It has been my honor to serve as the 69th president of the Congress of Neurological Surgeons. I was humbled and excited by this opportunity to make a difference. In this address, I hope to stimulate a discussion about how we can and should practice, educate, and influence with reason. How as active voices for science and truth we can cultivate an age of reason for neurosurgery, and medicine as a whole. “A long habit of not thinking a thing wrong gives it a superficial appearance of being right.” These words, written by Thomas Paine, in the pamphlet “Common Sense”, which spurred the United States to fight for its independence, underscore the theme of this year's meeting. Paine would go on to pen The Age of Reason and the Rights of Man, which were some of the first examples of free rational inquiry and critical thinking in the United States. Today, we are living in a time of major upheaval with respect to trust in institutions, acceptance of fact, and recognition of expertise. Twenty-four hour news cycles, constant reminders to engage in social media, and a culture that rewards fame for fame's sake have all contributed to our current state of mistaking skepticism and critical thinking with denialism. Equal time is given to spurious viewpoints, which are touted as equivalent to verifiable truths. To be clear, skepticism is no vice. Suspicion of dogma is not, by itself, a crime. However, what has happened worldwide over the past several years has eroded trust in institutions and neurosurgery is no exception. Much of the loss of trust in the rigor of scientific inquiry can be traced to the deluge of information to which we are exposed. The amount of information being generated across the globe is staggering. Some 500 million tweets are sent daily for a total of 200 billion tweets per year. By the year 2020, the entire digital universe is expected to reach 44 zettabytes (that's a 1 followed by 21 zeroes). That is 40 times more bytes than there are stars in the observable universe. The ability to distinguish reputable information from misinformation is a nearly impossible task when information comes at us so quickly. One can appreciate how easily information can be manipulated. Simple things like reviews on websites can no longer be trusted. In fact, research recently published in the journal Science, has shown that on social media, false stories spread 70% faster than true ones. This phenomenon is not due to bots but rather posts by humans. Conspiracies can be easily concocted by unsubstantiated claims. Correlation is often confused with causation. Myth is reported as fact. Celebrity can now overcome a need for proof. The deluge of scientific misinformation parallels the increase in digital content. Medical journals, once a respected repository of rigorous scientific inquiry have become the source of significant misinformation and dubious peer review. InCites Journal Citation Reports now indexes more than 12 500 journals. Not all journals are equal. Even a journal with a good reputation can sometimes get it wrong. Predatory journals, a term coined only a decade ago, are now commonplace and difficult to differentiate from well-respected titles. These journals often charge a significant article processing fee, lack rigorous, if any, peer review, and take advantage of the “publish or perish” paranoia that pervades academic medicine. One might think that the accessibility of data would allow individuals to make rational choices about the information that they consume. However, there is virtually no regulation of this information. Our patients have more access than ever to the medical literature. However, the democratization of information may have actually undermined scientific trust and understanding. As neurosurgeons, we can differentiate high quality journals from low-quality ones but the public probably cannot tell the difference. Patients now arrive to our clinics armed with misinformation in the form of alternative therapies including potentially harmful supplements or ineffective treatments. This is all creating a situation we would never have imagined 20 yr ago—before the rise of the internet. And it is a sensitive issue—at a time when we are encouraged, and appropriately so, to engage more with our patients and to listen and involve them, this admirable goal has gone awry. Now our first burden is to teach them how to trust the experts, trust us, again. We must be prepared to help our patients differentiate the truth from hype. To reassure them that the treatments we use are based on the best available medical evidence, and why evidence is essential. “I have always strenuously supported the right of every man to his own opinion, however different that opinion might be to mine. He who denies to another this right, makes a slave of himself to his present opinion, because he precludes himself the right of changing it.” Paine wrote that we are entitled to our own opinions, no matter how different yours may be to mine, but we should all retain the right to change it. And we should, if persuaded by solid evidence. As physicians, we are not immune to the pitfall of holding rigidly to our biases. As science changes our practices we are often slow to adapt. Physicians in general continue to practice medicine that is contrary to the evidence. Each year JAMA publishes an update on medical overuse. How many times do you see gabapentin and its derivatives prescribed for sciatica? How about those 2 million-dollar robots your hospital is buying for kidney surgery? It turns out the evidence for their efficacy is very thin. Although neurosurgery is not immune to these hazards, to our credit, we have taken on trials of procedures that have eventually narrowed their scope of use. When a treatment shows promise, we have done the studies to verify their worth. But there may always be grey areas particularly when it comes to certain procedures. “But it is necessary to the happiness of man that he be mentally faithful to himself.” Has our judgment been clouded on occasion by economic incentives? Perhaps but we also get some things right including adopting technology knowing that the benefit will be there for our patients. Above all, when the challenge is adopting new ways of helping patients, it is incumbent on us to perform the appropriate studies when results look promising. No one else can validate or reject—that is a critical part of our responsibility as surgeons. An example from the neuro-oncology world is the EGFR variant 3 vaccine for the treatment of glioblastoma. Compared to historical controls, the vaccine showed tremendous promise but in a randomized controlled trial, it did not hold up. Neither did bevacizumab which also showed promise in Phase II trials but failed in phase III. What if we hadn’t conducted these important randomized trials? How many patients would have been exposed to harmful and useless treatments? Without firm evidence for their use, procedures and treatments can be sold and promoted to an unsuspecting public who can be swindled, or worse, harmed. When this happens, even procedures that may benefit our patients can get caught up in the fray. We need only look to the lay press to see how our profession can be sullied in ways that may seem unfair to us. Poorly investigated procedures and technology can harm our entire profession. What do we do when this misinformation reaches our patients? And they believe it because they read it somewhere? Or someone told them about it? And they come to us with their belief hardened? As Paine tells us, it is an almost impossible task to undo what has been done. To be clear, no one person, political leaning, or socioeconomic class has a monopoly on misinformation. Today we have an example that is compelling, taking place in real time, literally as we sit here today. In perhaps what is the defining misinformation campaign of our times, the link between vaccines and autism. Measles was declared eradicated in the US in 2000 by the CDC and the Americas in 2016 by the Pan American and World Health Organizations thanks to widespread vaccinations. But just a few years later, the disease is making a resurgence due to a decline in vaccinations. Not because of some new untreatable strain or forces beyond our control, or a vaccine so expensive that no one can afford it. No, the resurgence is due to a decline in vaccinations. Parents simply choosing to not vaccinate. In Europe, the numbers are even worse with the continent experiencing nearly 100 000 reported cases. Measles is a terrible disease with a death rate as high as 30% prior to the vaccine. Even today, it has a case fatality rate of 3 in 1000. Nonmedical exemptions are becoming more common and are clearly causing a spike in measles outbreaks. These exemptions are occurring across the political spectrum in communities all over the United States. In my home state of Texas, the number of nonmedical exemptions has been rising dramatically, from just about 2000 in 2002 to over 64 000 in 2019. What has not been going down commensurate with this 30-fold increase in exemptions is the rate of autism. How did we get here? The link between measles, mumps, rubella and autism, stems from an article by Andrew Wakefield in 1998. This study of just 12 children concluded that the vaccine resulted in “developmental regression in a group of previously normal children”. The cause was taken up by celebrities and others resulting in a sustained attack against the safety of vaccines. We have watched the CDC and WHO and pediatric and infectious disease experts speak out with truth and science and reason—and yet too many parents listen to celebrities and anecdotes. The scientists promoting the safety and efficacy of these vaccines get demonized. We have watched truth and reason be trumped by hype, no matter how well intended it is. The effects of this paper linger even today, all over the world, with high rates of belief that vaccines cause autism. Twelve years later, The Lancet published a retraction indicating that “several elements” of the paper were “incorrect”. By then, the damage had been largely done. Now we are experiencing outbreaks all over the country with dangerous, even intentional, exposures of our children to diseases with not insignificant consequences, including death. Change is possible though. After a measles outbreak in Disneyland in 2015, the California legislature passed Senate Bill 227 which banned non-medical exemptions in 2016. This resulted in a record high vaccination rate of over 95% of kindergartners. Medical misinformation is making its way into our hospitals and clinics like never before. We need to push back. We are the experts, and we can make a difference. When we hear something absurd, we should not be afraid to call it out. We must use our expertise to inform patients and the public. Our voices can change minds. There is no risk-free proposition. We do have data on harm from vaccines. The National Vaccine Injury Compensation Program pays out adjudicated claims and collects data from individuals harmed by vaccines. Between 2006 and 2017, 3.4 billion doses of vaccines were distributed in the US. One individual was compensated for every 1 million doses distributed. By comparison, the likelihood of being struck by lightning is 1 in 700 000. This information is rarely, if ever, mentioned in the so-called vaccine debate. Perhaps the most famous example of the harm medical misinformation can cause is the choice Apple co-founder Steve Jobs made regarding his own cancer diagnosis. Jobs was diagnosed with a pancreatic neuroendocrine tumor at age 48. He was advised to undergo potentially curative surgery, but for 9 mo he sought out alternative treatments including vegan diets, acupuncture, cleansings, and even consulted a psychic. He eventually had the surgery but according to many experts this delay almost certainly cost him his life. My wife Lorelei was diagnosed with a similar tumor not so long ago. In 2010, after years of intermittent abdominal pain attributed to reflux, while suffering with severe pain, from what we now know was acute pancreatitis, she went, on her own, to a local emergency room and insisted on getting a computed tomography. It was a shock; she was too healthy to be that sick. We discovered her tumor when our twin boys were barely a year old. We were fortunate to have the best information on how to treat her tumor and after her distal pancreatectomy and splenectomy, she has made a remarkable recovery. I would not be standing here, not as president of the CNS, not as a neurosurgeon, but as the person I am today had it not been for the love and support of my wife. Her journey reminds me that medical science has made a remarkable difference in the lives of countless human beings. What would have happened to someone with a pancreatic tumor 100 yr ago, or even 50 yr ago without the advances that we now take for granted. We are celebrating cures of stage IV cancers even in patients with brain metastases thanks to the diligence and hard work of unsung heroes in laboratories and patients willing to enroll in clinical trials. We wait to hear results of prospective randomized controlled trials because they provide us the best evidence that a treatment is going to work. And the payoff is that our patients survive to live another day, spend time with their families, and enjoy life. We are in a unique position to advocate for our patients by advancing truth, confronting misinformation, and recommending the best treatments, but also by avoiding those that do not work or have not demonstrated efficacy in a rigorous way. We should not be afraid to advise a patient that an “alternative treatment” may expose them to real harm. Choosing “alternative” medicine over standard of care therapies can lead to a significant decrease in survival for patients with cancer. Now I ask—what can we do, each of us? I want you to leave here ready to help our patients by doing something, and each of us will choose our own way. Doing something can take many forms. It is an uphill battle for sure. You will be facing the so-called Dunning-Kruger Effect in which overconfidence and a knowledge deficit go hand in hand. I had the opportunity to meet with Dr Peter Hotez, Dean for the National School of Tropical Medicine at Baylor College of Medicine, and a champion of vaccinations, he told me we need a curriculum that specifically teaches health and science verbal communication in our medical schools. We need to teach the tools to defend science and expertise. We need to speak in declarative sentences and avoid talking down to our patients. He titled his book “Vaccines Did Not Cause Rachel's Autism” in order to simplify the message. I encourage you to read this book, but do not look at the book reviews; they’ve been corrupted by the anti-vaccination movement. “The mind once enlightened cannot again become dark” To conclude, I want to encourage you to counter misinformation and dangerous recommendations in the following ways: We must all stay abreast of the latest and best studies in our field. Familiarize yourselves with ways to differentiate good studies from bad. When patients ask you about a treatment you know to be ineffective or dangerous, it is your opportunity to help that patient Check your arrogance though, our patients deserve honesty, as well as humility and respect Participate in honest and open Morbidity and mortality conferences, Review practice changing peer-reviewed literature with colleagues If misinformation is being spread—say something. We have to be actively engaged. We are the experts. Be critical, be skeptical, but remain open to changing your mind if the evidence convinces you to do so. This is what I am asking. That we are even more forceful in being the guardians of medical truth with our patients and with our communities. To quote Paine one last time: “The mind once enlightened cannot again become dark” Disclosures The author has no personal, financial, or institutional interest in any of the drugs, materials, or devices described in this article.
Many important cryptographic primitives offer probabilistic guarantees of\nsecurity that can be specified as quantitative hyperproperties; these are\nspecifications that stipulate the existence of a certain number of traces in\nthe system satisfying certain constraints. Verification of such hyperproperties\nis extremely challenging because they involve simultaneous reasoning about an\nunbounded number of different traces. In this paper, we introduce a technique\nfor verification of quantitative hyperproperties based on the notion of trace\nenumeration relations. These relations allow us to reduce the problem of\ntrace-counting into one of model-counting of formulas in first-order logic. We\nalso introduce a set of inference rules for machine-checked reasoning about the\nnumber of satisfying solutions to first-order formulas (aka model counting).\nPutting these two components together enables semi-automated verification of\nquantitative hyperproperties on infinite state systems. We use our methodology\nto prove confidentiality of access patterns in Path ORAMs of unbounded size,\nsoundness of a simple interactive zero-knowledge proof protocol as well as\nother applications of quantitative hyperproperties studied in past work.\n
We introduce in this paper the algorithmic aspect of elliptic curves together with their applications. We also recall one of the promising application in the field of zero knowledge proofs with concrete implementations.
In this article, we propose the first self-tallying decentralized e-voting protocol for a ranked-choice voting system based on Borda count. Our protocol does not need any trusted setup or tallying authority to compute the tally. The voters interact through a publicly accessible bulletin board for executing the protocol in a way that is publicly verifiable. Our main protocol consists of two rounds. In the first round, the voters publish their public keys, and in the second round they publish their randomized ballots. All voters provide Non-interactive Zero-Knowledge (NIZK) proofs to show that they have been following the protocol specification honestly without revealing their secret votes. At the end of the election, anyone including a third-party observer will be able to compute the tally without needing any tallying authority. We provide security proofs to show that our protocol guarantees the maximum privacy for each voter. We have implemented our protocol using Ethereum's blockchain as a public bulletin board to record voting operations as publicly verifiable transactions. The experimental data obtained from our tests show the protocol's potential for the real-world deployment.
Alexandros Bampoulidis, A. Bruni, Lukas Helminger, Daniel Kales · 6 authors
Recent work has shown that cell phone mobility data has the unique potential to create accurate models for human mobility and consequently the spread of infected diseases [74]. While prior studies have exclusively relied on a mobile network operator’s subscribers’ aggregated data in modelling disease dynamics, it may be preferable to contemplate aggregated mobility data of infected individuals only. Clearly, naively linking mobile phone data with health records would violate privacy by either allowing to track mobility patterns of infected individuals, leak information on who is infected, or both. This work aims to develop a solution that reports the aggregated mobile phone location data of infected individuals while still maintaining compliance with privacy expectations. To achieve privacy, we use homomorphic encryption, validation techniques derived from zero-knowledge proofs, and differential privacy. Our protocol’s open-source implementation can process eight million subscribers in 70 minutes.
Alexandros Bampoulidis, A. Bruni, Lukas Helminger, Daniel Kales · 6 authors
Recent work has shown that cell phone mobility data has the unique potential\nto create accurate models for human mobility and consequently the spread of\ninfected diseases. While prior studies have exclusively relied on a mobile\nnetwork operator's subscribers' aggregated data in modelling disease dynamics,\nit may be preferable to contemplate aggregated mobility data of infected\nindividuals only. Clearly, naively linking mobile phone data with health\nrecords would violate privacy by either allowing to track mobility patterns of\ninfected individuals, leak information on who is infected, or both. This work\naims to develop a solution that reports the aggregated mobile phone location\ndata of infected individuals while still maintaining compliance with privacy\nexpectations. To achieve privacy, we use homomorphic encryption, validation\ntechniques derived from zero-knowledge proofs, and differential privacy. Our\nprotocol's open-source implementation can process eight million subscribers in\n70 minutes.\n
Jacob Eberhardt, Marco Peise, Dong-Ha Kim, Stefan Tai
The production of renewable energies by individual households typically is small-scale and not profitable without public subsidies, yet a critical factor in preventing further global warming. Unlike market-based peer-to-peer trading solutions, which require households to engage in costly peer-to-peer trading activities, we propose a community-based approach where households in a local distribution grid share the energy they produce in a netting process to maximize internal consumption. The technical instantiation of this idea in real-world energy grids comes with several challenges. Households within a community do not necessarily trust each other or electric utilities. Furthermore, energy consumption data is highly sensitive and must be protected. Further idiosyncrasies of national energy markets, regulatory frameworks, and current grid infrastructure exist. Addressing all these challenges, we propose a blockchain-based system that leverages zero-knowledge off-chain computations to facilitate automated energy sharing within a community in a trustless and privacy-preserving way. We provide a proof- of-concept implementation using the ZoKrates framework for verifiable off-chain computations and the Ethereum Blockchain. To support our claims, we provide evaluation results obtained in the context of a major German national research project on blockchain-based energy networks.
Faulty access control in API-based multi-service setups can lead to violations of consent declarations through unauthorized Third Parties. This threatens Service Providers to lose the trust of their Service Consumers and to be exposed to sensitive fines as defined by the GDPR.Addressing this problem, in this paper, we propose a novel, blockchain-based approach for enabling economically motivated and technically mediated detection of violations of consent declarations in multi-service setups and derive its legal viability from a thorough analysis of the GDPR. The herein introduced Violation Detection mechanism allows for a censorship-resistant and publicly verifiable detection of violations to registered Consent Policies based on off-chain computed violation claims utilizing non-interactive zero-knowledge proofs. The corresponding System Design specifies all required roles and artifacts to integrate the Violation Detection mechanism with standard procedures for consent-based access control. The integration of our system supports Service Providers to fulfill legal requirements and, therefore, paves the way towards automated policy violation detection within GDPR-compliant consent-based access control solutions.
Sean Bowe, Alessandro Chiesa, Matthew Green, Ian Miers · 6 authors
Ledger-based systems that support rich applications often suffer from two limitations. First, validating a transaction requires re-executing the state transition that it attests to. Second, transactions not only reveal which application had a state transition but also reveal the application's internal state.We design, implement, and evaluate ZEXE, a ledger-based system where users can execute offline computations and subsequently produce transactions, attesting to the correctness of these computations, that satisfy two main properties. First, transactions hide all information about the offline computations. Second, transactions can be validated in constant time by anyone, regardless of the offline computation.The core of ZEXE is a construction for a new cryptographic primitive that we introduce, decentralized private computation (DPC) schemes. In order to achieve an efficient implementation of our construction, we leverage tools in the area of cryptographic proofs, including succinct zero knowledge proofs and recursive proof composition. Overall, transactions in ZEXE are 968 bytes regardless of the offline computation, and generating them takes less than 1min plus a time that grows with the offline computation.We demonstrate how to use ZEXE to realize privacy-preserving analogues of popular applications: private user-defined assets and private decentralized exchanges for these assets.
We consider a new class of business-to-business (B2B) blockchain applications that require the execution of specific subroutines to simultaneously satisfy authenticity, compliance, and anonymity. Existing blockchain smart contract protocols do not, either directly or with minor modifications, ensure all the three properties. We present the ACAn smart contract protocol guaranteeing authenticity and compliance over a set of anonymous (unlinkable) subroutine executions. ACAn achieves this through a novel combination of zero-knowledge proofs and multiple Merkle-Tree commitments. We specifically focus on implementing ACAn on Hyperledger Fabric, a popular platform for B2B blockchain applications, which processes transactions in the execute-order-commit framework. The latter, however, leads to performance degradation due to read-write conflicts arising out of multiple clients independently executing the ACAn protocol. We propose enhancements to Hyperledger Fabric's smart contract API to support deferred changes to the shared ledger, allowing us to adapt ACAn so that such conflicts are effectively resolved. Our work provides evidence of significant performance gains due to the proposed enhancements, as well as experimental evaluation of the protocol's privacy preserving components.
Mainstream applications typically require a trusted authority where application clients will connect to obtain a service. In the blockchain decentralized environment, this trusted authority or the leader changes frequently and is selected randomly depending on the protocol. Such procedures may take an unacceptable amount of time or resources to establish the leader causing overheads, latency or processing issues if mainstream applications are to adopt the blockchain. Focusing on these issues, we present Right-of-Stake (RoS), a novel approach in a synchronous blockchain network to deterministically elect a leader or block proposer out of a group of participants, each with different stakes. This procedure is completed in a guaranteed equitable manner while removing the need for Proof-of-Work's (PoW) aggressive-resource computations or Proof-of-Stake's (PoS) inter-node negotiations. Besides, through the use of zero-knowledge range proofs, RoS has a distinct advantage of being able to hide the identity of future leaders until the point when the leader surfaces to propose the block. We also simulate RoS and show that it can recover from Denial-of-Service attacks which have been a point of contention in arguments against deterministic leader election protocols. We view RoS as a possible consensus replacement for blockchains that require an improved leader election process when deployed for mainstream applications.
Blockchain-based cryptocurrencies enable decentralization in transaction systems. The transaction details of traditional cryptocurrencies, e.g. Bitcoin, are public to everyone, which can be a problem in confidential scenarios. To deal with the confidential problem, some current cryptocurrencies adopt confidential transactions to hide the details in proofs. Among all confidential transaction implementations, Bulletproof is the most efficient approach without a trusted setup. In this paper, we analyze Bulletproof's design and show that the computation cost can be further reduced. Based on our analysis, we propose Shellproof, which is only half of the computation cost of Bulletproof. Experimental results show Shellproof can preserve the advantages of Bulletproof and is much more efficient than Bulletproof.
Blockchain Technology Applications and Security
Cryptography and Data Security
Advanced Steganography and Watermarking Techniques
Jiaheng Zhang, Tiancheng Xie, Yupeng Zhang, Dawn Song
We present a new succinct zero knowledge argument scheme for layered arithmetic circuits without trusted setup. The prover time is O(C + nlogn) and the proof size is O(D logC +log2n) for a D-depth circuit with n inputs and C gates. The verification time is also succinct, O(D logC + log2n), if the circuit is structured. Our scheme only uses lightweight cryptographic primitives such as collision-resistant hash functions and is plausibly post-quantum secure. We implement a zero knowledge argument system, Virgo, based on our new scheme and compare its performance to existing schemes. Experiments show that it only takes 53 seconds to generate a proof for a circuit computing a Merkle tree with 256 leaves, at least an order of magnitude faster than all other succinct zero knowledge argument schemes. The verification time is 50ms, and the proof size is 253KB, both competitive to existing systems.Underlying Virgo is a new transparent zero knowledge verifiable polynomial delegation scheme with logarithmic proof size and verification time. The scheme is in the interactive oracle proof model and may be of independent interest.
The paper deals with the concept of homomorphic encryption and the possibility of its use in the mechanism of electronic voting. One of the problematic requirements for electronic voting systems is voter anonymity. On the one hand, each voter must be identified, and on the other, the content of his or her vote must be unknown. Currently, the methods and mechanisms used in real voting systems do not provide real anonymity. Therefore, both theoretical and practical content is an urgent and necessary problem of developing mechanisms for anonymous counting of votes with the protection of their distortion. The paper also provides a general analysis of the security level of prospective homomorphic encryption schemes. The essence of homomorphic encryption is that there is some set of operations whose result of executing over ciphertexts (with subsequent decryption) coincides with similar actions over plaintexts. Homomorphic encryption allows you to perform some calculations on information without having access to the information itself. However, there are a number of problems when trying to apply such calculations. The main ones are the choice of the method of asymmetric encryption, which provides the necessary cryptographic stability from both classical and quantum attacks, the identification of possible candidates for asymmetric cryptotransformations in homomorphic encryption, their evaluation of comparison with each other, and, of course, the choice of the most rational for a given multiple restrictions. The asymmetric schemes of homomorphic encryption are compared using the hierarchy analysis process. The method of asymmetric encryption with zero knowledge is substantiated. The objective of this article is to substantiate the possibilities, conditions, and constraints on the use of standardized asymmetric cryptotransformations in the creation of modern homomorphic encryption-type transformations, when anonymity of electronic voting and practical implementation of anonymous voting based on proof of zero knowledge must be guaranteed.
The cryptographic algorithm has been gradually improved in design, but its implementations are vulnerable to side‐channel analysis (SCA). Generally speaking, adding a mask to the primitive is the best way to counteract SCA. In the high‐order mask, the key to affecting performance and security lies in the multiplication design. Based on the research of the advanced encryption standard (AES) algorithm, internal round function structure, and zero‐knowledge proof, a high‐order AES mask scheme is designed to optimise the implementation. In this scheme, the substitution‐box protects sensitive variables in the algorithm with the use of secure multiplication and secure inversion by column. The scheme named as in columns higher‐order mask (ICHM), features low cost and high security. The result of the experiment proves the security and effectiveness of the ICHM.
Cryptographic Implementations and Security
Chaos-based Image/Signal Encryption
Physical Unclonable Functions (PUFs) and Hardware Security
Securing the traceability of products in the supply chain is an urgent issue. Recently, supply chain systems that use public blockchain (PBC) have been proposed. In these systems, PBC is used as a common database shared between supply chain parties to secure the integrity and reliability of distribution information such as ownership transfer records. Thus, these systems secure a high level of traceability in the supply chain. However, the distribution information, which can be private information, is made public since the information recorded in PBC can be read by anyone. In this paper, we propose a method for preserving privacy while securing traceability in a supply chain system using PBC. The proposed method preserves privacy by concealing the distribution information via encryption. In addition, the proposed method ensures distribution among legitimate supply chain parties while concealing their blockchain address by using a zero-knowledge proof to prove their authenticity. We implement the proposed method on Ethereum smart contracts and evaluate cost performance based on transaction fees. The results show that the fee per party is at most 2.6 USD.
Resource constraints have prevented comprehensive cryptography and multifactor authentication in numerous Internet of Things (IoT) connectivity scenarios. Existing IoT systems generally adopt lightweight security protocols that lead to compromise and privacy leakage. Edge computing enables better access control and privacy protection, furthermore, blockchain architecture has achieved a trusted store of value by open-source and distributed consensus mechanisms. To embrace these new paradigms, we propose a scheme that employs one-time association multitasking proofs for peer to local authentication (OTMP-P2L). The scheme chooses relevant nondeterministic polynomial (NP) problem tasks, and manages localized trust and anonymity by using smart devices such as phones and pads, thereby enabling IoT devices to autonomously perform consensus validation with an enhanced message authentication code. This nested code is a one-time zero-knowledge proof that comprises multiple logic verification arguments. To increase diversity and reduce the workload of each one, these arguments are chained by a method that establishes some of the inputs of the following task from the output of previous tasks. We implemented a smart lock system and confirmed that the scheme outperforms IoT authentication methods. The result demonstrates superior flexibility through dynamic difficulty strategies and succinct non-interactive peer-to-peer (P2P) verification.
Summary The Bitcoin model originated blockchain architectures and inspired their further development. Blockchain architectures are still most commonly associated with currency applications, and with financial speculation. Bitcoin's rewards for Proof of Work mining became the default consensus technique for blockchains. As an alternative to reward mechanisms for blockchain maintenance, we propose punishment mechanisms for neglecting to maintain the blockchain (provided participants are intrinsically motivated to be beneficiaries of the blockchain application). Punishment not Reward is convincing for enterprise mission critical blockchain applications, and potential punishment mechanisms include denial of service and/or revocation of confidentiality . This obviates the need for reward via cryptocurrencies, along with their attendant volatility, insecure ecosystem, and market manipulation demerits. The privacy concerns of competing entities participating in a blockchain application are prima facie in conflict with the needs of the community to be able to inflict punishment mechanisms. Conflicts of this kind can be addressed via sophisticated cryptographic techniques such as secret sharing, multiparty computation, zero‐knowledge proofs, and so on, which play a vital role. We stress the importance of correctly balancing all application specific interests in the engineering of blockchain applications, so that the mix of incentives and disincentives is stabilizing.
Alexander Frolov, Alexander Vinnikov, S.D. Polyakova
We present the IT solutions for educational modeling of non-interactive zero knowledge (NIZK) cryptographic public keys certification protocols. Certified public keys can then be used in a variety of non-interactive protocols, for example, in protocols using technique designated verifier proofs. The solution is based on algebraic means provided by MPEI algebraic processor. The IT solution supports the following educational purposes: obtaining practical skills of remote implementation of multiple non-interactive oblivious transfer and of non-interactive zero-knowledge proof protocol, mastering the methods of a remote automatic modeling of cryptographic protocols and of non-interactive public keys certification, and the technique designated verifier proofs.
Xun Yi, Russell Paulet, Elisa Bertino, Fang-Yu Rao
In this paper we consider the problem where a client wishes to subscribe to some product or service provided by a server, but maintain their anonymity. At the same time, the server must be able to authenticate the client as a genuine user and be able to discontinue (or revoke) the client's access if the subscription fees are not paid. Current solutions for this problem are typically constructed using some combination of blind signature or zero-knowledge proof techniques, which do not directly support client revocation (that is, revoking a user before expiry of their secret value). In this paper, we present a solution for this problem on the basis of the broadcast encryption scheme, suggested by Boneh et al., by which the server can broadcast a secret to a group of legitimate clients. Our solution allows the registered client to log into the server anonymously and also supports client revocation by the server. Our solution can be used in many applications, such as location-based queries. We formally define a model for our anonymous subscription protocol and prove the security of our solution under this model. In addition, we present experimental results from an implementation of our protocol. These experimental results demonstrate that our protocol is practical.
A key communication technology in smart cities and smart buildings for automation is RFID. Proving the simultaneous presence of a group of RFID-tagged objects is a practical need in many application areas within this domain. Some examples of this include vehicle fleets, smart parking, safety in public places (smart cities), security and access control (smart buildings), and asset location (supply chain system, health care industry). Security, privacy, and efficiency are central issues when designing such a grouping-proof protocol. This work is motivated by Sundaresan et al.'s grouping-proof protocol, which applies zero-knowledge techniques. In this paper, we propose a lightweight, offline, serial-dependency grouping-proof protocol. Compared to existing grouping-proof protocols, our scheme improves on efficiency, scalability, security, and communication cost. It resists well-known attacks on grouping-proofs including tag/reader impersonation, tracking, replay, desynchronization, and message integrity.
With the development of precise positioning technology, a growing number of location-based services (LBS) emerge. For example, visit a specific place to get the corresponding reward. This also leads to location fraud by illegal users in order to gain benefits. Thus, it is necessary to verify location certificates provided by users. However, present proof of location systems are deficient in verifying users’ location certificates while protecting users’ privacy. Users do not flexibly control their location certificates either. Based on blockchain, a kind of distributed proof of location system architecture was proposed and based on the proposed system architecture, a kind of proof of location protocol with zero-knowledge proof was proposed further. With the proposed architecture and the protocol, the proposed proof of location system allows users to freely select disclosed certificate parameters and positional accuracy according to their needs so that hierarchical location privacy protection was achieved.