Nikos Fotiou, Iakovos Pittaras, Vasilios A. Siris, George C. Polyzos · 5 authors
Service providers usually require detailed statistics in order to improve their services. On the other hand, privacy concerns are intensifying and sensitive data is protected by legislation, such as GDPR (General Data Protection Regulation). In this paper, we present the design, implementation, and evaluation of a marketplace that allows “data consumers” to buy information from “data providers”, which can then be used for generating meaningful statistics. Additionally, our system enables “system operators” that can select which data providers are allowed to provide data, based on filtering criteria specified by the data consumer. We leverage local differential privacy to protect the data provider's privacy against data consumers, as well as against system operators, and we build a blockchain-based solution for ensuring fair exchange, and immutable data logs. Our design targets use cases that involve hundreds or even thousands of data providers. We prove the feasibility of our approach through a proof-of concept implementation of a measurement sharing application for smart-grid systems.
Yojna Arora, Mr. Vivek Birla, Mr. Rajat Gupta, Mr. Samarth Tiku
Voting is a constitutional part of governmental systems which gives the people of the nation the liberty to express their opinions. The contemporary system constitutes Electronic Voting Machines (EVM) that is a pile-up of data natively and centralized, making it implausible. Since the data is amassed locally over the EVM(s) prior to the election's cessation, it could be hacked. Furthermore, there have been events of "polling booth hijacking" in some regions during the elections. Ethereum blockchain technology addresses concerns regarding integrity, security, and accessibility of current voting systems. Expanding e-voting into Ethereum based blockchain technology is one potential application of the emerging blockchain technology. This paper presents a decentralized, incognito, and limpid e-voting system named "DILE". It will escalate accessibility as the users could cast their votes without paying a visit to the polling booths. DILE makes practical and effective use of Ethereum's blockchain technology and smart contracts for its implementation.
Open access
Internet Traffic Analysis and Secure E-voting
Blockchain Technology Applications and Security
Advanced Steganography and Watermarking Techniques
Voting is the method of choice used to make a large number of democratic decisions amongst many groups of people. Regardless of whether the method is used in professional or casual scenarios, it provides a fair and efficient way to determine a decision based on the majority. In smaller groups, keeping track of voter decisions is not a difficult task, however, in situations where there are hundreds of thousands of voters, keeping a precise record of voter decisions becomes important and more difficult. The advancements in blockchain technology provide a potential solution to the record-keeping problem of contemporary voting procedures, as blockchain technology by design, excels in applications where multiple users are working on immutable data. In this paper we discuss the design and development of ElectionBlock, a voting system that provides its own blockchain, running on a centralized network of nodes, with the integration of a biometric scanner, to maintain vote integrity and distinguish between registered and unregistered voters. This scheme allows data immutability while providing the user with security and control over their ballot. Experimental results demonstrate the potential for scalability of the system to handle a high volume of votes from multiple servers while maintaining data integrity, performance, and security. This paper will address the considerations taken to develop and implement the centralized and independent blockchain network for use as a voting platform with the integration of biometrics for the purpose of enhanced user security.
Abstract In recent years, blockchain-based systems have emerged powerfully and led to the development of several new and improved applications in terms of increased security, trust, accountability and reliability. One important trust-based application is electronic voting system which still lacks in providing good throughput while also reducing the costs in voting given the deployment of state-of-the-art technologies. So, there is a need to imply an efficient consensus protocol to impart cost-efficiency as well as better performance of a blockchain-based electronic voting system. This paper focuses on boosting up the cost-efficiency in the voting process, while also being auditable, thus, strengthening the trust of voters on the government and lessening the overall costs incurred in voting. In this paper, Proof-of-Stake-Voting is used as consensus protocol which is observed to give a throughput of 4-5K transactions per second. Then its performance is compared with the other existing consensus protocols such as Proof-of-Work and Proof-of-Authority in terms of gas consumption, gas cost, and throughput. It has been shown through the results that there is a significant difference in the total gas cost, with Proof-of-Stake-Voting protocol consuming 3.1 x 10 −7 Ethers (ETH), as compared to the Proof-of-Work, taking 5.42536 x 10 −4 ETH and Proof-of-Authority protocols taking 2.49759 x 10 −4 ETH.
Open access
Blockchain Technology Applications and Security
Internet Traffic Analysis and Secure E-voting
Advanced Steganography and Watermarking Techniques
Situational awareness is essential for a safe and sustainable urban environment. While the wide deployment of Internet of Video Things (IoVT) enables efficient monitoring of the footage of the Smart Cities, it also attracts attackers and abusers. Disinformation injected into the IoVT can mislead the city administrations, policy makers, and emergency responders, and lead to disastrous consequences. It is very challenging to timely authenticate each video stream from pervasively deployed IoVT devices. This article presents a Blockchain Enhanced Video input Authentication (BEVA) scheme as an edge service to fight against the visual layer attacks on smart IoVT systems such as online false video injection and offline video streams tampering attacks. The BEVA scheme leverages the electrical network frequency (ENF) embedded in video recordings as an environmental fingerprint for online false frame detection. Blockchain is integrated to enable a decentralized security networking infrastructure, and it empowers an immutable, traceable, and auditable distributed ledger for ENF-based authentication scheme without relying on a third-party trust authority. This secure-by-design solution efficiently provides trust and secure services in IoVT in modern Smart Cities.
Advanced Steganography and Watermarking Techniques
Matthias Grundmann, Hedwig Amberg, Hannes Hartenstein
Bitcoin is based on a P2P network that is used to propagate transactions and blocks. While the P2P network design intends to hide the topology of the P2P network, information about the topology is required to understand the network from a scientific point of view. Thus, there is a natural tension between the 'desire' for unobservability on the one hand, and for observability on the other hand. On a middle ground, one would at least be interested on some statistical features of the Bitcoin network like the number of peers that participate in the propagation of transactions and blocks. This number is composed of the number of reachable peers that accept incoming connections and unreachable peers that do not accept incoming connections. While the number of reachable peers can be measured, it is inherently difficult to determine the number of unreachable peers. Thus, the number of unreachable peers can only be estimated based on some indicators. In this paper, we first define our understanding of unreachable peers and then propose the PAL (Passive Announcement Listening) method which gives an estimate of the number of unreachable peers by observing ADDR messages that announce active IP addresses in the network. The PAL method allows for detecting unreachable peers that indicate that they provide services useful to the P2P network. In conjunction with previous methods, the PAL method can help to get a better estimate of the number of unreachable peers. We use the PAL method to analyze data from a long-term measurement of the Bitcoin P2P network that gives insights into the development of the number of unreachable peers over five years from 2015 to 2020. Results show that about 31,000 unreachable peers providing useful services were active per day at the end of the year 2020. An empirical validation indicates that the approach finds about 50 % of unreachable peers that provide useful services.
Electing democratic representatives via voting has been a common mechanism since the 17th century. However, these mechanisms raise concerns about fairness, privacy, vote concealment, fair calculations of tally, and proxies voting on their behalf for the voters. Ballot voting, and in recent times, electronic voting via electronic voting machines (EVMs) improves fairness by relying on centralized trust. Homomorphic encryption-based voting protocols also assure fairness but cannot scale to large scale elections such as presidential elections. In this paper, we leverage the blockchain technology of distributing trust to propose a smart contract-based protocol, namely, \proto. There are many existing protocols for voting using smart contracts. We observe that these either are not scalable or leak the vote tally during the voting stage, i.e., do not provide vote concealment. In contrast, we show that FASTEN preserves voter's privacy ensures vote concealment, immutability, and avoids double voting. We prove that the probability of privacy breaches is negligibly small. Further, our cost analysis of executing FASTEN over Ethereum is comparable to most of the existing cost of elections.
This work formalizes Publicly Auditable Conditional Blind Signatures (PACBS), a new cryptographic primitive that allows the verifiable issuance of blind signatures, the validity of which is contingent upon a predicate and decided by a designated verifier. In particular, when a user requests the signing of a message, blinded to protect her privacy, the signer embeds data in the signature that makes it valid if and only if a condition holds. A verifier, identified by a private key, can check the signature and learn the value of the predicate. Auditability mechanisms in the form of non-interactive zero-knowledge proofs are provided, so that a cheating signer cannot issue arbitrary signatures and a cheating verifier cannot ignore the embedded condition. The security properties of this new primitive are defined using cryptographic games. A proof-of-concept construction, based on the Okamoto–Schnorr blind signatures infused with a plaintext equivalence test is presented and its security is analyzed.
In the current work we discuss the notion of gateways as a means for interoperability across different blockchain systems. We discuss two key principles for the design of gateway nodes and scalable gateway protocols, namely (i) the opaque ledgers principle as the analogue of the autonomous systems principle in IP datagram routing, and (ii) the externalization of value principle as the analogue of the end-to-end principle in the Internet architecture. We illustrate the need for a standard gateway protocol by describing a unidirectional asset movement protocol between two peer gateways, under the strict condition of both blockchains being private/permissioned with their ledgers inaccessible to external entities. Several aspects of gateways and the gateway protocol is discussed, including gateway identities, gateway certificates and certificate hierarchies, passive locking transactions by gateways, and the potential use of delegated hash-locks to expand the functionality of gateways.
Cryptocurrencies redefined how money can be stored and transferred among users. However, independent of the amount being sent, public blockchain-based cryptocurrencies suffer from high transaction waiting times and fees. These drawbacks hinder the wide use of cryptocurrencies by masses. To address these challenges, payment channel network concept is touted as the most viable solution to be used for micro-payments. The idea is exchanging the ownership of money by keeping the state of the accounts locally. The users inform the blockchain rarely, which decreases the load on the blockchain. Specifically, payment channel networks can provide transaction approvals in seconds by charging a nominal fee proportional to the payment amount. Such attraction on payment channel networks inspired many recent studies which focus on how to design them and allocate channels such that the transactions will be secure and efficient. However, as payment channel networks are emerging and reaching large number of users, privacy issues are becoming more relevant that raise concerns about exposing not only individual habits but also businesses' revenues. In this paper, we first propose a categorization of the existing payment networks formed on top of blockchain-backed cryptocurrencies. After discussing several emerging attacks on user/business privacy in these payment channel networks, we qualitatively evaluate them based on a number of privacy metrics that relate to our case. Based on the discussions on the strengths and weaknesses of the approaches, we offer possible directions for research for the future of privacy based payment channel networks.
Abstract Election is an important event in all countries. Conventional voting suffers many issues, such as cost of time and efforts needed for tallying and counting results, cost in papers, arrangements and all that it takes for a voting process to be achieved. Many countries such as Australia, Belgium, Brazil, Canada, Estonia, France, Germany, India, Italy, Namibia, the Netherlands, Norway, Peru, Switzerland, the UK, Venezuela and the Philippines considered online e-voting systems, but the traditional e-voting systems suffer a lack of trust, it is not known if a vote is counted correctly, tampered or not. The voter has no guarantee that his/her vote is considered as they voted in elections, it’s a lack of transparency. A solution is e-voting systems based on blockchain (sometimes referred as Distributed Ledger Technology (DLT)) has now turned to be promising for what properties it offer, such as, privacy, security, transparency, accuracy, decentralization in which no central control exist, and most of all, creates an immutable system, where citizens are allowed to vote from their location by using digital devices (smart phones, computers, electronic voting machines). Also, due to the COVID-19 pandemic, many technology applications are heading towards systems with all these properties, at the same time, maintaining social distancing. This review introduced many different ideas for implementing e-voting systems based on Blockchain and how the users (voters and candidates) interact with the system showing the voting process from the first step of registration to authentication till showing the final results. At the end of this review we will illustrate a table that contain all mechanisms used in the papers involved that covers the most important requirements needed for every e-voting system based on blockchain or Distributed Ledger Technology (DLT).
Open access
Internet Traffic Analysis and Secure E-voting
Blockchain Technology Applications and Security
Advanced Steganography and Watermarking Techniques
As the next-generation network architecture, software-defined networking (SDN) has great potential. But how to forward data packets safely is a big challenge today. In SDN, packets are transferred according to flow rules which are made and delivered by the controller. Once flow rules are modified, the packets might be redirected or dropped. According to related research, we believe that the key to forward data flows safely is keeping the consistency of flow rules. However, existing solutions place little emphasis on the safety of flow rules. After summarizing the shortcomings of the existing solutions, we propose FRChain to ensure the security of SDN data forwarding. FRChain is a novel scheme that uses blockchain to secure flow rules in SDN and to detect compromised nodes in the network when the proportion of malicious nodes is less than one-third. The scheme places the flow strategies into blockchain in form of transactions. Once an unmatched flow rule is detected, the system will issue the problem by initiating a vote and possible attacks will be deduced based on the results. To simulate the scheme, we utilize BigchainDB, which has good performance in data processing, to handle transactions. The experimental results show that the scheme is feasible, and the additional overhead for network performance and system performance is less than similar solutions. Overall, FRChain can detect suspicious behaviors and deduce malicious nodes to keep the consistency of flow rules in SDN.
Cryptocurrencies have enhanced financial transactions, but being decentralized, they pose numerous security threats to their users, warranting new anomaly detection systems for fraud prevention.The present research focuses on the machine learning (ML) techniques used in detecting suspicious activities in cryptocurrency networks, focusing on their contribution to AML and CFT compliance.The paper also compares supervised and unsupervised learning techniques and their merits and demerits.The supervised learning techniques, including Decision Trees, SVMs, and Neural Networks, are presented for their accuracy and flexibility, and, on the other hand, the unsupervised learning approaches, including Clustering, Isolation Forests, and Autoencoders are considered for their potential to discover new fraud patterns even if the training data is not labeled.An analysis of the use of explainability tools such as LIME and SHAP in artificial intelligence systems is also carried out to improve how users understand the results given to them by the AI models.These models have their real-life application illustrated by case studies, which prove helpful in identifying anomalies in Bitcoin and Ethereum transactions.New research directions suggest improvements in machine learning methods, the connection of the results with analysis tools based on blockchain, and cooperation with relevant authorities to improve the identification of threats and conformity with established guidelines.The potential of applying the idea of this work in traditional finance and cybersecurity is discussed, highlighting the possibility of applying ML in multiple fields to enhance security and compliance.The study then informs the significance of continued research and collaboration among disciplines to combat the emerging issues of financial fraud and cybercrimes related to cryptocurrencies.
Bilgisayar ve internet teknolojilerindeki gelişmeler, hayatımızın her alanında etkisini gösterdiği gibi ekonomi boyutunda da etkileri yadsınamaz. Ekonomi alanındaki yeni ekonomik reform mahiyetinde kabul gören bu yenilikler FinTek (Finans ve Teknoloji) kapsamı içerisinde yer almaktadır. FinTech inovasyonu ile ekonomide ademi merkeziyetçi bir akım başlatan Bitcoin, şu an dünya ekonomisinde önemli bir yere sahiptir. Bitcoin ile hayatımıza giren Blockchain (Blokzincir) teknolojisinin ise yakın gelecekte hayatımızın vazgeçilmez bir parçası haline geleceği öngörülmektedir. Tüm bu gelişmeler ışığında günümüzün popüler teknolojilerinden olan yapay zeka yöntemlerinden yararlanılarak, kitle haberleşme aracı olarak tanımlanan gazetelerde yer alan, insan ve toplumu ilgilendiren ve toplumun en önemli ihtiyaçlarından olan haberlerin, geleceğin para birimi olarak görülen Bitcoin üzerindeki etkileri ortaya konmak istenmiştir. Bu bağlamda 5 ulusal finans gazetesi belirlenip, Bitcoin’in ilk halka arz yılından itibaren yayınlanan haberleri olumlu ve olumsuz yorum içeriklerine göre sayısallaştırarak, Bitcoin altyapı teknolojisi olan blokzinciri verileri ile ikinci en popüler kripto para olan Ethereum’un ABD dolar karşılığı alınarak, yapay sinir ağları teknikleri ile oluşturulan ağ içerisinde ilişkilendirilmiştir. Çalışma sonucunda %99’luk tahminsel başarı içeren yapay sinir ağında, finansal gazetelerin yayınlamış olduğu Bitcoin içerikli haberlerin, Bitcoin fiyat tahminine güçlü bir etkisinin olmadığı sonucuna varılmıştır. Bunulan birlikte seçilen finansal gazetelerden The Wall Street gazetesinin diğer finansal gazetelere oranla Bitcoin fiyat tahminde nispeten etkisinin olduğu saptanmıştır.
Wide Area Protection System (WAPS) undertakes the important task of maintaining system reliability and stability when the power system is subject to abnormal or predetermined unstable conditions. The existing WAPS adopts a centralized mechanism to record and audit communication messages, which faces the risk of excessive authority and tampering with communication records and audit logs, thus making it impossible to achieve true transparency and fairness. Due to the involvement of multiple parties and equipment maintained by different manufacturers in the communication of WAPS, there are difficulties in tracing the cause of the accident and determining the at-fault party following misoperations and miss trips. To address this issue, we propose a semi-centralized blockchain system with multi-chain for auditing communications of WAPS. We first propose a semi-centralized system architecture according to the system architecture and management requirements of WAPS. Then, we utilize the blockchain network as a self-recording channel to achieve tamper-proof and non-repudiation verification interaction. We also design a multi-chain structure and classification node mechanism to meet the communication auditing requirements of multiple WAPS. We have designed a new block structure that conforms to the communication protocol of WAPS. To reduce the storage burden caused by the ever-expanding blockchain ledger, we propose a deletable blockchain scheme while maintaining the integrity and security of blockchain. Analysis and experiments show that the proposed blockchain system can support the secure, transparent, tamper-proof and traceable communication recording and auditing of WAPS along with high performance.
This article presentsLiteZKPa framework for supporting multiple anonymous payments using a smart contract-based zero-knowledge proof (ZKP) protocol on resource-limited devices. Specifically, to address challenges related to minimizing the computational overhead and offer a fully anonymous system,LiteZKPincludes novel schemes such a new merkle tree mechanism to reduce the burden of ZKP operations, and integrates smart contract-based ZKP with an off-chain payment channel to reduce the amount of ZKP operations when performing continuous data exchange. We present evaluation results ofLiteZKPfrom both PC-scale and resource-limited client devices and our results suggest thatLiteZKPreduces the latency and energy consumption by more than 55% on Internet of Things (IoT)/mobile edge computing platforms, while requiring only 8% of block processing fee compared to a naive ZKP-based scheme.
Beomseok Kim, Woonseob Shin, DongYeop Hwang, Ki‐Hyung Kim
With the development of ICT technology, it has also been applied to the power grid, but as a target of hackers' attack, a security solution to protect the power grid is being studied. Attribute-based Access Control (ABAC) is one of the most commonly used security solutions by providing granular and flexible access control, but it threatens privacy because it determines access control based on user attribute values. With user privacy emerging as a new topic, Decentralized Identity(DID) is emerging as a new alternative for protecting user privacy. In this paper, we propose a DID-based ABAC to solve the problem of ABAC's privacy exposure and apply it to a power transaction platform.
Voting is a complex process with a lot depending on it. Building an e-voting system that can guarantee anonymity, verifiability, and transparency together is a challenging task. Continuous efforts are being made to improve the voting system to achieve these properties. Recently, blockchain has hit the technology space with many promises, especially to make verifiable and transparent decentralized systems. However, a major challenge faced with blockchain-based e-voting systems is to achieve the users' anonymity while ensuring only authorized voters should be able to vote, and that too only once. To address these issues, this paper proposes a blockchain-based e-voting system with secret contracts. We have used Enigma (a secure multiparty computation platform) to design secret contracts. The proposed system meets most of the features required to conduct free and fair voting electronically.
Internet Traffic Analysis and Secure E-voting
Blockchain Technology Applications and Security
Advanced Steganography and Watermarking Techniques
Electronic voting systems have several necessarily requirements, such as anonymity that others cannot link voters with votes, the fairness that votes should not be leaked before the tally, and the accuracy that eligible voters' votes should be counted correctly. There have been proposed various methods to realize the requirements. Some of them require anonymous communication paths as necessary elements to satisfy the anonymity requirement for a practical electronic voting system. Cruz et al. proposed an electronic voting system that does not need anonymous communication paths, using Bitcoin, a cryptographic currency, as a distributed database. However, Bitcoin is a system in which all data are disclosed, and anyone can check what exchanges a person of a certain ID (Bitcoin address) has done. It is possible to reveal which voter made what vote, and hence(anonymity is not satisfied. In this paper, we propose a method to solve the above problem by using Bitcoin mixing. We propose an electronic voting system using Zerocoin, a variant of Bitcoin, as a database, in which zero knowledge proof is used instead of blind signature for mixing.
As the most fundamental infrastructure in the current Internet, the Border Gateway Protocol (BGP) supports the inter-connectivity of different Autonomous Systems (ASs) and then the reachability can be achieved from any network in the Internet. However, due to the lack of security consideration during its original design, the BGP suffers from multiple security threats. Another challenge is that it cannot support the future sophisticated applications with deterministic routing. In this article, we propose a novel BGP management architecture, namely BGPChain, which is based on the blockchain in order to establish a secure, smart, and agile routing infrastructure for the future Internet.
Muhammad Anas Imtiaz, David Starobinski, Ari Trachtenberg, Nabeel Younis
Efficient and reliable propagation of blocks is vital to the scalability of the Bitcoin network. As a result, several schemes, such as the compact block protocol (BIP 152), have been proposed over the last few years to speed up the block propagation. Even so, we provide experimental evidence that (i) the vast majority (97%) of Bitcoin nodes exhibit only intermittent network connectivity (i.e., churn), and (ii) this churn results in significant number of unsuccessful compact blocks, roughly three times the statistic for continuously connected nodes. We conduct experiments on the Bitcoin network that show that churn results in a roughly five fold increase in block propagation time (i.e., 566.89 ms vs. 109.31 ms) on average. To effect our analysis, we develop a statistical model for churn, based on empirical network data, and use this model to actuate live test nodes on the Bitcoin network. The performance of the system is measured within a novel framework that we developed for logging the internal behavior of a Bitcoin node, and which we share for public use. Finally, to mitigate the problem of missing transactions in churning nodes, we propose and implement into Bitcoin Core a new synchronization protocol, dubbed MempoolSync. Our measurements show that churning nodes implementing MempoolSync experience significantly better performance than standard nodes not implementing MempoolSync, including average block propagation delay reduced by over 50%.