In recent decades, several countries have faced political tensions due to citizens' perceptions that their elections are fraudulent; some electors have even chosen not to vote because they believe that the results may be falsified. Thus, electoral fraud is a major issue. E-governance and e-voting are now being used in many countries, some of which are investigating blockchain solutions. The aim of this study is to investigate the potential contributions of blockchain technology to peace on a worldwide level by securing voting systems. Unfortunately, this technology is complex and could potentially generate conflict between actors in elections. Taking an exploratory approach, the authors chose a qualitative method to address this specific topic. Election observers and blockchain experts were interviewed to identify the technology's strengths and weaknesses. Our results emphasize the importance of trust and human factors in the voting process.
Miquel Ferriol-Galmés, Roger Coll Aumatell, Albert Cabellos‐Aparicio, Shoushou Ren · 6 authors
In the inter-domain routing infrastructure, a route leak is defined as a violation of the routing policy agreed between two Autonomous Systems (AS). Route leaks have resulted in large-scale outages on the Internet, taking down several services. Although route leaks seem a simple problem, the solution is complex because: (i) ASes consider -partially- routing policy private, (ii) lack of a formal and standard language to express routing policy and (iii) BGP lacks adequate cryptographic-based security. In this paper, we present an experimental analysis of a distributed ledger-based architecture that provides a solution to route leaks. Specifically, the routing policy is unambiguously expressed using a formal language, that is then stored in a blockchain. This decentralized architecture allows private policies and interfaces seamlessly with the current BGP infrastructure, requiring no changes to routers. We build a prototype to evaluate our proposed architecture using Hyperledger, we analyze its performance using a real-world BGP dataset. Our results show that our architecture scales linearly with relevant metrics. Additionally, we validate the architecture preventing an artificially introduced route leak in a realistic 10 AS topology.
A boardroom election is an election with a small number of voters carried out with public communications. We present BVOT, a self-tallying boardroom voting protocol with ballot secrecy, fairness (no tally information is available before the polls close), and dispute-freeness (voters can observe that all voters correctly followed the protocol). BVOT works by using a multiparty threshold homomorphic encryption system in which each candidate is associated with a masked unique prime. Each voter engages in an oblivious transfer with an untrusted distributor: the voter selects the index of a prime associated with a candidate and receives the selected prime in masked form. The voter then casts their vote by encrypting their masked prime and broadcasting it to everyone. The distributor does not learn the voter's choice, and no one learns the mapping between primes and candidates until the audit phase. By hiding the mapping between primes and candidates, BVOT provides voters with insufficient information to carry out effective cheating. The threshold feature prevents anyone from computing any partial tally---until everyone has voted. Multiplying all votes, their decryption shares, and the unmasking factor yields a product of the primes each raised to the number of votes received. In contrast to some existing boardroom voting protocols, BVOT does not rely on any zero-knowledge proof; instead, it uses oblivious transfer to assure ballot secrecy and correct vote casting. Also, BVOT can handle multiple candidates in one election. BVOT prevents cheating by hiding crucial information: an attempt to increase the tally of one candidate might increase the tally of another candidate. After all votes are cast, any party can tally the votes.
Since the initial launch of Bitcoin by Satoshi Nakamoto in 2009, decentralized digital currencies have long been of major interest in both the academia and the industry. Till today, there are more than 3000 different cryptocurrencies over the internet. Each one relies on mathematical soundness and cryptographic wit to provide unique properties in addition to securing basic correctness. A common misbelief for cryptocurrencies is that they provide complete anonymity by replacing people's real-life identity with a randomly generated wallet address in payments. However, this "pseudonymity" is easily breakable under the public ledger. Many attacks demonstrate ways to deanonymize people through observing the transaction patterns or network interactions. Thus, cryptocurrency fungibility has become a popular topic in the research community. This report reviews a partial list of existing schemes and describes an alternative implementation, Eth-Tumbler. Eth-Tumbler utilizes layered encryption and multiple signatures and thus efficiently hides a user under k-anonymity.
Open access
2 source records
cs.CR
Blockchain Technology Applications and Security
Advanced Steganography and Watermarking Techniques
We propose a secure and efficient implementation of fungible tokens on Bitcoin. Our technique is based on a small extension of the Bitcoin script language, which allows the spending conditions in a transaction to depend on the neighbour transactions. We show that our implementation is computationally sound: that is, adversaries can make tokens diverge from their ideal functionality only with negligible probability.
J Dharani, K Sundarakantham, Kunwar Singh, S. Mercy Shalinie
Blockchain technology has gained its attention from its application in bitcoin which circumvented the problem of double spending that existed in the prior digital currencies, through validation. Particularly permissioned blockchain framework became popular with organizations forming consortium that allowed only authorized entities to participate in the network. Hyperledger Fabric, a popular distributed ledger technology hosted by Linux Foundation has remarkable features because of the fact that it is open source. It stands out from other frameworks as it focuses on the privacy-preserving requirements of the enterprises. Apart from only allowing authenticated organizations to participate in the network it implements channels that allows a subset of organizations to communicate concealing the existence of such a channel to other members. Optionally fabric also provides anonymity and unlinkability of the participating clients through a cryptographic protocol suite called Idemix that operates based on zero-knowledge proofs. Fabric follows the execute-order-validate transaction flow as opposed to order-execute flow that had certain limitations in other platforms. For executing the transactions submitted by the clients, fabric has designated endorsing peers which holds the smart contract - programmable business logic. Endorsing peers or endorsers execute the transactions and attach their signatures to the results for validation purpose. But revealing the endorser identities may be a problem when there is conflict of interest among the enterprises. Hence to have an unbiased flow of work it is important to conceal the endorser identity. According to [1] anonymization of endorsing peers is still a open problem in fabric community. We propose a solution to this problem which uses linkable threshold ring signatures that conceals the identity of endorsers. Ring signatures are known for preserving the privacy of the signer in a group. Threshold ring signature allows t-out-of-n signers to collaborate on the signing procedure. Employing threshold ring signature implicitly addresses one more problem stated in [10] where the verifiers need to manually count the valid ring signature that increases the verification time. This process of separately verifying each of the signatures and checking if the number of signatures is more than the threshold value is replaced by having just one threshold signature collaboratively signed by the required endorsers.
Michael Rodler, Wenting Li, Ghassan Karame, Lucas Davi
Recent attacks exploiting errors in smart contract code had devastating consequences thereby questioning the benefits of this technology. It is currently highly challenging to fix errors and deploy a patched contract in time. Instant patching is especially important since smart contracts are always online due to the distributed nature of blockchain systems. They also manage considerable amounts of assets, which are at risk and often beyond recovery after an attack. Existing solutions to upgrade smart contracts depend on manual and error-prone processes. This paper presents a framework, called EVMPatch, to instantly and automatically patch faulty smart contracts. EVMPatch features a bytecode rewriting engine for the popular Ethereum blockchain, and transparently/automatically rewrites common off-the-shelf contracts to upgradable contracts. The proof-of-concept implementation of EVMPatch automatically hardens smart contracts that are vulnerable to integer over/underflows and access control errors, but can be easily extended to cover more bug classes. Our extensive evaluation on 14,000 real-world (vulnerable) contracts demonstrate that our approach successfully blocks attack transactions launched on these contracts, while keeping the intended functionality of the contract intact. We perform a study with experienced software developers, showing that EVMPatch is practical, and reduces the time for converting a given Solidity smart contract to an upgradable contract by 97.6 %, while ensuring functional equivalence to the original contract.
Elections are the foundations of democracy. To uphold democratic principles, researchers have proposed systems that ensure the integrity of elections. It is a highly interdisciplinary field, as it can be studied from a technical, legal or societal points of view. While lawyers give a legal framework to the voting procedures, security researchers translate these rules into technical properties that operational voting systems must satisfy, notably privacy and verifiability. If Privacy aims to protect vote-secrecy and provide coercion-resistance to the protocol, Verifiability allows voters to check that their vote has been taken into account in the general outcome, contributing to the assurance of the integrity of the elections. To satisfy both properties in a voting system, we rely on cryptographic primitives such as encryption, signatures, commitments schemes, or zero-knowledge proofs, etc. Many protocols, paper-based or electronic-based, have been designed to satisfy these properties. Although the security of some protocols, and their limits, have been analysed from a technical perspective, the usability has often been shown to have very low rates of effectiveness. The necessary cryptographic interactions have already shown to be one contributor to this problem, but the design of the interface could also contribute by misleading voters. As elections typically rarely happen, voters must be able to understand the system they use quickly and mostly without training, which brings the user experience at the forefront of the designed protocols. In this thesis, the first contribution is to redefine privacy and verifiability in the context of tracker-based verifiable schemes. These schemes, using a so-called tracking number for individual verification, need additional user steps that must be considered in the security evaluation. These security definitions are applied to the boardroom voting protocol F2FV used by the CNRS, and the e-voting protocol Selene, both use a tracker-based procedure for individual verifiability. We provide proofs of security in the symbolic model using the Tamarin prover. The second contribution is an implementation of the Selene protocol as a mobile and a web application, tested in several user studies. The goal is to evaluate the usability and the overall user experience of the verifiability features, as well as their understanding of the system through the evaluation of mental models. The third contribution concerns the evaluation of the voters' understanding of the coercion mitigation mechanism provided by Selene, through a unique study design using game theory for the evaluation of voters. Finally, the fourth contribution is about the design of a new voting scheme, Electryo, that is based on the Selene verification mechanisms but provides a user experience close to the standard paper-based voting protocols.
Iñigo Querejeta-Azurmendi, David Arroyo, Jorge López Hernández-Ardieta, Luis Hernández Encinas
This paper proposes NetVote, an internet voting protocol where usability and ease in deployment are a priority. We introduce the notion of strict coercion resistance, to distinguish between vote-buying and coercion resistance. We propose a protocol with ballot secrecy, practical everlasting privacy, verifiability and strict coercion resistance in the re-voting setting. Coercion is mitigated via a random dummy vote padding strategy to hide voting patterns and make re-voting deniable. This allows us to build a filtering phase with linear complexity, based on zero knowledge proofs to ensure correctness while maintaining privacy of the process. Voting tokens are formed by anonymous credentials and pseudorandom identifiers, achieving practical everlasting privacy, where even if dealing with a future computationally unbounded adversary, vote intention is still hidden. It is not assumed for voters to own cryptographic keys prior to the election, nor store cryptographic material during the election. This property allows voters not only to vote multiple times, but also from different devices each time, granting the voter a vote-from-anywhere experience. This paper builds on top of the paper published in CISIS’19. In this version, we modify the filtering. Moreover, we formally define the padding technique, which allows us to perform the linear filtering scheme. Similarly we provide more details on the protocol itself and include a section of the security analysis, where we include the formal definitions of strict coercion resistance and a game based definition of practical everlasting privacy. Finally, we prove that NetVote satisfies them all.
Marta Poblet, Darcy W E Allen, Oleksii Konashevych, Aaron M. Lane · 5 authors
Oracles were trusted sources of knowledge for public deliberation in classical Athens. Very much like expert and technical knowledge, divine advice was embedded in the deliberation and decision-making process of the democratic Assembly. While the idea of religious divination is completely out of place in our contemporary democracies, oracles made a technological comeback with modern computer science and cryptography and, more recently, the emergence of the blockchain as a “trust machine”. This paper reviews the role of oracles in Athenian democracy and, stemming from the renewed use of the term in computer sciences and cryptography, analyses the case of oracles in the nascent blockchain ecosystem. The paper also proposes a sociotechnical approach to the use of distributed oracles as informational devices to assist deliberative processes in digital democracy settings, and considers the limits that such an approach may face.
Efficient and reliable access control in smart cities is critical for the protection of various resources for decision making and task execution. Existing centralized access control schemes suffer from the limitations of single point of failure, low reliability, and poor scalability. This article, therefore, proposes a distributed and reliable access control framework for smart cities by combining the blockchain smart contract technology and the attribute-based access control (ABAC) model. The framework consists of one policy management contract (PMC) for managing the ABAC policies, one subject attribute management contract (SAMC) for managing the attributes of subjects (i.e., entities accessing resources), one object attribute management contract (OAMC) for managing the attributes of objects (i.e., resources being accessed), and one access control contract (ACC) for performing the access control. To show the feasibility of the proposed framework, we construct a local private Ethereum blockchain system to implement the four smart contracts and also conduct experiments to evaluate the monetary cost as well as to compare the proposed framework with an existing access control list (ACL)-based scheme. The experimental results show that although the proposed scheme consumes more money than the ACL-based scheme at the deployment stage, it introduces less monetary cost during the system running especially for large-scale smart cities.
Amrita Dhillon, Grammateia Kotsialou, Peter McBurney, Luke Riley
This work discusses the potential of a blockchain based infrastructure for a decentralised online voting platform. When compared to paper based voting, online voting can vastly increase the speed that votes can be counted, expand the overall accessibility of the election system and decrease the cost of turnout. Yet despite these advantages, online voting for political office is subject to fraud at various levels due to its centralised nature. In this paper, we describe a general architecture of a centralised online voting system and detail which areas of such a system are vulnerable to electoral fraud. We then proceed to introduce the key ideas underlying blockchain technology as a decentralised mechanism that can address these problems. We discuss the advantages and weaknesses of the blockchain technology, the protocols the technology uses and what criteria a good blockchain protocol should satisfy (depending on the voting application). We argue that the decentralisation inherent in the blockchain technology could increase the public's trust in national elections, as well as eliminate voter impersonation and double voting. We conclude with a discussion regarding how economists and social scientists can collaborate with the blockchain community in a research agenda on the design of efficient blockchain protocols and new voting systems such as liquid democracy.
Christian Killer, Lucas Thorbecke, Bruno Rodrigues, Eder J. Scheid · 6 authors
Trust in electoral processes is fundamental for democracies. Further, the identity management of citizen data is crucial, because final tallies cannot be guaranteed without the assurance that every final vote was cast by an eligible voter. In order to establish a basis for a hybrid public verifiability of voting, this work (1) introduces Proverum, an approach combining a private environment based on private permissioned Distributed Ledgers with a public environment based on public Blockchains, (2) describes the application of the Proverum architecture to the Swiss Remote Postal Voting system, mitigating threats present in the current system, and (3) addresses successfully the decentralized identity management in a federalistic state.
Juan Velandia Botello, Andrés Pardo Mesa, Fabián Ardila Rodríguez, Daniel Díaz López · 6 authors
The Internet of Things (IoT) paradigm has revolutionized several industries (e.g., manufacturing, health, transport, education, among others) by allowing objects to connect to the Internet and, thus, enabling a variety of novel applications. In this sense, IoT devices have become an essential component of smart cities, allowing many novel and useful services, but, at the same time, bringing numerous cybersecurity threats. The paper at hand proposes BlockSIEM, a blockchain-based and distributed Security Information and Event Management (SIEM) solution framework for the protection of the aforementioned smart city services. The proposed SIEM relies on blockchain technology to securely store and access security events. Such security events are generated by IoT sentinels that are in charge of shielding groups of IoT devices. The IoT sentinels may be deployed in smart city scenarios, such as smart hospitals, smart transport systems, smart airports, among others, ensuring a satisfactory level of protection. The blockchain guarantees the non-repudiation and traceability of the registry of security events due to its features. To demonstrate the feasibility of the proposed approach, our proposal is implemented using Ethereum and validated through different use cases and experiments.
This work analyses blockchain-mediated decentralization based on a systematic review of the scholarly understanding of the term ‘decentralization’ across multiple disciplines from computer to political sciences, examining how its various meanings are reflected in popular discourse on blockchains and distributed ledgers. The paper aims to capture the rigorous cross-domain understanding of decentralization and its most important features, and to map the commonalities and differences between it and some closely related concepts such as distribution, disintermediation and peer-to-peer (P2P). Across all domains, decentralization appears to be used as a solution to problems requiring non-trivial coordination across heterogeneous stakeholders. Blockchain-mediated decentralization appears to have unique characteristics reflecting an idiosyncratic set of authority-related values prevalent in so-called ‘crypto’ online communities. Within blockchain space, the article argues against the binary positioning of ‘decentralization’ and ‘centralization’, proposing a dialectical approach and arguing that a system’s authority allocation is a quality positioned on a spectrum between purely decentralized and completely centralized, noting how a blockchain set-up could simultaneously both have facets that are significantly centralized and others that are not. The authors document their systematic review findings and propose a framework for understanding blockchain-mediated decentralization, suggesting a definition, and outlining new directions for further human-centric research into distributed ledger technologies and for designing decentralized ecosystems.
Lukas Mastilak, Marek Galinski, Pavol Helebrandt, Ivan Kotuliak · 5 authors
Communication on the Internet consisting of a massive number of Autonomous Systems (AS) depends on routing based on Border Gateway Protocol (BGP). Routers generally trust the veracity of information in BGP updates from their neighbors, as with many other routing protocols. However, this trust leaves the whole system vulnerable to multiple attacks, such as BGP hijacking. Several solutions have been proposed to increase the security of BGP routing protocol, most based on centralized Public Key Infrastructure, but their adoption has been relatively slow. Additionally, these solutions are open to attack on this centralized system. Decentralized alternatives utilizing blockchain to validate BGP updates have recently been proposed. The distributed nature of blockchain and its trustless environment increase the overall system security and conform to the distributed character of the BGP. All of the techniques based on blockchain concentrate on inspecting incoming BGP updates only. In this paper, we improve on these by modifying an existing architecture for the management of network devices. The original architecture adopted a private blockchain implementation of HyperLedger. On the other hand, we use the public blockchain Ethereum, more specifically the Ropsten testing environment. Our solution provides a module design for the management of AS border routers. It enables verification of the prefixes even before any router sends BGP updates announcing them. Thus, we eliminate fraudulent BGP origin announcements from the AS deploying our solution. Furthermore, blockchain provides storage options for configurations of edge routers and keeps the irrefutable history of all changes. We can analyze router settings history to detect whether the router advertised incorrect information, when and for how long.
A blockchain is a distributed, digitized and consensus-based secure information storage mechanism. The present article provides an overview of blockchain based e-voting systems. The primary purpose of this review is to study the up-to-date state of blockchain-based voting research along with associated possible challenges while aiming to forecast future directions. The methodology applied in the review is a systematic review approach. Following an introduction to the basic structure and features of the blockchain in relation to e-voting, we provide a conceptual description of the desired blockchain-based e-voting application. Symmetrical and asymmetrical cryptography improvements play a key role in developing blockchain systems. We have extracted and reviewed 63 research papers from scientific databases that have advised the adoption of the blockchain framework to voting systems. These articles indicate that blockchain-supported voting systems may provide different solutions than traditional e-voting. We classified the main prevailing issues into the five following categories: general, integrity, coin-based, privacy and consensus. As a result of this research, it was determined that blockchain systems can provide solutions to certain problems that prevail in current election systems. On the other hand, privacy protection and transaction speed are most frequently emphasized problems in blockchain applications. Security of remote participation and scalability should be improved for sustainable blockchain based e-voting. It was concluded that frameworks needed enhancements in order to be used in voting systems due to these reservations.
Open access
Internet Traffic Analysis and Secure E-voting
Blockchain Technology Applications and Security
Advanced Steganography and Watermarking Techniques
Abstract Currently, attribute-based authentication provides a feasible solution for fine-grained access control in cloud environment. However, the existing schemes can not solve the following problems at the same time, that is, how to ensure that the computation cost of the client does not depend on the size of underlying access structure, and how to introduce distributed authorities to manage and maintain the attribute universe. To solve the above problems, an efficient multi-authority attribute-based authentication scheme is proposed. The new scheme uses the technique of distributed attribute-based encryption to realize the access control of anonymous users, and reduces users’ computation burden by optimizing the standard implementation zero-knowledge proof and outsourcing users’ computing tasks in the authentication stage. Under the new definition of security, it can be proved that the new scheme is secure and satisfies many attractive properties, such as introducing distributed authorities, supporting outsourcing computation, satisfying attribute anonymity.
The increasing of digital technology today has helped many people to fulfill their needs. But the election system, still conventionally using paper in its implementation. Elections in general still use a centralized system, where there is an organization that manages it. Some of the problems that may occur in traditional electoral systems are that there are organizations that have full control over the database and system, so the possibility of hacking the database is quite a big opportunity.Blockchain innovation is one arrangement that can be utilized in light of the fact that it has a decentralized framework and the whole database is duplicated by all clients. Blockchain itself has been used by Bitcoin and Ethereum cryptocurrency which is known as a decentralized system. By using the blockchain in database recording on an e-voting system can reduce one source of fraud that is database manipulation. This study discusses the recording of voting data using blockchain technology. The implementation of Smart Contracts contained in the Ethereum Blockchain will be implemented to create this voting system
Artificial intelligence (AI) has demonstrated huge potential in a variety of real-world applications. However, some significant considerations like fairness, transparency and trustworthiness are still challenging when applying AI to trust-oriented applications such as E-voting. E-voting plays a significant role in democratic societies, which requires voters and initiators have strong mutual trust. In this paper, we aim to facilitate the consolidation of AI ecosystems by developing a blockchain-based traceable self-tallying e-voting system. We take advantage of an event-oriented linkable group signature and a homomorphic time-lock puzzle to balance the anonymity and accountability, and the voting scale and efficiency of an e-voting system. The proposed e-voting protocol supports additional functions like multi-choice and self-tallying. We prove that the proposed protocol satisfies anonymity, time-bounded privacy, linkability and full-traceability. We also evaluate the time cost of off-chain operations and the gas cost of on-chain operations, which show the proposed e-voting protocol is practical and can be adopted in real-world applications.
Alberto García-Martínez, Stefano Angieri, Bingyang Liu, Fei Yang · 5 authors
The current mechanism to secure Border Gateway Protocol relies on the resource public key infrastructure (RPKI) for route origin authorization. The RPKI implements a hierarchical model that intrinsically makes lower layers in the hierarchy susceptible to errors and abuses from entities placed in higher layers. In this article, we present InBlock, a distributed autonomous organization that provides decentralized management of IP addresses based on blockchain, embedding an alternative trust model to the hierarchical one currently implemented by the RPKI. By leveraging on blockchain technology, InBlock requires consensus among the involved parties to change existent prefix allocation information. InBlock also fulfills the same objectives as the current IP address allocation system, i.e., uniqueness, fairness, conservation, aggregation, registration, and minimized overhead. InBlock is implemented as a set of blockchain smart contracts in Ethereum, performing all the functions needed for the management of a global pool of addresses without human intervention. Any entity may request an allocation of addresses to the InBlock registry by solely performing a (crypto) currency transfer to the InBlock. We describe our InBlock implementation and we perform several experiments to show that it enables fast address registering and incurs in very low management costs.
Ben Weintraub, Cristina Nita-Rotaru, Stefanie Roos
Payment channel networks (PCN) enable scalable blockchain transactions without fundamentally changing the underlying distributed ledger algorithm. However, routing a payment via multiple channels in a PCN requires locking collateral for potentially long periods of time. Adversaries can abuse this mechanism to conduct denial-of-service attacks. Previous work on denial-of-service attacks focused on source routing, which is unlikely to remain a viable routing approach as these networks grow.
In this work we examine the effectiveness of attacks in PCNs that use routing algorithms based on local knowledge, where compromised intermediate nodes delay or drop transactions to create denial-of-service. We focus on SpeedyMurmurs as a representative of such protocols. Our attack simulations show that SpeedyMurmurs is resilient to attacks by randomly selected intermediate nodes because it dynamically adjusts using local knowledge. We further consider attackers that control a significant fractions of paths and we show that this ability to route around problematic regions becomes insufficient for such attackers. We propose methods to incentivize payment channel networks with less central nodes and more diverse paths and show through simulation that these methods effectively mitigate the identified denial-of-service attacks.
Cherukupalli Veda Vyasa Aditya, Rajesh Kannan Megalingam
Zero knowledge proof is a powerful cryptographic protocol that is utilized to establish data security whilst ensuring and maintaining user anonymity. ZKP has relatively less complex computational requirements as compared to the other protocols for authentication. Conventional authentication schemes are susceptible to attacks such as MiTM, IP spoofing, DoS, replay and other eavesdropping based attacks, when the data is shared across an untrusted network. This paper shows an approach to ensure authentication of a device over an untrusted network whilst maintaining and safeguarding user credentials, by using the concepts of ZKP protocol.