Vincent Messié, Gaël Fromentoux, Xavier Marjou, Nathalie Labidurie Omnes
In this article, we highlight a novel solution for densifying 5G access networks. Taking benefits from local actors and prosumers, our proposal allows offering a better connectivity to end-users in a model involving network operators and a crowd of local actors. We show that building a multi-actors and densified access network infrastructure has become possible in a distributed way. Incumbent actors with a large footprint act as trusted partners securing the infrastructure and providing guarantees, while the crowd of local actors deploys multiple access points and are rewarded for their contribution. Rewarding is possible thanks to a distributed Bandwidth & Identity ledger along with a Proof of Bandwidth (PoB) mechanism. This article presents the main principles of this new connectivity platform, BALAdIN (Bandwidth Ledger AccountIng Networks), which relies on a consortium blockchain with access control mechanisms removing communitarian Wifi and ad hoc networks drawbacks. Indeed, combining distributed ledgers and edge networks allows local actors to cooperate with trusted parties, which leverages the full potential of multi-actors access networks.
Kazi Md. Rokibul Alam, Shinsuke Tamura, Sazia Rahman, Yasuhiko Morimoto
This paper improves the performance of the revised-simplified verifiable re-encryption mixnet (R-SVRM) based e-voting scheme by introducing confirmation numbers (CNs) that are used in the CN based e-voting scheme. Although CN based and R-SVRM based schemes had made e-voting schemes more practical by excluding zero knowledge proof (ZKP) that requires large volume of computations, still they are not efficient enough. Namely, the CN based scheme adopts RSA encryption functions that are not probabilistic or commutative, therefore to satisfy essential requirements of elections, extra random factors are necessary for individual votes, election authorities must sign on votes and they must keep encryption keys as their secrets. On the other hand, although the R-SVRM based scheme uses ElGamal encryption functions that are probabilistic and commutative, vote forms in it is complicated, i.e., vote forms consist of at least 3 items and they include information about candidates as exponents. The improved scheme simplifies vote forms by exploiting CNs, and extensively reduces the number of operations required for individual votes. Also, the scheme successfully satisfies all essential requirements of e-voting systems, i.e., it is endowed with features about privacy, robustness, accuracy, incoercibility and fairness as CN based and R-SVRM based schemes are.
Internet Traffic Analysis and Secure E-voting
Cryptography and Data Security
Advanced Steganography and Watermarking Techniques
The concept of virtual currencies is an emerging, and perhaps unexpected development in the modern financial world. Bitcoin can be regarded as the first successful virtual currency, followed by many other implementations. Analogous to paper currencies, it is apparent that privacy and anonymity are two pivotal considerations that affect the adoption of virtual currencies by users. However, many studies have identified several problems associated with the privacy and anonymity of Bitcoin. Consequently, a large number of attempts have been made to address these issues, yet it has been proven that many such solutions do not provide an acceptable level of anonymity. This survey presents an account of the level of anonymity achieved through those and attempts to provide a comparative evaluation across different constructions.
E-government provides access to services anytime anywhere. There are many e-Government frameworks already exist to integrate e-government services, but efficient full interoperability still a challenge. Interoperability per se can be modeled via four maturity stages, in which the interoperability zone is the holy grail of full interoperability to be reached ultimately with strategy alignment. As e-government services shift in the same way as e-commerce with value chain, this implicitly implies the possibility of benefiting from blockchain with e-government. Blockchain is a nascent promising architecture, whose transactions are permanent, verifiable, and recorded in a distributed ledger. This research article suggests applying blockchain in achieving e- government interoperability. Forms are juxtaposed on the outer borders of the system. These forms adopt those used by UK government, because they are standard as well as they are available for Python developers. Once a form has been completed, PySOA calls the requested service, before storing the data in Ontology Blockchain. After the service is performed, the policies are analyzed in batch processing using quantgov. A report is submitted to the central government periodically. Ontology Blockchain has a dual effect. On the one hand, it works as a secure data storage. On the other hand, it cooperates with PySOA in supporting both technology and semantic interoperability . The most important feature of the proposed method is the presence of (Government Interoperability Zone Alignment; GIZA), which acts as a backbone that coherently connects the internal subcomponents. This linkage is possible, because each form has an title, that corresponds to the appropriate service name. Each service in turn has a counterpart in the wallets stored in Ontology blockchain. To measure interoperability empirically, there is a need for metrics. This study adopts and quantizes a standard interoperability matrix along three dimensions of interoperability of Conceptual (Syntax& Semantics), Organizational (Responsibilities& Organization per se), and Technology (Platform& Communication). While concerns are : data, business, service, and process. Any deviation from the standard could contributes to the interoperability score (counting mismatches) or interoperability grade (counting absolute differences). An estimation is performed, for 1000 total random cases. It is estimated that the probability of getting a conceptual/technical interoperability score as large as the standard strategy score is (713 /1000 = 0.713 (2 in 3). It is estimated too that the probability of getting a organizational interoperability score as large as the standard strategy score is (712 /1000 = 0.712 (2 in 3). Then, Markov model is proposed to provide an accurate representation of the evolution of the strategies over time.
Peter B. Rønne, Arash Atashpendar, Kristian Gjøsteen, Peter Y. A. Ryan
We present an approach for performing the tallying work in the coercion-resistant JCJ voting protocol, introduced by Juels, Catalano, and Jakobsson, in linear time using fully homomorphic encryption (FHE). The suggested enhancement also paves the path towards making JCJ quantum-resistant, while leaving the underlying structure of JCJ intact. The exhaustive, comparison-based approach of JCJ using plaintext equivalence tests leads to a quadratic blow-up in the number of votes, which makes the tallying process rather impractical in realistic settings with a large number of voters. We show how the removal of invalid votes can be done in linear time via a solution based on recent advances in various FHE primitives such as hashing, zero-knowledge proofs of correct decryption, verifiable shuffles and threshold FHE. We conclude by touching upon some of the advantages and challenges of such an approach, followed by a discussion of further security and post-quantum considerations.
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.
Elie Kfoury, Jose Gomez, Jorge Crichigno, Elias Bou‐Harb · 5 authors
Network Address Translation (NAT) is a method that enables devices with private IP addresses to connect to the Internet by sharing a public IP address. Traversing the NAT device remains a challenge for a wide range of applications such as Voice over IP (VoIP) and Internet of Things (IoT). The Port Control Protocol (PCP) is a relatively new protocol standardized by the Internet Engineering Task Force (IETF) to solve the NAT traversal issues. It allows a NATed device to request and manage a mapping between its private IP address and transport-layer port to a public IP address and port. As PCP requires an application-dependent method for distributing the mappings to remote hosts, several attacks can target the distributing server and render the communication channel vulnerable. In this paper, we propose and implement a decentralized Blockchain-based approach for distributing PCP-mappings, enabling secure end-to-end (e2e) direct communications without any trusted third party server. NATed devices register their PCP mappings and public keys into the Blockchain, and other peers can then learn about these mappings to establish end-to-end secure direct communications. The implementation verifies that the system is feasible in terms of transactions fees, can simplify and secure end-to-end direct communications, and can interwork with conventional security methods.
Permissionless Blockchains sind dezentrale Systeme, die Konsens erzielen. Das prominenteste Beispiel einer Permissionless Blockchain ist das elektronische Zahlungssystem Bitcoin, welches Konsens über die von Teilnehmern des Systems erzeugten Finanztransaktionen erzielt. Während verteilter Konsens seit Jahrzehnten Gegenstand zahlreicher Forschungsarbeiten ist, ist Bitcoin das erste bekannte System, welches Konsens im sog. permissionless-Modell erzielt, d.h. ohne die vorausgehende Feststellung der Identitäten der Teilnehmer des Systems. Die Teilnehmer von Permissionless Blockchains kommunizieren über ein unstrukturiertes Peer-to-Peer (P2P) Netzwerk miteinander. Da das Verfahren zur Konsensbildung von Permissionless Blockchains auf Daten basiert, die über dieses P2P-Netzwerk übertragen werden, können Sicherheitslücken in der Netzwerkschicht auch die Konsensbildung und damit die angestrebte Funktion des Systems beeinflussen. Während unstrukturierte P2P-Netzwerke in der Vergangenheit umfassend analysiert wurden, führt ihr Einsatz in Permissionless Blockchains zu Sicherheitsanforderungen und Angreifermodellen, die bisher noch nicht berücksichtigt wurden. Obwohl einzelne Angriffe auf die Netzwerkschicht von Permissionless Blockchains analysiert wurden, ist unklar, welche Sicherheitseigenschaften die Netzwerkschicht von Permissionless Blockchains haben sollte. Diese Unklarheit motiviert die erste in dieser Dissertation behandelte Forschungsfrage: Wie können Anforderungen und Zielkonflikte, die in den Mechanismen der Netzwerkschicht von Permissionless Blockchains vorhanden sind, untersucht werden? In dieser Dissertation wird eine Systematisierung von Angriffen auf die Netzwerkschicht von Bitcoin vorgestellt, in der Angriffe hinsichtlich der angegriffenen Mechanismen und der Auswirkungen der Angriffe auf höhere Schichten des Systems kategorisiert werden. Basierend auf der Systematisierung werden fünf Anforderungen für die Netzwerkschicht von Permissionless Blockchains abgeleitet: Leistung, niedrige Beteiligungskosten, Anonymität, Robustheit gegen Denial-of-Service Angriffe sowie Topologieverschleierung. Darüber hinaus werden der Entwurfsraum der Netzwerkschicht aufgezeigt und der Einfluss von Entwurfsentscheidungen auf die Erfüllung von Anforderungen qualitativ untersucht. Die durchgeführten Systematisierungen weisen auf inhärente Zielkonflikte sowie Forschungsmöglichkeiten hin und unterstützen die Entwicklung von Permissionless Blockchains. Weiterhin wird auf Grundlage von seit 2015 durchgeführten Messungen eine Charakterisierung des Bitcoin-P2P-Netzwerks präsentiert. Die Charakterisierung ermöglicht die Parametrisierung und Validierung von Simulationsmodellen und die Bewertung der Zuverlässigkeit von realen Experimenten. Darüber hinaus gewährt die Netzwerkcharakterisierung Einblicke in das Verhalten von Netzwerkknoten und deren Betreibern. Beispielsweise kann gezeigt werden, dass Sybil-Ereignisse in der Vergangenheit im Bitcoin-P2P-Netzwerk stattgefunden haben und dass die Leistung und die Anonymitätseigenschaften der Transaktions- und Blockausbreitung durch Implementierungs- und Protokolländerungen verbessert worden sind. Auf Grundlage dieser Charakterisierung werden zwei ereignisdiskrete Simulationsmodelle des Bitcoin-P2P-Netzwerks entworfen. Die Modelle werden durch einen Vergleich der simulierten Informationsausbreitungsverzögerung mit der beobachteten Informationsausbreitungsverzögerung im realen Netzwerk validiert. Da der Vergleich eine hohe Übereinstimmung zeigt, ermöglichen die vorgestellten Simulationsmodelle die Simulation des Bitcoin-Netzwerks mit einer Genauigkeit, die für die Analyse von Angriffen im Bitcoin-Netzwerk ausreicht. Die vorgestellten Simulationsmodelle sowie die durchgeführte Systematisierung von Angriffen verdeutlichen die Bedeutung der Kenntnis der Netzwerktopologie als Grundlage für Forschung und die Analyse von Deanonymisierungsangriffe. Daher adressiert die zweite Forschungsfrage dieser Dissertation Methoden der Topologieinferenz und der Deanonymisierung: Unter welchen Voraussetzungen und in welchem Maße sind netzwerkbasierte Topologieinferenz und Deanonymisierung in Bitcoin (un)möglich? Diese Frage wird durch Anwendung der vorgeschlagenen Methodenkombination aus Messungen, Simulationen und Experimenten beantwortet. In dieser Dissertation werden vier verschiedene Methoden zur Topologieinferenz vorgestellt und unter Verwendung von Experimenten und Simulationsstudien analysiert. Anhand von Experimenten wird gezeigt, dass ein Angreifer, der in der Lage ist, Verbindungen zu allen Knoten des Netzwerks zu etablieren, die direkten Nachbarn eines Netzwerkknotens mit hoher Sensitivität (recall) und Genauigkeit (precision) (87% recall, 71% precision) durch die Veröffentlichung von widersprüchlichen Transaktionen im Netzwerk herausfinden kann. Unter der Annahme eines passiven Angreifers, der in der Lage ist, sich mit allen erreichbaren Netzwerkknoten zu verbinden, war 2016 ein Rückschluss auf die Nachbarn eines Netzwerkknotens mit einer Sensitivität von 40% bei einer Genauigkeit von 40% durch Beobachtung von mindestens acht Transaktionen, die von diesem Netzwerkknoten stammen, möglich. Darüber hinaus ist es möglich, die Akkumulation mehrere Transaktionen zum Zwecke der Topologieinferenz zu geringen Kosten auszunutzen. Allerdings bleibt die erwartete Inferenzqualität aufgrund fehlender Validierungsmöglichkeiten unklar. Schließlich kann simulativ gezeigt werden, dass der Peer-Discovery-Mechanismus eines P2P-Netzwerks bei bestimmte Parametrisierungen Topologinferenz ermöglichen kann. Abschließend wird die Möglichkeit einer netzwerkbasierten Deanonymisierung bewertet, indem analysiert wird, ob eine Korrelation zwischen der IP-Adresse des Netzwerkknotens, der eine Transaktion veröffentlicht, und dem mutmaßlichen Ersteller der Transaktion besteht. Der zugrundeliegende Datensatz basiert auf den durchgeführten Messungen und besteht aus fast 10 Millionen Transaktionen mit zugehörigen IP-Adressen. Es wird gezeigt, dass Transaktionen von 5% bis 8.3% der Benutzer auffallend häufig von einzelnen Netzwerkknoten veröffentlicht wurden, was diese Benutzer dem Risiko netzwerkbasierter Deanonymisierungsangriffe aussetzt.
As the Internet has developed, media distribution services have spread. However, these distribution services have many problems. The blockchain technology can solve these problems. In this paper, this blockchain is defined as media blockchain and is classified into two categories. One is content security that means securing content using blockchain. The other is content right information that means tracing and managing right information using blockchain. We introduce and analyze the media blockchain.
Advanced Steganography and Watermarking Techniques
Carlos Eduardo Tofanim, Gabriel Moralo da Costa, Jean Paul Pezzutti, Matheus Casarin Giaculi
This study investigates the feasibility of applying blockchain technology to enhance the security and transparency of electronic voting systems. The research analyzes potential vulnerabilities and trust challenges associated with traditional electronic voting infrastructure and explores how distributed ledger technologies can be used to improve vote integrity and auditability. A prototype voting system was developed to simulate an online voting environment using blockchain as the underlying data storage mechanism. The system was implemented as a web application using ASP.NET MVC and C# within the .NET Framework environment, with blockchain functionality integrated through an open-source implementation adapted for the study. The prototype demonstrates how votes can be recorded as blockchain transactions, ensuring immutability and distributed verification of voting data. The architecture also includes a web-based user interface for vote selection and confirmation, as well as backend blockchain validation mechanisms responsible for maintaining the integrity of the distributed ledger. The study evaluates the technical feasibility of integrating blockchain with electronic voting processes and discusses potential advantages such as improved transparency, tamper resistance, and decentralized validation of election results. Although the study focuses primarily on the technical feasibility and proof-of-concept implementation, the findings suggest that blockchain-based voting systems could represent a promising approach for improving trust and security in digital electoral systems. Future research directions include scalability analysis, infrastructure requirements for nationwide implementation, and mechanisms for secure voter verification.