The rapid evolution of quantum computing poses significant threats to traditional cryptographic schemes,particularly in Decentralized Finance(DeFi)systems that rely on legacy mechanisms like RSA and ECDSA for digital ...The rapid evolution of quantum computing poses significant threats to traditional cryptographic schemes,particularly in Decentralized Finance(DeFi)systems that rely on legacy mechanisms like RSA and ECDSA for digital identity verification.This paper proposes a quantum-resilient,blockchain-based identity verification framework designed to address critical challenges in privacy preservation,scalability,and post-quantum security.The proposed model integrates Post-quantum Cryptography(PQC),specifically lattice-based cryptographic primitives,with Decentralized Identifiers(DIDs)and Zero-knowledge Proofs(ZKPs)to ensure verifiability,anonymity,and resistance to quantum attacks.A dual-layer architecture is introduced,comprising an identity layer for credential generation and validation,and an application layer for DeFi protocol integration.To evaluate its performance,the framework is tested on multiple real-world DeFi platforms using metrics such as verification latency,throughput,attack resistance,energy efficiency,and quantum attack simulation.The results demonstrate that the proposed framework achieves 90%latency reduction and over 35%throughput improvement compared to traditional blockchain identity solutions.It also exhibits a high quantum resistance score(95/100),with successful secure verification under simulated quantum adversaries.The revocation mechanism—implemented using Merkle-tree-based proofs—achieves average response times under 40 ms,and the system maintains secure operations with energy consumption below 9 J per authentication cycle.Additionally,the paper presents a security and cost tradeoff analysis using ZKP schemes such as Bulletproofs and STARKs,revealing superior bits-per-byte efficiency and reduced proof sizes.Real-world adoption scenarios,including integration with six major DeFi protocols,indicate a 25%increase in verified users and a 15%improvement in Total Value Locked(TVL).The proposed solution is projected to remain secure until 2041(basic version)and 2043(advanced version),ensuring long-term sustainability and future-proofing against evolving quantum threats.This work establishes a scalable,privacy-preserving identity model that aligns with emerging post-quantum security standards for decentralized ecosystems.展开更多
Decentralized finance(DeFi)is a general term for a series of financial products and services.It is based on blockchain technology and has attracted people’s attention because of its open,transparent,and intermediary ...Decentralized finance(DeFi)is a general term for a series of financial products and services.It is based on blockchain technology and has attracted people’s attention because of its open,transparent,and intermediary free.Among them,the DeFi ecosystem based on Ethereum-based blockchains attracts the most attention.However,the current decentralized financial system built on the Ethereum architecture has been exposed to many smart contract vulnerabilities during the last few years.Herein,we believe it is time to improve the understanding of the prevailing Ethereum-based DeFi ecosystem security issues.To that end,we investigate the Ethereum-based DeFi security issues:1)inherited from the real-world financial system,which can be solved by macro-control;2)induced by the problems of blockchain architecture,which require a better blockchain platform;3)caused by DeFi invented applications,which should be focused on during the project development.Based on that,we further discuss the current solutions and potential directions ofDeFi security.According to our research,we could provide a comprehensive vision to the research community for the improvement of Ethereum-basedDeFi ecosystem security.展开更多
Decentralized Finance(DeFi)is a system of financial products and services built and delivered through smart contracts on various blockchains.In recent years,DeFi has gained popularity and market capitalization.However...Decentralized Finance(DeFi)is a system of financial products and services built and delivered through smart contracts on various blockchains.In recent years,DeFi has gained popularity and market capitalization.However,it has also been connected to crime,particularly various types of securities violations.The lack of Know Your Customer requirements in DeFi poses challenges for governments trying to mitigate potential offenses.This study aims to determine whether this problem is suited to a machine learning approach,namely,whether we can identify DeFi projects potentially engaging in securities violations based on their tokens’smart contract code.We adapted prior works on detecting specific types of securities violations across Ethereum by building classifiers based on features extracted from DeFi projects’tokens’smart contract code(specifically,opcode-based features).Our final model was a random forest model that achieved an 80%F-1 score against a baseline of 50%.Notably,we further explored the code-based features that are the most important to our model’s performance in more detail by analyzing tokens’Solidity code and conducting cosine similarity analyses.We found that one element of the code that our opcode-based features can capture is the implementation of the SafeMath library,although this does not account for the entirety of our features.Another contribution of our study is a new dataset,comprising(a)a verified ground truth dataset for tokens involved in securities violations and(b)a set of legitimate tokens from a reputable DeFi aggregator.This paper further discusses the potential use of a model like ours by prosecutors in enforcement efforts and connects it to a wider legal context.展开更多
This study examines blockchain technologies and their pivotal role in the evolving Metaverse,shedding light on topics such as how to invest in cryptocurrency,the mechanics behind crypto mining,and strategies to effect...This study examines blockchain technologies and their pivotal role in the evolving Metaverse,shedding light on topics such as how to invest in cryptocurrency,the mechanics behind crypto mining,and strategies to effectively buy and trade cryptocurrencies.While it contextualises the common queries of"why is crypto crashing?"and"why is crypto down?",the research transcends beyond the frequent market fluctuations to unravel how cryptocurrencies fundamentally work and the step-by-step process on how to create a cryptocurrency.Contrasting existing literature,this comprehensive investigation encompasses both the economic and cybersecurity risks inherent in the blockchain and fintech spheres.Through an interdisciplinary approach,the research transitions from the fundamental principles of fintech investment strategies to the overarching implications of blockchain within the Metaverse.Alongside exploring machine learning potentials in financial sectors and risk assessment methodologies,the study critically assesses whether developed or developing nations are poised to reap greater benefits from these technologies.Moreover,it probes into both enduring and dubious crypto projects,drawing a distinct line between genuine blockchain applications and Ponzi-like schemes.The conclusion resolutely affirms the staying power of blockchain technologies,underlined by a profound exploration of their intrinsic value and a reflective commentary by the author on the potential risks confronting individual investors.展开更多
This study examines the link between stocks and decentralized finance(DeFi)in terms of returns and volatility.Major G7 exchange-traded funds(ETFs)and various highly traded DeFi assets are considered to ensure the robu...This study examines the link between stocks and decentralized finance(DeFi)in terms of returns and volatility.Major G7 exchange-traded funds(ETFs)and various highly traded DeFi assets are considered to ensure the robustness of the empirical experiment.Specifically,this study applies the vector autoregression generalized autoregressive conditional heteroskedasticity(VAR-GARCH)model to examine the information transmission of these two markets on a two-way basis and the dynamic conditional correlation(DCC)-GARCH model to assess the bivariate correlation structure between each DeFi and ETF pair.The volatility spillover analysis proves a contagion effect occurred between different geographic markets,and even between markets of different natures and typologies,during the most turbulent moments of the COVID-19 crisis and the war in the Ukraine.Our results also reveal a weak positive correlation between most DeFi and ETF pairs and positive hedge ratios that approach unity during turbulent times.In addition,DeFi assets,except for the Bazaar(BZR)Protocol,can offer diversification gains when included in financial investment portfolios.These results are particularly relevant for portfolio managers and policy-makers when designing investment strategies,especially during periods of financial crisis.展开更多
BACKGROUND:Automated external defibrillators(AEDs)enable laypeople to provide early defi brillations to patients undergoing cardiac arrest,but scant information is available on the general public’s ability to use AED...BACKGROUND:Automated external defibrillators(AEDs)enable laypeople to provide early defi brillations to patients undergoing cardiac arrest,but scant information is available on the general public’s ability to use AEDs.This study assessed the ability of laypeople to operate AEDs,the effect of a 15-minute training,and whether skills differed by age.METHODS:From May 1 to December 31,2018,a prospective simulation study was conducted with 94 laypeople aged 18–65 years(32 aged 18–24 years,34 aged 25–54 years,and 28 aged 55–65 years)with no prior AED training.The participants’AED skills were assessed individually pretraining,post-training,and at a three-month follow-up using a simulated cardiac arrest scenario.The critical actions and time intervals were evaluated during the AED operating process.RESULTS:Only 14(14.9%)participants(eight aged 18–24 years,four aged 25–54 years,and two aged 55–65 years)successfully delivered defi brillations before training.AED operation errors were more likely to occur among the participants aged 55–65 years than among other age groups.After training,the proportion of successful defi brillations increased signifi cantly(18–24 years old:25.0%vs.71.9%,P<0.01;25–54 years old:11.8%vs.70.6%,P<0.01;55–65 years old:7.1%vs.67.9%,P<0.01).After three months,26.1%of the participants aged 55–65 years successfully delivered defi brillations,which was signifi cantly lower than that of participants aged 18–24 years(54.8%)and 25–54 years(64.3%)(P=0.02).There were no differences in time measures among three age groups in each test.CONCLUSIONS:The majority of untrained laypeople cannot effectively operate AEDs.More frequent training and refresher courses are crucial to improve AED skills.展开更多
Recent advancements in decentralized finance(DeFi)have resulted in a rapid increase in the use of Automated Market Makers(AMMs)for creating decentralized exchanges(DEXs).In this paper,we organize these developments by...Recent advancements in decentralized finance(DeFi)have resulted in a rapid increase in the use of Automated Market Makers(AMMs)for creating decentralized exchanges(DEXs).In this paper,we organize these developments by treating an AMM as a neoclassical black-box characterized by the conversion of inputs(tokens)to outputs(prices).The conversion is governed by the technology of the AMM summarized by an‘exchange function’.Various types of AMMs are examined,including:Constant Product Market Makers;Constant Mean Market Makers;Constant Sum Market Makers;Hybrid Function Market Makers;and,Dynamic Automated Market Makers.The paper also looks at the impact of introducing concentrated liquidity in an AMM.Overall,the framework presented here provides an intuitive geometric representation of how an AMM operates,and a clear delineation of the similarities and differences across the various types of AMMs.展开更多
Ports play a fundamental role in a sustainable integration of Africa in International trade. Both importers and exporters, shipping companies and government, however face high cost for sea transport and substantial in...Ports play a fundamental role in a sustainable integration of Africa in International trade. Both importers and exporters, shipping companies and government, however face high cost for sea transport and substantial inefficiency in port operations. This has resulted in congestion, higher dwell time, higher costs which affect the competitive ability in sub regional and global economy. This study investigates the main factors explaining poor container handling operations and limited competitive ability in Cameroonian Ports and aggregating this to the competitive position of Cameroonian ports in the West and Central African sub-regions (WCA). Using Analytic Hierarchy Process (A.H.P), the paper seeks to provide a basic understanding of container transportation and port’s terminal operations problems (constraints & ineffectiveness) in Cameroon.展开更多
Nowadays,tungsten oxides,as a typical transition metal oxide,are widely and intensively investigated owing to their excellent material properties and device properties.Controlling oxygen defi ciency in tungsten oxides...Nowadays,tungsten oxides,as a typical transition metal oxide,are widely and intensively investigated owing to their excellent material properties and device properties.Controlling oxygen defi ciency in tungsten oxides is typically the key to enhance their performances for a variety of critical technological applications.With a gradual increase of oxygen defi ciency,various non-stoichiometric tungsten oxides can be formed by re-adjustment of the atomic arrangement,which exhibits superior performances than their traditional stoichiometric counterparts.This review mainly focuses on the recent advances in oxygen-defi cient tungsten oxides from the point of atomic structures,including the forming mechanism of non-stoichiometric tungsten oxides and the superiority of these oxygen-defi cient tungsten oxides in energy-related devices.Finally,the challenge and perspective of oxygen-defi cient tungsten oxides are also discussed.展开更多
文摘The rapid evolution of quantum computing poses significant threats to traditional cryptographic schemes,particularly in Decentralized Finance(DeFi)systems that rely on legacy mechanisms like RSA and ECDSA for digital identity verification.This paper proposes a quantum-resilient,blockchain-based identity verification framework designed to address critical challenges in privacy preservation,scalability,and post-quantum security.The proposed model integrates Post-quantum Cryptography(PQC),specifically lattice-based cryptographic primitives,with Decentralized Identifiers(DIDs)and Zero-knowledge Proofs(ZKPs)to ensure verifiability,anonymity,and resistance to quantum attacks.A dual-layer architecture is introduced,comprising an identity layer for credential generation and validation,and an application layer for DeFi protocol integration.To evaluate its performance,the framework is tested on multiple real-world DeFi platforms using metrics such as verification latency,throughput,attack resistance,energy efficiency,and quantum attack simulation.The results demonstrate that the proposed framework achieves 90%latency reduction and over 35%throughput improvement compared to traditional blockchain identity solutions.It also exhibits a high quantum resistance score(95/100),with successful secure verification under simulated quantum adversaries.The revocation mechanism—implemented using Merkle-tree-based proofs—achieves average response times under 40 ms,and the system maintains secure operations with energy consumption below 9 J per authentication cycle.Additionally,the paper presents a security and cost tradeoff analysis using ZKP schemes such as Bulletproofs and STARKs,revealing superior bits-per-byte efficiency and reduced proof sizes.Real-world adoption scenarios,including integration with six major DeFi protocols,indicate a 25%increase in verified users and a 15%improvement in Total Value Locked(TVL).The proposed solution is projected to remain secure until 2041(basic version)and 2043(advanced version),ensuring long-term sustainability and future-proofing against evolving quantum threats.This work establishes a scalable,privacy-preserving identity model that aligns with emerging post-quantum security standards for decentralized ecosystems.
基金supported by the Key-Area Research and Development Program of Guangdong Province 2020B0101090003CCF-NSFOCUS Kunpeng Scientific Research Fund (CCFNSFOCUS 2021010)+4 种基金Innovation Fund Program of the Engineering Research Center for Integration and Application of Digital Learning Technology of Ministry of Education under Grant No.1221027National Natural Science Foundation of China (Grant Nos.61902083,62172115,61976064)Guangdong Higher Education Innovation Group 2020KCXTD007 and Guangzhou Higher Education Innovation Group (No.202032854)Guangzhou Fundamental Research Plan of“Municipal-School”Jointly Funded Projects (No.202102010445)Guangdong Province Science and Technology Planning Project (No.2020A1414010370).
文摘Decentralized finance(DeFi)is a general term for a series of financial products and services.It is based on blockchain technology and has attracted people’s attention because of its open,transparent,and intermediary free.Among them,the DeFi ecosystem based on Ethereum-based blockchains attracts the most attention.However,the current decentralized financial system built on the Ethereum architecture has been exposed to many smart contract vulnerabilities during the last few years.Herein,we believe it is time to improve the understanding of the prevailing Ethereum-based DeFi ecosystem security issues.To that end,we investigate the Ethereum-based DeFi security issues:1)inherited from the real-world financial system,which can be solved by macro-control;2)induced by the problems of blockchain architecture,which require a better blockchain platform;3)caused by DeFi invented applications,which should be focused on during the project development.Based on that,we further discuss the current solutions and potential directions ofDeFi security.According to our research,we could provide a comprehensive vision to the research community for the improvement of Ethereum-basedDeFi ecosystem security.
基金funded by the UK EPSRC grant EP/S022503/1 that supports the Centre for Doctoral Training in Cybersecurity at UCL.
文摘Decentralized Finance(DeFi)is a system of financial products and services built and delivered through smart contracts on various blockchains.In recent years,DeFi has gained popularity and market capitalization.However,it has also been connected to crime,particularly various types of securities violations.The lack of Know Your Customer requirements in DeFi poses challenges for governments trying to mitigate potential offenses.This study aims to determine whether this problem is suited to a machine learning approach,namely,whether we can identify DeFi projects potentially engaging in securities violations based on their tokens’smart contract code.We adapted prior works on detecting specific types of securities violations across Ethereum by building classifiers based on features extracted from DeFi projects’tokens’smart contract code(specifically,opcode-based features).Our final model was a random forest model that achieved an 80%F-1 score against a baseline of 50%.Notably,we further explored the code-based features that are the most important to our model’s performance in more detail by analyzing tokens’Solidity code and conducting cosine similarity analyses.We found that one element of the code that our opcode-based features can capture is the implementation of the SafeMath library,although this does not account for the entirety of our features.Another contribution of our study is a new dataset,comprising(a)a verified ground truth dataset for tokens involved in securities violations and(b)a set of legitimate tokens from a reputable DeFi aggregator.This paper further discusses the potential use of a model like ours by prosecutors in enforcement efforts and connects it to a wider legal context.
基金supported by the PETRAS National Centre of Excellence for IoT Systems Cybersecurity,which has been funded by the UK EPSRC[under grant number EP/S035362/1]the Software Sustainability Institute[grant number:EP/S021779/1]by the Cisco Research Centre[grant number CG1525381].
文摘This study examines blockchain technologies and their pivotal role in the evolving Metaverse,shedding light on topics such as how to invest in cryptocurrency,the mechanics behind crypto mining,and strategies to effectively buy and trade cryptocurrencies.While it contextualises the common queries of"why is crypto crashing?"and"why is crypto down?",the research transcends beyond the frequent market fluctuations to unravel how cryptocurrencies fundamentally work and the step-by-step process on how to create a cryptocurrency.Contrasting existing literature,this comprehensive investigation encompasses both the economic and cybersecurity risks inherent in the blockchain and fintech spheres.Through an interdisciplinary approach,the research transitions from the fundamental principles of fintech investment strategies to the overarching implications of blockchain within the Metaverse.Alongside exploring machine learning potentials in financial sectors and risk assessment methodologies,the study critically assesses whether developed or developing nations are poised to reap greater benefits from these technologies.Moreover,it probes into both enduring and dubious crypto projects,drawing a distinct line between genuine blockchain applications and Ponzi-like schemes.The conclusion resolutely affirms the staying power of blockchain technologies,underlined by a profound exploration of their intrinsic value and a reflective commentary by the author on the potential risks confronting individual investors.
基金supported by Ministerio de Ciencia e Innovacion(PID2021-128829NB-100)funded by MCIN/AEI/10.13039/501100011033+1 种基金by"ERDF A way of making Europe'as wellas the Junta de Comunidades de Castlla-La Mancha(SBPLY/21/180501/000086)the Universidad de Castlla-La Mancha(2022-GRIN-34491),both of which were co-financed with ERDF funds.
文摘This study examines the link between stocks and decentralized finance(DeFi)in terms of returns and volatility.Major G7 exchange-traded funds(ETFs)and various highly traded DeFi assets are considered to ensure the robustness of the empirical experiment.Specifically,this study applies the vector autoregression generalized autoregressive conditional heteroskedasticity(VAR-GARCH)model to examine the information transmission of these two markets on a two-way basis and the dynamic conditional correlation(DCC)-GARCH model to assess the bivariate correlation structure between each DeFi and ETF pair.The volatility spillover analysis proves a contagion effect occurred between different geographic markets,and even between markets of different natures and typologies,during the most turbulent moments of the COVID-19 crisis and the war in the Ukraine.Our results also reveal a weak positive correlation between most DeFi and ETF pairs and positive hedge ratios that approach unity during turbulent times.In addition,DeFi assets,except for the Bazaar(BZR)Protocol,can offer diversification gains when included in financial investment portfolios.These results are particularly relevant for portfolio managers and policy-makers when designing investment strategies,especially during periods of financial crisis.
基金the National Natural Science Foundation of China(81703303)Shanghai Municipal Government Pujiang Research Development Program(17PJC070)+1 种基金HeartRescue Project China Programand Innovative Research Team of High-level Local Universities in Shanghai.
文摘BACKGROUND:Automated external defibrillators(AEDs)enable laypeople to provide early defi brillations to patients undergoing cardiac arrest,but scant information is available on the general public’s ability to use AEDs.This study assessed the ability of laypeople to operate AEDs,the effect of a 15-minute training,and whether skills differed by age.METHODS:From May 1 to December 31,2018,a prospective simulation study was conducted with 94 laypeople aged 18–65 years(32 aged 18–24 years,34 aged 25–54 years,and 28 aged 55–65 years)with no prior AED training.The participants’AED skills were assessed individually pretraining,post-training,and at a three-month follow-up using a simulated cardiac arrest scenario.The critical actions and time intervals were evaluated during the AED operating process.RESULTS:Only 14(14.9%)participants(eight aged 18–24 years,four aged 25–54 years,and two aged 55–65 years)successfully delivered defi brillations before training.AED operation errors were more likely to occur among the participants aged 55–65 years than among other age groups.After training,the proportion of successful defi brillations increased signifi cantly(18–24 years old:25.0%vs.71.9%,P<0.01;25–54 years old:11.8%vs.70.6%,P<0.01;55–65 years old:7.1%vs.67.9%,P<0.01).After three months,26.1%of the participants aged 55–65 years successfully delivered defi brillations,which was signifi cantly lower than that of participants aged 18–24 years(54.8%)and 25–54 years(64.3%)(P=0.02).There were no differences in time measures among three age groups in each test.CONCLUSIONS:The majority of untrained laypeople cannot effectively operate AEDs.More frequent training and refresher courses are crucial to improve AED skills.
文摘Recent advancements in decentralized finance(DeFi)have resulted in a rapid increase in the use of Automated Market Makers(AMMs)for creating decentralized exchanges(DEXs).In this paper,we organize these developments by treating an AMM as a neoclassical black-box characterized by the conversion of inputs(tokens)to outputs(prices).The conversion is governed by the technology of the AMM summarized by an‘exchange function’.Various types of AMMs are examined,including:Constant Product Market Makers;Constant Mean Market Makers;Constant Sum Market Makers;Hybrid Function Market Makers;and,Dynamic Automated Market Makers.The paper also looks at the impact of introducing concentrated liquidity in an AMM.Overall,the framework presented here provides an intuitive geometric representation of how an AMM operates,and a clear delineation of the similarities and differences across the various types of AMMs.
文摘Ports play a fundamental role in a sustainable integration of Africa in International trade. Both importers and exporters, shipping companies and government, however face high cost for sea transport and substantial inefficiency in port operations. This has resulted in congestion, higher dwell time, higher costs which affect the competitive ability in sub regional and global economy. This study investigates the main factors explaining poor container handling operations and limited competitive ability in Cameroonian Ports and aggregating this to the competitive position of Cameroonian ports in the West and Central African sub-regions (WCA). Using Analytic Hierarchy Process (A.H.P), the paper seeks to provide a basic understanding of container transportation and port’s terminal operations problems (constraints & ineffectiveness) in Cameroon.
基金supported by the National Natural Science Foundation of China(No.61904080)the Macao Young Scholars Program of China(No.AM2020005)Guangdong Basic and Applied Basic Research Foundation(No.2022A1515110994).
文摘Nowadays,tungsten oxides,as a typical transition metal oxide,are widely and intensively investigated owing to their excellent material properties and device properties.Controlling oxygen defi ciency in tungsten oxides is typically the key to enhance their performances for a variety of critical technological applications.With a gradual increase of oxygen defi ciency,various non-stoichiometric tungsten oxides can be formed by re-adjustment of the atomic arrangement,which exhibits superior performances than their traditional stoichiometric counterparts.This review mainly focuses on the recent advances in oxygen-defi cient tungsten oxides from the point of atomic structures,including the forming mechanism of non-stoichiometric tungsten oxides and the superiority of these oxygen-defi cient tungsten oxides in energy-related devices.Finally,the challenge and perspective of oxygen-defi cient tungsten oxides are also discussed.
