Blockchain Papers

M. Prakash, K. Ramesh

No abstract is available for this record.

Alhad Daftardar, Brandon Reagen, Siddharth Garg

Zero-Knowledge Proofs (ZKPs) are an emergent paradigm in verifiable computing. In the context of applications like cloud computing, ZKPs can be used by a client (called the verifier) to verify the service provider (called the prover) is in fact performing the correct computation based on a public input. A recently prominent variant of ZKPs is zkSNARKs, generating succinct proofs that can be rapidly verified by the end user. However, proof generation itself is very time consuming per transaction. Two key primitives in proof generation are the Number Theoretic Transform (NTT) and Multi-scalar Multiplication (MSM). These primitives are prime candidates for hardware acceleration, and prior works have looked at GPU implementations and custom RTL. However, both algorithms involve complex dataflow patterns -- standard NTTs have irregular memory accesses for butterfly computations from stage to stage, and MSMs using Pippenger's algorithm have data-dependent memory accesses for partial sum calculations. We present SZKP, a scalable accelerator framework that is the first ASIC to accelerate an entire proof on-chip by leveraging structured dataflows for both NTTs and MSMs. SZKP achieves conservative full-proof speedups of over 400$\times$, 3$\times$, and 12$\times$ over CPU, ASIC, and GPU implementations.

Lin Qi, Binbin Gu, Faisal Nawab

The interest in building blockchain Decentralized Applications (DApps) has been growing over the past few years. DApps are implemented as smart contracts which are programs that are maintained by a blockchain network. Building DApps, however, faces many challenges—most notably the performance and monetary overhead of writing to blockchain smart contracts. To overcome this challenge, many DApp developers have explored utilizingoff-chainresources—nodes outside of the blockchain network—to offload part of the processing and storage. In this paper, we propose RollStore, a data indexing solution for hybrid onchain-offchain DApps. RollStore provides efficiency in terms of reduced cost and latency, as well as security in terms of tolerating Byzantine (i.e., malicious) off-chain nodes. RollStore achieves this by: (1) a three-stage commitment strategy where each stage represents a point in a performance-security trade-off—i.e., the first stage is fast but less secure while the last stage is slower but more secure. (2) utilizing zero-knowledge (zk) proofs to enable the on-chain smart contract to verify off-chain operations with a small cost. (3) Combining Log-Structured Merge (LSM) trees and Merkle Mountain Range (MMR) trees to efficiently enable both access and verification of indexed data. We experimentally evaluate the cost and performance benefits of RollStore while comparing with BlockchainDB and BigChainDB.

Keyi Guo, Haoyu Ren, Peiyu Wang

In recent years, blockchain technology has evolved significantly, enabling a decentralized network application model that offers both user anonymity and transparency. This unique characteristic of blockchain has led to its adoption in various sectors, including healthcare, finance, and transportation. The advancement of modern zero-knowledge proof technology has further enhanced blockchain's applications across these fields, bolstering privacy protection. Zero-knowledge proofs have become a key mechanism in blockchain smart contracts, offering a balance between transparency and privacy. Moreover, the integration of zero-knowledge proof technology with blockchain is facilitating technical advancements in areas facing challenges, such as autonomous driving technology. It is also addressing security concerns in more established technologies like the Internet of Things. This synergy between zero-knowledge proof and blockchain technologies is paving the way for innovative solutions across a wide range of applications.

V. A. Samaranayake

Flight controllers here looking very carefully at the situation. Obviously a major malfunction.” The words of Steve Nesbitt, the public affairs officer at Houston, are etched indelibly in all of us who watched the launch of the space shuttle Challenger on the morning of 28 January 1986. Ironically, the phrase “major malfunction” aptly describes not only the physical disintegration of the shuttle, but also the managerial and engineering missteps that led to this tragedy, taking the lives of seven astronauts, including the high school teacher Christa McAuliffe. Fingers have been pointed at faulty engineering design, poor communication, conflicting engineering and managerial goals, the culture at NASA, as well as political pressure. But to a statistician, the lack of sound statistical reasoning and the failure to use appropriate data and visual aides to convince a set of sceptical administrators – especially at the crucial juncture of determining launch risk – seem to constitute an equally serious misstep. Engineers at Morton Thiokol, the solid rocket booster (SRB) manufacturer in Utah, had concerns about the field joints on the boosters (also referred to as the solid rocket motors) for many years.1 It is one of these joints that failed during the Challenger launch, setting off a cascading series of events that led to the destruction of the shuttle. To the casual observer, an SRB may seem to be a single metal cylinder running the whole length of the booster, but it consists of four connected segments each of which is more than 25 feet long. Tang-and-clevis connections join the segments (see Figure 1). The connections, referred to as field joints, are then locked using 177 steel pins.2 To prevent hot gasses from escaping through the joints during the ignition of the solid fuel inside the boosters, engineers placed two O-rings made of synthetic rubber in machined grooves on the inside surface of the clevis. Flame-proof zinc chromate putty sitting between the rocket fuel and the O-rings acted as a pressure transmission mechanism during ignition, which helped extrude the O-rings into the grooves they were sitting in, forcing the rubber to seal any gap between the metal surfaces.1 The secondary O-ring was supposed to take over if the primary ring failed. Illustration of the field joint connection. But there was a potential problem. Engineers noted that ignition of the solid rocket caused the shell of the boosters to distort under pressure, triggering what was labelled “joint rotation”, creating a momentary gap to open near the O-ring slots. This caused the primary O-ring to extrude into the gap and the secondary O-ring to “become completely disengaged from its sealing surface on the tang”.3 Thus, in practice there was no redundancy in the system, and hence the field joints were reassigned from Criticality 1R (R designating redundancy) to Criticality 1, meaning that the failure of the joint would result in loss of life or vehicle.3 But the continued belief in this redundancy by decision-makers at NASA proved disastrous. There was another critical issue, initially not given much thought. Morton Thiokol engineers banked on the elastic ability of the O-rings to fill any gaps, providing a proper seal. It was common knowledge that low temperatures can make synthetic rubber harder.4 This could limit the O-ring’s ability to deform from the original circular cross-sectional shape into a configuration necessary to provide a proper seal, but the engineers claimed that they had no real data on this.2 The first space shuttle flight, named “Space Transport System 1” (STS-1) was launched on 12 April 1981. Between then and Challenger, 22 shuttle flights took place without any outwardly troubling incidents, but post-flight inspection of recovered booster rockets revealed 10 field joint O-rings with erosion due to hot gasses.3 In fact, the primary O-ring on a field joint of the second shuttle flight, STS-2, showed a 0.053-inch-deep erosion.3 Note that the cross-section diameter of the O-ring is 0.272 inches.4 It was, however, flight STS-41B in February 1984 that prompted engineers to file a problem report, but they went on to state that recent tests indicated that the secondary O-ring would provide “adequate backup”.3 This assessment was questioned by Keith Coates at the Marshall Space Flight Center in a memorandum to George Hardy, the deputy director of engineering at Marshall. Hardy eventually played a role in the eleventh-hour teleconference that led to the decision to launch Challenger. To their credit, Morton Thiokol engineers conducted a series of experiments to determine if the O-rings with a 0.095-inch erosion depth (0.005 inches greater than the maximum possible erosion limit of 0.09 inches they arrived at by computations), would still seal properly under various pressures. They found them to do so even at pressures of 3,000 psi and concluded that “this [O-ring erosion] is not a constraint to future launches” (tinyurl.com/uj5x5p5t). Their results led them to believe that joint erosion was an “acceptable risk” because 0.053 inches is well within their upper limit of 0.09 inches.2 It appears that engineers failed to consider the random nature of erosion and that the probability of it exceeding the 0.09-inch limit may not be zero or negligible. In other words, there is no evidence that the engineers accounted for the inherent variability in the data in a statistically valid fashion when estimating the risk of failure. The Challenger (STS-51-L) flight was scheduled to be the first in 1986, but due to delays associated with many factors and the last-minute scrubbing on 27 January the launch was finally rescheduled for 9:38 a.m. Eastern Time on 28 January.2 This delay placed the launch on a day with a forecast of temperatures in the low 20s Fahrenheit during early morning hours and 26°F at launch time.1,4 Morton Thiokol engineers and others were concerned about the cold-weather launch, especially because of their experience with an earlier space shuttle launch in January 1985. The calculated O-ring temperature on that space shuttle (STS-51-C) was 53°F at launch, the lowest temperature encountered by the shuttle up to that time.3 On recovery, the booster rockets showed both impingement and “blow-by” erosions. The former is caused by hot gases impinging on an already sealed O-ring, while the latter occurs when it has not sealed, a much more serious event where hot gases “blow by” the primary O-ring and impinge on the secondary one. This experience in 1985 was the first-time engineers observed evidence of the hot gasses penetrating the primary O-ring, with blackened grease found between the two O-rings.3 Even though they were very concerned about the 1985 event and concluded that “low temperatures enhanced the probability of blow-by,” they went on to state that, for Challenger one year later, “the condition is not desirable but is acceptable”.3 This may be because they did not expect Florida weather to get that cold often and their belief in apparent redundancy due to the inclusion of the secondary O-ring. In spite of this “acceptable” recommendation, erosion was a serious concern to Thiokol engineers especially because Challenger was to be launched at temperatures 30°F below that of STS-51-C. Having sat in cold weather for many hours, they calculated that Challenger’s O-rings would be at 29°F at 9 a.m., with gradual warming to 38°F by 2 p.m.1 Among the Morton Thiokol engineers who had very serious worries about the potential for a disastrous failure of the field joints were Allan McDonald, Roger Boisjoly, Robert Ebeling, and Arnold (Arnie) Thomson. They all played key roles in trying to persuade the decision-makers not to launch, but ultimately failed. At a teleconference held at 5:45 pm the day before the launch, Morton Thiokol engineers recommended delaying the launch until later in the day. But since not everyone was able to participate and conduct a thorough discussion, a second teleconference, between Morton Thiokol engineers, managers, as well as those representing the Kennedy Space Center in Florida and the Marshall Space Flight Center in Huntsville, Alabama, was scheduled for 8:15 p.m.2 Morton Thiokol engineers prepared 13 charts, mostly handwritten, to be presented at this teleconference. One addressed the temperature effect on sealing abilities and another focused on the effect of temperature on the O-ring material.4 A key chart that led to a misleading conclusion listed cases of erosion in both field and nozzle joints, the latter referring to the joint at the nozzle of the booster rocket.4 The intent of the Morton Thiokol engineers was to point out that the “worst case [O-ring] condition ever observed” occurred in shuttle STS-51-C in 1985, which was launched under the coldest conditions ever. But this strategy seemingly backfired, because shuttle STS-61-A – the ninth and last successful flight of the space shuttle Challenger before the disaster, which had the only other serious blow-by erosion, was launched during 78°F weather, with a calculated O-ring temperature of 75°F. Figure 2 illustrates the O-ring distress data presented by Thiokol engineers in graphical form rather than in the list form used by Thiokol. O-ring thermal distress as a function of temperature.3 Note that each launch can have more than one incident because of multiple field joints. It is not surprising that Larry Mulloy, the manager of the Space Shuttle Solid Rocket Booster Program at Marshall Space Flight Center, retorted: “How then can you conclude that temperature has anything to do with blowby?”4 After all, blow-by, the more serious type of erosion, occurred on both the hottest and the coldest rocket motors. Boisjoly tried to explain that the blow-by erosions seen in STS-51-C and STS-61-A were qualitatively different. The former had primary O-ring erosion and jet-black soot over the secondary O-ring, while in the latter there was no primary O-ring erosion and only light grey coating of the secondary O-ring.4 But the damage was already done. Morton Thiokol engineers’ recommendation (given at this second meeting) that no launch should be made below 53°F was met with derision. Mulloy exclaimed: “My God, Thiokol, when do you want me to launch, next April?”2 Mulloy went on to say that all the data when considered together does not appear to show any correlation between temperature and erosion and, moreover, if the cold temperature “slowed” the seating of the primary, the secondary O-ring “would seal the joint”.2 George Hardy added to this pressure to launch, saying he was “appalled” by Morton Thiokol’s recommendation.3 In fairness to Hardy, he did state that no launch should be made without Thiokol’s concurrence.4 The data set from which Figure 2 is derived is not the only one that mislead Mulloy. Engineers also presented a chart that showed no leakage past O-ring seals at 30°F and at 78°F using data obtained from a bench test done on joints at less than full scale with boosters mounted horizontally. Sealing pressure in this test was applied using inert argon gas, which is very difficult to detect for leakage.4 Only two data points were presented, one at each temperature.2 A respectable statistician may be hesitant to make a conclusion based on just two data points. Moreover, the data came from a test that did not reflect real field conditions. But apparently the NASA hierarchy was influenced by such data. Seeing no agreement, Morton Thiokol manager Joe Kilminster called for a five-minute caucus which lasted for almost 30 minutes. Morton Thiokol managers, ignoring the concerns of their engineers, then voted to recommend the launch. Boisjoly and Thomson repeated their arguments to the managers to no avail. This decision, of course, resulted in a very sad ending. As reported in his New York Times obituary, engineer Robert Ebeling told his daughter, “The Challenger is going to blow up. Everyone is going to die”, before leaving to watch the launch.5 He fully understood the precarious nature of the decision NASA had taken. What stopped Ebeling and others from effectively conveying this sense of danger to the decision-makers such as Mulloy and Hardy? As engineers intimately involved with the design and manufacture of the SRBs, Ebeling, Boisjoly, and others understood the inherent danger of launching in cold weather. Why, then, did they fail to impress upon their superiors what they knew in their bones to be true? Ben Powers at Marshall Space Center had this to say after the teleconference: “I don’t believe they did a convincing job of presenting their data”.2 He is definitely correct. The report of the Presidential Commission (also known as the Rogers Commission) appointed to investigate the Challenger disaster contrasts Figure 2, which summarises the data shown by Morton Thiokol engineers, to Figure 3 which encompasses the history of all flights, not just the ones with erosion. It clearly shows that the vast majority of launches with O-ring temperatures above 65°F had no erosion and all launches above 75°F produced no erosion. In contrast, all launches below 65°F had one or more erosion incidences. You do not have to be a trained statistician to recognise this. Clearly correlation between temperature and O-ring erosion exists, as opposed to what Mulloy thought. Even NASA management, who were very keen to keep a steady schedule of launches, may have been swayed by this figure, at least to the extent of postponing the launch until the afternoon of 28 January, when the temperature was forecast to rise well above freezing, or wait for a much warmer day, which is not uncommon for Florida even in January. The history of all flights, not just those with erosion incidences, showing erosion in all launches below 65°F. At the end of their investigation the Rogers Commission stated several findings. A finding that reveals the inadequacy of NASA’s statistical analyses states: “A careful analysis of the flight history of O-ring performance would have revealed the correlation of O-ring damage and low temperature. Neither NASA nor Thiokol carried out such an analysis; consequently, they were unprepared to properly evaluate the risks of launching the 51-L mission in conditions more extreme than they had encountered before”.3 Another finding, based on commissioner Richard Feynman’s comments, was: “NASA and Thiokol accepted escalating risk apparently because they ‘got away with it last time.’ … ‘a kind of Russian roulette.’ [The Shuttle] flies [with O-ring erosion] and nothing happens. Then it is suggested, therefore, that the risk is no longer so high for the next flights. We can lower our standards a little bit because we got away with it last time. … You got away with it but it shouldn’t be done over and over again like that.” This is simple probabilistic reasoning: if the probability of success in a given launch is 0.95, then, assuming each launch to be an independent event, the probability you will succeed in all 24 consecutive launches is a very low 0.292! As was implied earlier in this article, lack of formal risk assessment seemed to be an obvious deficiency within NASA. The United States House of Representatives Committee on Science and Technology’s report on the Challenger accident agrees, stating: “In concurrence with the Rogers Commission, the Committee confirms that the safety, reliability, and quality assurance programs within NASA were grossly inadequate, but in addition recommends that NASA review its risk management activities to define a complete risk management program.”6 Apart from the criticisms levelled by the Rogers Commission and the House Committee, others have also taken issue with the data on which NASA’s decision to launch Challenger was made. Edward Tufte, in his book Visual Explanations, refers to “a scandalous discrepancy between the intellectual tasks at hand and the images created to serve those tasks. As analytical graphics, the displays failed to reveal a risk that was in fact present. As presentation graphics, the displays failed to persuade government officials that a cold-weather launch might be dangerous.”7 Fredrick Lighthall at the University of Chicago, who conducted an examination of the circumstances related to the Challenger disaster, makes some scathing criticisms.8 One such criticism is that not a single chart prepared by Morton Thiokol engineers for the teleconference presented O-ring anomaly counts and temperature in relation to one another. In his conclusion Lighthall states that the “data presented in chart form during the teleconference were essentially irrelevant to the causal question that Thiokol engineers were attempting to answer”. He goes on to say that that “none of the participants had ever learned, or had long since forgotten, elementary ideas and methods of statistical analysis and inference”. Furthermore, “these failures of thought and perception were not from a lack of sophisticated expertise but from lack of simple, elementary understandings and methods”. It is unfortunate that the “lack of simple, elementary understandings and methods” produced a deadly outcome and tarnished the recognition that hard-working NASA and Morton Thiokol engineers should have received for making the space shuttle a reality. As Malcolm McConnell, the author of the book Challenger: A Major Malfunction,1 states: “the rank-and-file people of NASA are among the hardest working, most productive, and most talented employees in the federal government”. Yet their failure to use simple visualisation tools to present the full story about the link between temperature and O-ring erosion resulted in tarnished reputations, not to mention the tragic ending of seven lives. There is a hard-learned lesson in this. For sustained success, high-technological achievements should be coupled with data-driven risk assessment of these technologies, and then the resulting information must be presented clearly and unambiguously to facilitate sound decision-making. Without such clarity, faulty decisions are going to be made, and even the highest technical achievements are going to fall flat on their face.

Jinyi Zhao, Zhenying Wen, Taowei Chen, Yimin Yu

This paper present a novel blockchain CP-ABE (Ciphertext-Policy Attribute-Based Encryption) data ciphertext sharing scheme, leveraging decentralized proxy re-encryption. It utilizes Ethereum blockchain and zero-knowledge proof technologies to develop a blockchain key management system for multiparty secure computation. This system aims to mitigate heavy computation and key leakage risks associated with traditional centralized CP-ABE systems. The approach begins with the design of a distributed master key generation and distribution protocol within the data ciphertext access control, deploying the UMBRAL-based proxy re-encryption technology on blockchain for key management system. Moreover, the paper uses ERC1155 to mint transferable NFTs for blockchain transactions in data sharing and access control. Through simulation experiments, our scheme demonstrates improved scalability in blockchain ciphertext data transactions and storage, alongside a significant decrease in the Gas costs of on-chain data asset transactions. Furthermore, our methodology not only augments the safety of distributed key management but also realizes high computational efficiency and swift query response, particularly in scenarios of high concurrency.

Olumide Samuel Ogungbemi

The digital transformation of the real estate industry is being significantly influenced by blockchain technology and smart contracts, which promise enhanced efficiency, transparency, and security in transactions. This study aims to develop a secure and efficient smart contract management protocol that balances the benefits of blockchain with robust data privacy practices. The methodology involves descriptive analytics of transaction data from the Ethereum blockchain, feasibility studies using synthetic transaction data, and a regulatory compliance analysis to map the impact of different regions' regulations on blockchain adoption in real estate. The findings reveal that while smart contracts can automate various processes and reduce reliance on intermediaries, challenges related to data privacy and regulatory compliance persist. Higher privacy features in smart contracts are associated with increased execution costs, indicating a trade-off between privacy and cost efficiency. Smart contracts with privacy level 3 had an execution cost of 0.025 ETH, compared to those with privacy level 1 at 0.02 ETH. Integrating permissioned blockchains and zero-knowledge proofs offers a promising solution, though their complexity limits broader adoption. Zero-knowledge proofs maintained high privacy (achieving privacy levels of up to 0.76) at a reasonable computational cost (proof generation time of 1.9 seconds). Thus, the integration of permissioned blockchains and zero-knowledge proofs offers a promising pathway to address these challenges. However, the complexity of these techniques requires specialized knowledge, limiting broader adoption. The study concludes with recommendations to develop specialized training programs, collaborate on regulatory frameworks, invest in advanced cryptographic research, and implement targeted strategies to overcome adoption barriers. These efforts will contribute to the digital transformation of asset management, fostering innovation and enhancing the overall efficiency of real estate transactions.

Sandip Das, A. Lahiri, Soumen Nandi, Sagnik Sen · 5 authors

An ( n , m ) -graph is characterized by n types of arcs and m types of edges. A homomorphism of an ( n , m ) -graph G to an ( n , m ) -graph H , is a vertex mapping that preserves adjacency, direction, and type. The ( n , m ) -chromatic number of G , denoted by χ n , m ( G ) , is the minimum value of | V ( H ) | such that there exists a homomorphism of G to H . The theory of homomorphisms of ( n , m ) -graphs have connections with graph theoretic concepts like harmonious coloring, nowhere-zero flows; with other mathematical topics like binary predicate logic , Coxeter groups; and has application to the Query Evaluation Problem (QEP) in graph database. In this article, we show that the arboricity of G is bounded by a function of χ n , m ( G ) but not the other way around. Additionally, we show that the acyclic chromatic number of G is bounded by a function of χ n , m ( G ) , a result already known in the reverse direction. Furthermore, we prove that the ( n , m ) -chromatic number for the family of graphs with maximum average degree less than 2 + 2 4 ( 2 n + m ) − 1 , including the subfamily of planar graphs with girth at least 8 ( 2 n + m ) , equals 2 ( 2 n + m ) + 1 . This improves upon previous findings, which proved the ( n , m ) -chromatic number for planar graphs with girth at least 10 ( 2 n + m ) − 4 is 2 ( 2 n + m ) + 1 . It is established that the ( n , m ) -chromatic number for the family T 2 of partial 2-trees is both bounded below and above by quadratic functions of ( 2 n + m ) , with the lower bound being tight when ( 2 n + m ) = 2 . We prove 14 ≤ χ ( 0 , 3 ) ( T 2 ) ≤ 15 and 14 ≤ χ ( 1 , 1 ) ( T 2 ) ≤ 21 which improves both known lower bounds and the former upper bound. Moreover, for the latter upper bound, to the best of our knowledge we provide the first theoretical proof.

Ariel Chan, Chijuan Hu

As outlined in the Paris Agreement, the global commitment to achieving net-zero emissions by 2050 necessitates a multifaceted approach encompassing clean energy initiatives and carbon taxation.Higher education institutions, recognizing their role as key contributors to sustainability, are increasingly focusing on reducing their carbon footprint.The teaching laboratories, essential for various disciplines, contribute significantly to the university's carbon footprint.In this study, we applied the common practices of Life Cycle Analysis (LCA) in the industry to the Unit Operations Laboratory, which resembles the industrial settings yet focuses on teaching and learning that may not have set production scopes nor define operation conditions and processes (i.e. for learning purposes and study impact of various factors on common chemical processes).As learning is the main objective in undergraduate laboratories, LCA methodologies related to laboratory equipment and incorporating technical information on global climate initiatives, clean energy, and the Paris Agreement need to be followed, but some modifications to make such calculations possible.To illustrate the feasibility of this approach, a case study on bioethanol production through yeast fermentation and subsequent distillation processes is employed as a proof-ofconcept.This case study serves as a platform for estimating LCA and redesigning experiments with the aim of reducing the carbon footprint.Since not all chemical process units are designed the same (i.e.sizes, power/production capacity), this project is a collaborative effort internationally amongst universities with similar equipment but different sizes.The carbon footprint approaches, and the preliminary data collected can enable fine-tuning and test the robustness of the approaches and models.The Unit Operations Laboratory emerges as a valuable platform for students to assess their carbon footprint and actively engage in practical LCA applications.This research contributes to the broader goal of embedding sustainability principles within the educational framework, fostering a generation of professionals equipped with the knowledge and skills necessary to address environmental challenges.

Rafiq Ullah, Amjad Mehmood, Muhammad Altaf Khan, Insaf Ullah

No abstract is available for this record.

Adrianna E. Lupercio

The urgent call to decarbonize our energy infrastructure, while simultaneously meeting growing energy demands, highlights the need for reliable and clean energy sources. Nuclear energy provides reliable, high-capacity baseload electricity while emitting zero greenhouse gases during operation. To adequately meet the energy needs of society and maintain economic viability, it is crucial to enhance the efficiency of nuclear power plant (NPP) operations. Upgrades to NPP operations require near-term Advanced technology Fuel (ATF), such as doped UO ₂ , to increase the flexibility of plant operation without impacting safety margins. Small additions of metal oxide dopants are reported to increase grain size, thereby limiting fission gas release (FGR) and increasing pellet compliance to mitigate pellet-chemical interactions (PCI) and pellet-cladding mechanical interactions (PCMI). Prior to implementing doped UO ₂ fuels into the reactor fleet, it is important to understand dopant effects on fracture behavior as it impacts fuel performance, such as thermal conductivity, and its tolerance to accident conditions. The availability of fracture data for irradiated and unirradiated UO ₂ is limited, while only one study (N = 7, where N is the number of test samples) is available for unirradiated doped UO ₂ . Hence, a knowledge-gap exists in the literature for fracture behavior of doped UO ₂ fuel forms. The existing knowledge-gap in fuel fracture analysis partly stems from the inherent challenges in machining radiological materials into samples suitable for the traditional bend bar tests. Consequently, acquiring sufficient data to understand the stochastic fracture behavior of ceramic materials is difficult. The ball-on-ring (BOR) biaxial flexure test method utilizes simple right cylindrical geometries representative of commercial nuclear fuel, requires minimal surface preparation, and is tolerant of edge defects; these advantages reduce the time and cost of sample production. As a full understanding of the statistical fracture behavior for ATF concepts has not been established, this work aims to develop and establish the BOR test method to obtain statistical fracture data of undoped and doped UO ₂ , providing insight into fracture behavior. Chapter two of this work presents a study performed to validate the BOR biaxial flexure technique using technical ceramics with well-known mechanical properties complemented with finite element analysis (FEA). Chapter three details a test case of CeO ₂ and Ti-doped CeO ₂ to obtain statistical fracture data. The CeO ₂ material was selected as a surrogate for UO ₂ to refine sample processing, characterization techniques, and the BOR test method for undoped and doped UO ₂ . The research study performed on CeO ₂ and Ti-doped CeO ₂ was motivated by its use as an electrolyte material for intermediate temperature solid oxide fuel cells (IT-SOFCs). The Ti-CeO ₂ samples were doped with 0.1 weight percent (wt%) TiO ₂ and resulted in an increased characteristic strength (≈ 20%) and Weibull modulus compared to CeO ₂ , making them a more robust option for IT-SOFCs. In the context of this collective study, it was intended to provide proof of concept for the BOR test method for the testing of UO ₂ . Chapter four details the work to produce a benchmark dataset to establish the fracture behavior of undoped UO ₂ using the BOR method. This work provides a robust dataset for a comparative analysis of the fracture behavior of doped UO ₂ and future fracture studies of ATF concepts. Hertzian contact damage was observed for undoped UO ₂ test batch 1 due to the small diameter loading ball (≈ 3 mm), which was no longer observed in test batch 2 with a larger loading ball (≈ 19 mm). The contact damage did not appear to influence fracture behavior as both datasets resulted in a characteristic strength and Weibull modulus that agrees with previously published transverse rupture strength (TRS) values for undoped UO ₂ . In chapter five, the statistical fracture of doped UO ₂ was acquired for UO ₂ doped with TiO ₂ or Cr ₂ O ₃ to investigate the effects of dopants on the fracture behavior of UO ₂ . The interplay among grain size, dopant-induced defect structures, and pore size and distribution were explored. Both TiO ₂ and Cr ₂ O ₃ doped UO ₂ sample sets resulted in lattice contraction and a characteristic strength and Weibull modulus that were lower than expected based on density, pore size, and distribution. The increased grain size of TiO ₂ doped UO ₂ samples was expected to reduce the fracture strength, yet residual tensile stresses attributed to dopant incorporation in the UO ₂ lattice had a greater impact on fracture behavior. Doped UO ₂ samples resulted in a reduced fracture strength and with a larger scatter in TRS values. Collectively, the body of this work establishes a BOR test method for the rapid fabrication and mechanical testing of UO ₂ and ATF concepts and presented a comparative analysis of fracture behavior for undoped and doped UO ₂ fuels. The statistical fracture data presented in this study provide baseline data for enhanced fuel performance code predictions of fuel fracture behavior impacting phenomena during reactor operation. This work provides foundational analysis of fracture behavior to advance research on ATF concepts and assist in acceleration of fuel qualification for the current and future nuclear reactor fleets.

Cansu Betin Onur

In this study, we introduce a novel zero-knowledge identification scheme based on the hardness of the subgroup distance problem in the Hamming metric. The proposed protocol, named Subgroup Distance Zero Knowledge Proof (SDZKP), employs a cryptographically secure pseudorandom number generator to mask secrets and utilizes a Stern-type algorithm to ensure robust security properties.

Ryan Lavin, Xuekai Liu, Hardhik Mohanty, L. E. J. Norman · 6 authors

Zero-knowledge proofs (ZKPs) enable computational integrity and privacy by allowing one party to prove the truth of a statement without revealing underlying data. Compared with alternatives such as homomorphic encryption and secure multiparty computation, ZKPs offer distinct advantages in universality and minimal trust assumptions, with applications spanning blockchain systems and confidential verification of computational tasks. This survey provides a technical overview of ZKPs with a focus on an increasingly relevant subset called zkSNARKs. Unlike prior surveys emphasizing algorithmic and theoretical aspects, we take a broader view of practical deployments and recent use cases across multiple domains including blockchain privacy, scaling, storage, and interoperability, as well as non-blockchain applications such as voting, authentication, timelocks, and machine learning. To support consistent comparison, we provide (i) a taxonomy of application areas, (ii) evaluation criteria including proof size, prover and verifier time, memory, and setup assumptions, and (iii) comparative tables summarizing key tradeoffs and representative systems. The survey also covers supporting infrastructure, including zero-knowledge virtual machines, domain-specific languages, libraries, and frameworks. While emphasizing zkSNARKs for their prevalence in deployed systems, we compare them with zkSTARKs and Bulletproofs to clarify transparency and performance tradeoffs. We conclude with future research and application directions.

Komala Rangappa, Arun Kumar Banavara Ramaswamy, Mahadeshwara Prasad, Shreyas Arun Kumar

In the era of cloud computing, guaranteeing the safety and effectiveness of data management is of utmost importance. This investigation presents a novel approach that amalgamates the sharding concept, encryption, zero-knowledge proofs (zkp), and blockchain technology for secure data retrieval and data access control to improve data security, efficiency in cloud storage and migration. Further, we utilize user-specific digital wallets for secure encryption keys in order to encrypt the file before storing into the cloud. As Large files (greater than 50 MB) or Big data files (greater than 1 TB) require greater computational complexity, we leverage the sharding concept to enhance both space and time complexity in cloud storage. Hence, the large files are divided into shards and stored in different database servers. We also employ a blockchain smart contract to enhance secure retrieval of the file and also a secure access method, which ensures the privacy of the user. The zk-snark protocol is utilized to ensure the safe transfer of data between different cloud services. By utilizing this approach, data privacy is preserved, as only the proof of the data’s authenticity is shared with the verifier at the destination cloud, rather than the actual data themselves. The suggested method tackles important concerns related to data protection, privacy, and efficient resource utilization in cloud computing settings by ensuring it meets all the cloud policies required to store data. Since the environment maintains the privacy of the user data and the raw data of the user is not stored anywhere, the entire environment is set up as a Zero trust model.

Kyohei Shibano, Kensuke Ito, Changhee Han, Tsz Tat Chu · 6 authors

In this study, a new data-sharing method is proposed that uses a private InterPlanetary File System—a decentralized storage system operated within a closed network—to distribute data to external entities while making its authenticity verifiable. Among the two operational modes of IPFS, public and private, this study focuses on the method for using private IPFS. Private IPFS is not open to the general public; although it poses a risk of data tampering when distributing data to external parties, the proposed method ensures the authenticity of the received data. In particular, this method applies a type of zero-knowledge proof, namely, the Groth16 protocol of zk-SNARKs, to ensure that the data corresponds to the content identifier in a private IPFS. Moreover, the recipient’s name is embedded into the distributed data to prevent unauthorized secondary distribution. Experiments confirmed the effectiveness of the proposed method for an image data size of up to 120 × 120 pixels. In future studies, the proposed method will be applied to larger and more diverse data types.

Kyosuke Hatsugai, Suthee Ruangwises, Kyoichi Asano, Yoshiki Abe

Abstract Sumplete is a logic puzzle generated by ChatGPT in March 2023. The puzzle consists of a rectangular grid, with each cell containing an integer. Each row and column also has an integer called target value assigned to it. The objective of this puzzle is to cross out some numbers in the grid such that the sum of uncrossed numbers in each row and column is equal to the corresponding target value. In this paper, we prove that Sumplete is NP-complete. We also propose a physical zero-knowledge proof protocol for the puzzle using physical cards.

Chenfei Nie, Yannan Li, Yuxin Yang, Yuede Ji · 5 authors

Federated learning (FL) is an emerging distributed learning paradigm without sharing participating clients' private data. However, existing works show that FL is vulnerable to both Byzantine (security) attacks and data reconstruction (privacy) attacks. Almost all the existing FL defenses only address one of the two attacks. A few defenses address the two attacks, but they are not efficient and effective enough. We propose BPFL, an efficient Byzantine-robust and provably privacy-preserving FL method that addresses all the issues. Specifically, we draw on state-of-the-art Byzantine-robust FL methods and use similarity metrics to measure the robustness of each participating client in FL. The validity of clients are formulated as circuit constraints on similarity metrics and verified via a zero-knowledge proof. Moreover, the client models are masked by a shared random vector, which is generated based on homomorphic encryption. In doing so, the server receives the masked client models rather than the true ones, which are proven to be private. BPFL is also efficient due to the usage of non-interactive zero-knowledge proof. Experimental results on various datasets show that our BPFL is efficient, Byzantine-robust, and privacy-preserving.

Guiyou Wang, Chao Li, Bingrong Dai, Shaohua Zhang

This study proposes an privacy-protection method for blockchain transactions based on lightweight homomorphic encryption, aiming to ensure the security of transaction data and user privacy, and improve transaction efficiency. We have built a blockchain infrastructure and, based on its structural characteristics, adopted zero-knowledge proof technology to verify the legitimacy of data, ensuring the authenticity and accuracy of transactions from the application end to the smart-contract end. On this basis, the Paillier algorithm is used for key generation, encryption, and decryption, and intelligent protection of blockchain transaction privacy is achieved through a secondary encryption mechanism. The experimental results show that this method performs well in privacy and security protection, with a data leakage probability as low as 2.8%, and can effectively defend against replay attacks and forged-transaction attacks. The degree of confusion remains above 0.9, with small fluctuations and short running time under different key lengths and moderate CPU usage, achieving lightweight homomorphic encryption. This not only ensures the security and privacy of transaction data in blockchain networks, but also reduces computational complexity and resource consumption, better adapting to the high-concurrency and low-latency characteristics of blockchain networks, thereby ensuring the efficiency and real-time performance of transactions.

Change Institutions to: University of Waterloo, Yue Zhao, Claudio Angione, Harry Yang · 8 authors

The rapid advancement of ML models in critical sectors such as healthcare, finance, and security has intensified the need for robust data security, model integrity, and reliable outputs. Large multimodal foundational models, while crucial for complex tasks, present challenges in scalability, reliability, and potential misuse. Decentralized systems offer a solution by distributing workload and mitigating central points of failure, but they introduce risks of unauthorized access to sensitive data across nodes. We address these challenges with a comprehensive framework designed for responsible AI development. Our approach incorporates: 1) Zero-knowledge proofs for secure model verification, enhancing trust without compromising privacy. 2) Consensus-based verification checks to ensure consistent outputs across nodes, mitigating hallucinations and maintaining model integrity. 3) Split Learning techniques that segment models across different nodes, preserving data privacy by preventing full data access at any point. 4) Hardware-based security through trusted execution environments (TEEs) to protect data and computations. This framework aims to enhance security and privacy and improve the reliability and fairness of multimodal AI systems. Promoting efficient resource utilization contributes to more sustainable AI development. Our state-of-the-art proofs and principles demonstrate the framework's effectiveness in responsibly democratizing artificial intelligence, offering a promising approach for building secure and private foundational models.

Mohammed Alghazwi, Tariq Bontekoe, Leon Visscher, Fatih Türkmen

Abstract Non-interactive zero-knowledge (NIZK) proofs of knowledge have proven to be highly relevant for securely realizing a wide array of applications that rely on both privacy and correctness . They enable a prover to convince any party of the correctness of a public statement for a secret witness . However, most NIZKs do not natively support proving knowledge of a secret witness that is distributed over multiple provers. Previously, collaborative proofs [54] have been proposed to overcome this limitation. We investigate the notion of composability in this setting, following the Commit-and-Prove design of LegoSNARK [19]. Composability allows users to combine different, specialized NIZKs (e.g., one for arithmetic circuits, one for boolean circuits, and one for range proofs) with the aim of reducing the proof generation time. Moreover, it opens the door to efficient realizations of many applications in the collaborative setting such as mutually exclusive prover groups, combining collaborative and single-party proofs and efficiently implementing publicly auditable secure multiparty computing (PA-MPC). We present the first, general definition for collaborative commitand- prove NIZK (CP-NIZK) proofs of knowledge and construct MPC protocols to enable their realization. We implement our protocols for two commonly used NIZKs, Groth16 and Bulletproofs, and evaluate their practicality in a variety of computational settings. Our findings indicate that composability adds only minor overhead, especially for large circuits. We also evaluated our construction in two application settings, one of which shows 18– $$55\times $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mn>55</mml:mn> <mml:mo>×</mml:mo> </mml:mrow> </mml:math> runtime reduction when compared to prior works while requiring only a fraction ( $$0.2\%$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mn>0.2</mml:mn> <mml:mo>%</mml:mo> </mml:mrow> </mml:math> ) of the communication.

Haonan Wang, Jingyu Wang, Lixin Liu, Yu Lu

No abstract is available for this record.

Annu

Modern cryptography relies heavily on the principles of algebraic structures to ensure the security and integrity of data. This paper explores the fundamental algebraic structures that underpin contemporary cryptographic systems, including groups, rings, fields, and lattices. We provide a detailed examination of how these structures are employed in various cryptographic algorithms and protocols, such as public-key cryptography, digital signatures, and hash functions. an overview of basic algebraic concepts and their properties, followed by an in-depth analysis of their applications in cryptographic schemes. For instance, the use of elliptic curve groups in Elliptic Curve Cryptography (ECC) offers enhanced security with smaller key sizes compared to traditional systems like RSA. Similarly, lattice-based cryptography presents promising solutions for post-quantum security, leveraging the hardness of lattice problems to resist attacks by quantum computers. the role of algebraic structures in the development of advanced cryptographic techniques, such as homomorphic encryption, which allows computations on encrypted data without decryption, and zero-knowledge proofs, which enable the verification of information without revealing the information itself. Through these examples, we illustrate the critical importance of algebraic structures in achieving robust and efficient cryptographic systems.

Jingcheng Zhang, Yingxuan Ren, Man Ho Au, Ka-Ho Chow · 9 authors

Abstract With the rapid developments in sequencing technologies, individuals now have unprecedented access to their genomic data. However, existing data management systems or protocols are inadequate for protecting privacy, limiting individuals’ control over their genomic information, hindering data sharing, and posing a challenge for biomedical research. To fill the gap, an owner-governed system that fulfills owner authority, lifecycle data encryption, and verifiability at the same time is prompted. In this paper, we realized Governome, an owner-governed data management system designed to empower individuals with absolute control over their genomic data during data sharing. Governome uses a blockchain to manage all transactions and permissions, enabling data owners with dynamic permission management and to be fully informed about every data usage. It uses homomorphic encryption and zero-knowledge proofs to enable genomic data storage and computation in an encrypted and verifiable form for its whole lifecycle. Governome supports genomic analysis tasks, including individual variant query, cohort study, GWAS analysis, and forensics. Query of a variant’s genotype distribution among 2,504 1kGP individuals in Governome can be efficiently completed in under 18 hours on an ordinary server. Governome is an open-source project available at https://github.com/HKU-BAL/Governome .

Milan Feltovic

This article explores the transformative potential of blockchain technology in police operations, focusing on enhancing security, transparency, and efficiency. Initially recognized for its role in cryptocurrencies, blockchain's inherent immutability and distributed ledger features are now being leveraged to revolutionize data management within law enforcement. The technology ensures the secure, auditable, and tamper-resistant recording of all transactions and data related to police operations, from investigation records to evidence management, ensuring accessibility only to authorized personnel. Key areas examined include the enhancement of security and transparency through blockchain's immutable and distributed records, ensuring data integrity and evidence management by providing an unalterable record of all transactions and data, and improving interoperability among various police departments and agencies. The integration of advanced technologies like Zero-Knowledge Proofs and Layer 2 solutions further strengthens privacy protection and operational speed, contributing to a more efficient and reliable police information system. Practical implementations in police departments worldwide, such as Delhi Police's blockchain initiative for evidence tracking and Dubai Police's collaboration with Cardano Blockchain for secure data sharing, demonstrate significant improvements in transparency, integrity, and security of processes. The article concludes by addressing the ongoing challenges of scalability, interoperability, and privacy, emphasizing the need for continued development and standardization to fully realize blockchain's benefits in modernizing police operations. By evaluating these aspects, the article highlights blockchain's critical role in the digital transformation of law enforcement, promoting greater public trust and cooperation among police units at both national and international levels.