal role in whether or not immunotherapy is effective. Various strategies are being employed that attempt to modify the tumor microenvironment to overcome immunosuppressive mechanisms, such as blocking adenosine with an anti-CD73 monoclonal antibody (oleclumab, Medimmune) or an A2A receptor antagonist (CPI-144, Corvus), or inhibiting the IDO (indoleamine 2,3-dioxygenase) pathway (indoximod, NewLink Genetics). Other strategies are being employed to enhance the efficacy of cytokines to augment the expansion and activation of T cells, such as engineering enhanced versions of growth factors such as interleukin-2 (IL-2; NKTR-214, Nektar, and MDNA109, Medicenna) and IL-10 (pegilodecakin, ARMO). For example, pegilodecakin, a long-acting pegylated form of IL-10, induces hallmarks of CD8+ T cell immunity in cancer patients. According to Aung Naing, MD, and Martin Oft, MD, pegilodecakin demonstrated clinical benefit in studies as a single agent and in combination with both chemotherapy and checkpoint inhibitors across several tumor types. The agent is currently being investigated in a Phase 3 trial in metastatic pancreatic cancer.Off-the-shelf hematopoietic cell products are being developed to address some of the limitations of patient-sourced cell therapies, such as heterogeneity, single-patient manufacturing, need for sufficient cells, extended production time, and cost. For example, engineered CAR natural killer cells, derived from induced pluripotent stem cells, are being developed that incorporate several individual components that together help to enhance persistence and antitumor efficacy (FT596, Fate Therapeutics). Multicombinatorial strategies such as this may be key in reigniting the endogenous immune system and improving efficacy in solid tumor space.Genentech's Priti Hegde, PhD, opened the Translational Science and Emerging Biomarkers plenary, part 1, with a keynote, Biomarker Signaling: Turning Cold Tumors Hot. Individual cancer types can be characterized along the tumor immunity continuum based on immune phenotype (i.e. inflamed or noninflamed) and tumor mutational burden (TMB). How can we generate an immune response signal in noninflamed tumors when most do not achieve the TMB threshold that selects for benefit? Dr. Hedge highlighted two approaches: adaptive immunity, which has the potential to drive memory response, and synthetic immunity, which has the potential to sustain efficacy and drive log kill. An example of an adaptive immunity approach is neoantigen-specific T-cell therapy, in which there are limited but encouraging data demonstrating its ability to promote adaptive immunity in noninflamed tumors. Synthetic immunity approaches include engineered T cells (e.g. NY-ESO SPEAR T cells [GSK/Adaptimmune], BMCA CAR Ts) and bi-specific biologics (e.g. antibodies, BITEs® [Amgen], ImmTAC® [Immunocore]), in which there is a proof of concept that these approaches are feasible in solid tumors and checkpoint inhibitor-refractory hematologic malignancies.One may also need to address the underlying biology to turn cold tumors hot. According to Dr. Hegde, the future of immunotherapy may be highly personalized, and one will need to look at a variety of markers in biopsy specimens using a variety of techniques. This will only be possible if we have: (1) a tissue-conserving, regulatory-grade decentralized platform to be able to run all of these assays in trials and (2) trial designs and statistical analysis plans that enable diagnostic signal-seeking validation and a path for registration.The remainder of the plenary reported on translational data and evolving biomarkers and applications to help support decision-making for IO drug development.Negative results from the Phase 3 study of the therapeutic prostate cancer vaccine PROSTVAC (Bavarian Nordic) show that a combinatorial approach may be needed with vaccines. Similarly, oncolytic viruses may need multiple transgenes and mechanisms to reverse complex immunosuppressive microenvironments. To address this issue, T-Stealth™ oncolytic viruses (BeneVir) can incorporate multiple genes, evade clearance by the innate and adaptive immune systems, and be combined with other drugs and IO agents.With the increasing need for biomarker support, the clinical trial laboratory reality in the IO space is complex. Patrice Hugo, PhD (Q2 Solutions), summarized important features to consider when selecting a lab partner for drug development. Key strategies to successfully introduce innovation in the clinical trial lab space include joint review of pros and cons of technologies, consideration of joint investments, performing Phase 1 specialized testing in niche labs/academic settings with transfer to a central lab, and discussion and planning for regulatory requirements.Advances in positron emission tomography (PET) imaging and radiomics provide a quantitative, noninvasive way to assess the dynamic changes of the immune system. For example, CD8 PET (Imaging Endpoints) may help distinguish between hot and cold tumors and address fundamental questions regarding the role of CD8 cells in the tumor microenvironment.Other unique biomarkers and applications under investigation include MultiOmyx™ (NeoGenomics), a proprietary multi “omic” technology that enables detection and visualization of up to 60 biomarkers on a single slide; immunosequencing (immunoSEQ, Adaptive Biotechnologies), a clinical diagnostic for monitoring clonal expansion and predicting/evaluating response to therapy that can also be used in combination with cellular immunology and computational biology (Multiplexed Identification of T cell Receptor Antigen [MIRA] assay, Adaptive Biotechnologies) to map T-cell receptors; and CANscript™ (Mitra), a personalized ex vivo histoculture approach that can be used to evaluate drug-induced modulation of the tumor microenvironment and predict clinical performance.The IO Novel Technologies and Innovative Solutions plenary showcased companies that have technologies and solutions that will help stakeholders in the IO field advance developments for cancer therapeutics. Presenters included Advaxis, Bioxcel Therapeutics, IAG, Provecs Medical, Rgenix, and Sensei Bio.Andrew Baum, MD (Citi), opened the Financial and Commercial Implications plenary with a keynote, Evaluation and Forecast of the IO Space. He started off by discussing key questions on health-care investors' minds. According to Dr. Baum, “what investors don't like very much about IO is that the technology cycles are short, so you can go from here to zero very quickly very easily.” He cited ipilimumab and the fact that it was quickly eclipsed by anti-PD (L)-1 agents. Another issue is the “paradox of choice,” as there are so many different modalities. “It's almost overwhelming,” he noted, “especially for someone that doesn't have a deep scientific background to interpret a Phase one trial.” Other questions involve primary and secondary resistance, cell therapy manufacturing constraints, minimizing/managing toxicity, and financial toxicity. However, despite these questions, “the good news is the amount of capital, the enthusiasm, and the scientific advancement all mean that we're going to make huge strides in IO, I have no doubt.”Dr. Baum stressed the importance of learning from historic disappointments and noted that we need better biomarkers, better trials, and patience so that the benefits can be extended to more patients. He ended his presentation with a slide showing Citi's top 10 novel IO targets for 2020, in which IL-2/IL-15 took the top spot.Khalil Barrage (Invus) agreed that the IO revolution has led to unprecedented investor enthusiasm for oncology, unlocking massive commercial opportunities. However, the discovery of checkpoints and their curative potential has led to hype in IO drug discovery, resulting in risky behavior. In addition, the flood of capital has lowered potential returns and there are a lot of IO agents in development with poorly validated rationale. As a result, Invus' approach to investing incorporates strategies such as diversification, selectivity, exploring synergistic opportunities, investing where innovation is happening, paying a premium for validated approaches when warranted, and assessing reimbursement.The plenary concluded with a panel discussion on monetizing science: the preparation of an IPO, straight licensing with the transition to a public company, and decision-making on prioritization within portfolios. Key takeaways included strategies for building out scientific and executive talent, the importance of having a scientific advisory board to test out the research, and being prepared to be a public company.The Trends and Collaborations plenary featured presentations by three major industry media companies in the IO field, which discussed new trends and their effect on the investment landscape.BioCentury analyzes IO trends at recent medical meetings using machine learning, began Simone Fishburn, PhD, VP, and Executive Editor. Despite the huge focus on PD (L)-1, academics and companies are aggressively looking for, and finding new targets, with LAG3 topping the list in company oncology pipelines in 2019. CAR T activity is moving into solid tumors, with new constructs and multiple tumor antigens targeted. Immunometabolism and tumor mutation burden are hot topics. Funding for IO start-ups is outstripping other areas, both inside and outside oncology, drawing traditional and corporate investors.According to John D. Carroll (Endpoints News), these trends are supported by global data published by the Cancer Research Institute, which show that there were 3394 IO agents representing 417 targets in the pipeline in 2018, representing a 67% increase over 2017.How are these trends affecting the investment landscape? According to Jeff Bockman, PhD (Cello Health BioConsulting), IO dominates oncology growth, but not sales. Moreover, although IO deals have shown evidence of slowing, whether due to maturation, saturation, or fatigue, and oncology and IO investments remain robust.The Business Development plenary, hosted by Solebury Trout, included panel discussions on partnering, fundraising, and rational investing. The first panel discussed IO partnering strategies from the viewpoint of pharma and academia. According to Dr. Hoos, who the partnering in this space have but there has much and is only that companies have started their unique which will a partnering the for is tumor and the and the companies on the panel and there to be both and with some moving from and on those that can IO and agents are being by most in the and are to play which was for and discussed in the IO space and a number of For example, the panel stressed the importance of at and and on key and as a private on their ecosystem their investors with in the past, key to their than at with the top at the with key the of and companies introduce than need to so that can panel focused on IO investment investors this an time, with a future for many modalities. However, the massive of data is it to to to from a The investors on the panel on a variety of such as the of and whether the data support a or whether an agent has a or has a niche in the IO important is a in their and their to plenary ended with a with of by Solebury Trout, the discussion focused on in the company, with a an For companies looking for highlighted the fact that as a and stressed the need to and where are are some very so both and in to a with a can try and to more like in As industry are companies can be quickly with limited capital, like companies have in the began with a keynote, to led by and MD, of of According to Dr. we are at an in it has from one to has the and of tumor types, agents and trials are and there is an to use to enable to of trials are the way new therapies are developed for cancer, make better and more personalized The of are testing drugs where most (i.e. the order of therapy to about response in the of building an to evaluate drugs and using imaging and biomarker and being by is a platform trial for of biopsy is used to assess and imaging and adaptive The and the are structured to enable and release of agents the The primary is response which is a highly of and and is in biomarker The from biomarker and is to drug to Dr. we want innovation to we have to The focus of new drug development be a a from of metastatic to is a huge is also a huge goal of is to of patients to with and of therapy based on Dr. ended with one of for drug from finding out which drug be to the with two The first Science and Emerging Biomarkers Part was led by PhD, of and to focus on biology and to help predict to Technologies discussed included to enhance antibody therapeutics mechanisms of to immune the for biomarker discovery a and a receptor in second for IO was led by of and was for clinical trial who to it to an IO clinical discussed included an clinical trial study a complex Phase 1 trial in IO and clinical trial for The ended in a panel discussion on the challenges with IO data and to advance to PhD, at the and (i.e. may not the clinical benefit of IO agents. As a result, trends include the use of immune response machine learning to the of imaging and new techniques. The IO plenary up the with a discussion of novel imaging are unique challenges with the use of response at IO clinical as a of complex According to some of these challenges can be by the and of response and including a of in the can be by the use of and and analysis and PhD are being used in with to more from to as as better between and such as the CD8 PET discussed is also an evolving Similarly, imaging using PET an to assess all of a tumors for with a single PET and assess use of a novel three opened with the of with cancer, cancer 10 as metastatic chemotherapy and therapies, and of an immunotherapy trial at the The the that cancer, and those cells in the an of the cells and the cancer has the of being the first to be of metastatic cancer a of to to from in the concluded with some to patients who be in the same the same to with cancer or out as much as you can about to a cancer to to not just one of therapy but several of out about clinical trials and whether you can in The is out there and you as try and on the was a panel discussion on to IO in a The are to but be and and the of a tumor to be want to if the tumor has by the adaptive immune is it by T cells if do have an immunosuppressive factors are in the tumor However, are an important the is the of the cell types are but also and able to look in the is but it doesn't provide all the can all these be with a new plenary for Cell According to Dr. Gulley, therapy has the to on the of cancer there is activity in hematologic but it's is needed to achieve the same effect in solid tumors, so this is where there is much The is to was in studies but the benefit to a of patients. The new technologies and targets discussed in this plenary to do just technology to a T cells their However, in the of approved CAR are According to MD of this as a of of and of He cited a where CD19 in a single cell led to by the CD19 which may have important for manufacturing and other cell therapies. For and the can be with a CAR T or it can be with a new of CAR that the SPEAR are an engineered T-cell of cells that are to a that a antigen in many technology an over CAR T therapy in that it to both and results have in a cancer for which there are no therapies the of noted products a number of over CAR Ts. CAR Ts Chimeric Antigen Receptor developed using the platform are being investigated in and multiple The is to multiple to create T cells with such as the ability to or overcome may an over other therapies in solid tumors in that multiple tumor antigens and there is a of or The technology used to develop the that has and of efficacy have in and the for the has from to to and the is a therapies have the potential to enhance CAR T activity in solid tumors. combination strategies consider both and can be used to enhance cell and and factors in the tumor microenvironment, or and plenary ended with a panel discussion on and clinical to IO therapeutics that will to more and therapies. of the strategies discussed were including a to and products and addressing antigen with or combination In order to we need to address like the when moving from in to the clinical as as cell and the used to create the may the cells, manufacturing and we need to cell therapies so that more patients will have conference concluded with the IO Development plenary, which discussed recent IO clinical The plenary began with an of data for the activity has demonstrated in more than cancer types. The agent has across more than including in is moving into the of therapy, and next-generation biomarkers are to help promising were also for a a and combination immunotherapy and the tumor receptor has to more benefit in Dr. Hoos. However, there is a lot of As a result, “we need to new to the benefit PD Cell therapy has really to the of engineered and we are to the benefit from to solid tumors and overcoming the such as T-cell that in the for patients is
With the rapid development of medical information services, the construction of intelligent hospitals is opening up a new mode of medical treatment in the health care industry. Medical data is gradually becoming more and more important, while it also faces some challenges, among which the most urgent problem to be solved is data security and privacy protection. In the construction of intelligent hospitals, the safety issues among the basic information of patients, the protection of medical information and inter-institutional information sharing have become the focus at this stage. Blockchain technology, with highly security, reliable architecture and algorithm design have operated stably in the financial industry for more than seven years. The related innovative technologies such as distributed ledgers, smart contracts, symmetric encryptions and consensus mechanisms are used widely in many fields. This paper will take the demonstration construction of Chongqing Intelligent Hospital as an example, which tries to combine the blockchain, homomorphic encryption and zero-knowledge proof technology to carry out the research on the security construction and data privacy protection of intelligent hospitals.
Open access
Privacy-Preserving Technologies in Data
Blockchain Technology Applications and Security
Artificial Intelligence in Healthcare and Education
Authentication is the act of confirming the validity of someone’s personal data. In the traditional authentication system, username and password are sent to the server for verification. However, this scheme is not secure, because the password can be sniffed. In addition, the server will keep the user’s password for the authentication. This makes the system vulnerable when the database server is hacked. Zero knowledge authentication allows server to authenticate user without knowing the user’s password. In this research, this scheme was implemented with Guillou-Quisquater protocol. Two login mechanisms were used: file-based certificate with key and local storage. Testing phase was carried out based on the Open Web Application Security Project (OWASP) penetration testing scheme. Furthermore, penetration testing was also performed by an expert based on Acunetix report. Three potential vulnerabilities were found and risk estimation was calculated. According to OWASP risk rating, these vulnerabilities were at the medium level.
Reto E. Koenig, Lukas Laederach, Cédric von Allmen
This paper describes a new but state-of-the-art approach to provide authenticity in mqtt sessions using the means of zero-knowledge-proofs. This approach completely voids session hijacking for the mqtt protocol and provides authenticity without the need for any network-security nor channel-security nor broker-based predefined ACLs. The presented approach does not require the broker to keep any secrets for session handling, what so ever. Moreover, it allows the clientID, which represents the identification for a session, to be publicly known. The presented approach allows completely anonymous but authentic sessions, hence the broker does not need any a priori knowledge of the client-party. As it is especially targeted for applications within the world of IoT, the presented approach is tuned to require only the minimum in extra power in terms of energy and space. The approach does not introduce any new concept, but simply fusions a state-of-the-art cryptographic zero knowledge proof of identity with the existing MQTT-5 specification. Thus no protocol extension is required in order to provide the targeted security properties. The described approach is completely agnostic to the application layer at the client side and is only required during mqtt-session establishment.
Eli Ben‐Sasson, Lior Goldberg, Swastik Kopparty, Shubhangi Saraf
Motivated by the quest for scalable and succinct zero knowledge arguments, we revisit worst-case-to-average-case reductions for linear spaces, raised by [Rothblum, Vadhan, Wigderson, STOC 2013]. The previous state of the art by [Ben-Sasson, Kopparty, Saraf, CCC 2018] showed that if some member of an affine space U is δ-far in relative Hamming distance from a linear code V - this is the worst-case assumption - then most elements of U are almost-δ-far from V - this is the average case. However, this result was known to hold only below the "double Johnson" function of the relative distance δ_V of the code V, i.e., only when δ < 1-(1-δ_V)^(1/4). First, we increase the soundness-bound to the "one-and-a-half Johnson" function of δ_V and show that the average distance of U from V is nearly δ for any worst-case distance δ smaller than 1-(1-δ_V)^(1/3). This bound is tight, which is somewhat surprising because the one-and-a-half Johnson function is unfamiliar in the literature on error correcting codes. To improve soundness further for Reed Solomon codes we sample outside the box. We suggest a new protocol in which the verifier samples a single point z outside the box D on which codewords are evaluated, and asks the prover for the value at z of the interpolating polynomial of a random element of U. Intuitively, the answer provided by the prover "forces" it to choose one codeword from a list of "pretenders" that are close to U. We call this technique Domain Extending for Eliminating Pretenders (DEEP). The DEEP method improves the soundness of the worst-case-to-average-case reduction for RS codes up their list decoding radius. This radius is bounded from below by the Johnson bound, implying average distance is approximately δ for all δ < 1-(1-δ_V)^(1/2). Under a plausible conjecture about the list decoding radius of Reed-Solomon codes, average distance from V is approximately δ for all δ. The DEEP technique can be generalized to all linear codes, giving improved reductions for capacity-achieving list-decodable codes. Finally, we use the DEEP technique to devise two new protocols: - An Interactive Oracle Proof of Proximity (IOPP) for RS codes, called DEEP-FRI. The soundness of the protocol improves upon that of the FRI protocol of [Ben-Sasson et al., ICALP 2018] while retaining linear arithmetic proving complexity and logarithmic verifier arithmetic complexity. - An Interactive Oracle Proof (IOP) for the Algebraic Linking IOP (ALI) protocol used to construct zero knowledge scalable transparent arguments of knowledge (ZK-STARKs) in [Ben-Sasson et al., eprint 2018]. The new protocol, called DEEP-ALI, improves soundness of this crucial step from a small constant < 1/8 to a constant arbitrarily close to 1.