Ethereum is one of the largest blockchain platforms currently that has become a digital business environment for users. This platform is designed to allow decentralized transactions between anonymous users. Thus, the development of methods to identify user behavior profiles, keeping their identities anonymous, has the potential to leverage business on this platform. In this work, we investigate the use of machine learning to classify a user profile as professional or common based on the attributes of their transactions. This classification is challenging due to the small fraction of publicly labeled users in Ethereum and still the considerably smaller fraction of professional users. To conduct this investigation, we train models considering carefully balanced sets of transactions with labeled users. Our results show high performance models for the classification of profiles, achieving a performance greater than 90% for accuracy, precision, and other related measures. In addition, we have identified the most relevant features in transactions for this classification.
Vikram Kanth, Chad Bollmann, Murali Tummala, John McEachen
As digital trust has declined, services purporting to provide privacy and anonymity have become increasingly popular in today's online environment. While there are several examples of these types of applications, blockchain-based services like Bitcoin and Ethereum have emerged as a potential answer to some of these privacy concerns. Unfortunately, many of the same features that facilitate that privacy and anonymity can also be leveraged by nefarious actors to transmit and store information covertly. These features can also be used by government and military organizations for communications purposes. In this paper, we present a generic information hiding model incorporating anonymity that builds on existing classical steganographic models like the Prisoners' Problem. We then analyze our model with regards to blockchain protocols and present a novel blockchain-based address embedding scheme. Finally, we implement our scheme using the Ethereum platform.
Internet Traffic Analysis and Secure E-voting
Advanced Steganography and Watermarking Techniques
In cryptocurrencies, privacy of users is preserved using pseudonymity . However, it has been shown that pseudonymity does not result in anonymity if a user's transactions are linkable. This makes cryptocurrencies vulnerable to deanonymization attacks. The current solutions proposed in the literature suffer from at least one of the following issues: (1) requiring a trusted thirdâparty entity, (2) poor performance, and (3) incompatible with the standard structure of cryptocurrencies. In this article, we propose Unlinkable Coin (UCoin), a secure mixâbased approach to address these issues. In UCoin, the link between the input (payer) and output (payee) addresses in a transaction is broken. This is done by mixing the transactions of multiple users into a single aggregated transaction in which the output addresses have been secretly shuffled. In our protocol design, we first develop HDCânet, a secure shuffling protocol that enables a group of users to anonymously publish their data. Then, we deploy the proposed HDCânet protocol in the UCoin architecture (as a mixing unit) to generate the aggregate transactions. We show that UCoin (1) does not rely on a trusted thirdâparty, (2) can mix 50 transactions in 6.3 seconds that is 18% faster than the current solutions, and (3) is fully compatible with the architecture of cryptocurrencies.
Many countries have been using online voting systems instead of ballot papers. In such voting systems, voters can cast votes online using their cell phones, laptops, and other internet-connected devices. Online voting systems have centralized databases where a malicious attacker can hack, change or manipulate the database. Therefore, current online voting systems present a security concern for any government. Blockchain is a peer-to-peer technology in which data is stored in a tamper-proof ledger and maintained by participating peers. In this paper, we propose a secure online voting system using Ethereum Blockchain and Ethereum Smart Contracts. A voter can cast her vote securely after scanning her fingerprint and iris recognition. Our proposed methodology uses Paillier homomor-phic encryption and the private key shifting technique to ensure voter privacy and identity security.
Internet Traffic Analysis and Secure E-voting
Advanced Steganography and Watermarking Techniques
Mingyu Liang, Ioanna Karantaidou, Foteini Baldimtsi, Steven Gordon · 5 authors
Abstract We propose a new theoretical approach for building anonymous mixing mechanisms for cryptocurrencies. Rather than requiring a fully uniform permutation during mixing, we relax the requirement, insisting only that neighboring permutations are similarly likely. This is defined formally by borrowing from the definition of differential privacy. This relaxed privacy definition allows us to greatly reduce the amount of interaction and computation in the mixing protocol. Our construction achieves O ( n· polylog( n )) computation time for mixing n addresses, whereas all other mixing schemes require O ( n 2 ) total computation across all parties. Additionally, we support a smooth tolerance of fail-stop adversaries and do not require any trusted setup. We analyze the security of our generic protocol under the UC framework, and under a stand-alone, game-based definition. We finally describe an instantiation using ring signatures and confidential transactions.
Jochen SchĂ€fer, Christian MĂŒller, Frederik Armknecht
Abstract Bitcoin and similar cryptocurrencies are becoming increasingly popular as a payment method in both legitimate and illegitimate online markets. Such markets usually deploy a review system that allows users to rate their purchases and help others to determine reliable vendors. Consequently, vendors are interested into accumulating as many positive reviews (likes) as possible and to make these public. However, we present an attack that exploits these publicly available information to identify cryptocurrency addresses potentially belonging to vendors. In its basic variant, it focuses on vendors that reuse their addresses. We also show an extended variant that copes with the case that addresses are used only once. We demonstrate the applicability of the attack by modeling Bitcoin transactions based on vendor reviews of two separate darknet markets and retrieve matching transactions from the blockchain. By doing so, we can identify Bitcoin addresses likely belonging to darknet market vendors.
Pedro Casas, Matteo Romiti, Peter Holzer, Sami Ben Mariem · 6 authors
Proposed in 2016 and launched in 2018, the Bitcoin (BTC) Lightning Network (LN) can scale-up the capacity of the BTC blockchain network to process a significantly higher amount of transactions, in a faster, cheaper, and more privacy preserving manner. The number of LN nodes has been significantly increasing since 2018, and today there are more than twelve thousand nodes actively participating of so-called LN payment channels. The upcoming Taproot upgrade to the Bitcoin protocol would further boost the development and adoption of the LN. Taproot is the most significant upgrade to the Bitcoin network since the block size increase of 2017, and it will make LN transactions cheaper, more flexible, and more private. We focus on the characterization of the LN network topology, using network active measurements. By crawling the underlying P2P network supporting the Bitcoin LN over a span of 10-months, we unveil the LN in terms of size and location of its nodes as well as connectivity protocols, comparing it to the P2P IP network supporting the BTC blockchain. Among our findings, we show that IP addresses exposed by LN nodes correspond mainly to customer networks, even if most BTC nodes are actually deployed at major cloud providers, and that LN nodes significantly rely on anonymized networks and protocols such as Onion, with more than 40% of LN nodes connect through Tor.
Ioan-Mihail Stan, Ilie-Constantin Barac, Daniel E. Rosner
The ability to vote in state elections represents a basic right and expressing the vote is a civic obligation. However, the pandemics of COVID-19 showed us how such a simple process for a citizen may generate indirect barriers in expressing the electoral options. The risks of getting in contact with the virus made the classical voting method infeasible in times of crisis. Thus, a new opportunity arises, anticipated since 2016 by the Eurobarometer - the need to provide methods to vote over the Internet. Currently, in the European Union, only Estonia can provide citizens with such services. To overcome the current situation, we propose an architecture of a highly scalable e-election system implemented over the blockchain technology. The aim is to provide a general viable solution and to reduce the time to market, as a quick response to the current situation. The latter aspect is ensured by the Hyperledger Fabric, a permissioned, highly customizable, and integration-focused blockchain implementation. The paper provides a qualitative solution evaluation covering essential security aspects (e.g., resilience to Sybil Attack) and performance measurements (block sizing, state database performance). The contrast established with other platforms, is the simple but tamper-proof architectural view, focused on isolation and distribution of functions.
Blockchain technology has become very trendy and penetrated different domains, mostly due to the popularity of cryptocurrencies. Blockchain technology offers decentralized nodes for e-voting and is used to create e-voting systems, mainly because of their end-to-end verification benefits. This technology is an excellent replacement for traditional e-voting solutions with distributed performance, reliability and security. The following article provides an overview of e-voting systems based on blockchain technology. The main purpose of this analysis was to examine the current state of blockchain-based voting systems, as well as any associated difficulties in predicting future events.
Internet Traffic Analysis and Secure E-voting
Blockchain Technology Applications and Security
Advanced Steganography and Watermarking Techniques
Kamran, Muhammad Hammad Nasir, Muhammad Imran, Joon-Sung Yang
The traditional voting system has many flaws such as election manipulation, security breaches, transparency and privacy issues. These issues occur as the votes can be changed by a central authority in favor of one party when they are being counted manually or there can be human error while counting votes. This system puts a lot of trust in the central authority. Also, there is an economical issue due to the cost of security, human and ballot resources. Many of these issues are solved using the E-Voting system which has been successful in countries like Estonia that have implemented this system of voting. There is still an issue of universal verifiability of votes even in the Estonian E-Voting system. This paper conducts a study of various e-voting systems. From among the various existing methods, an effective blockchain based solution to solve the existing issues of E-voting has been explained. The blockchain is a database, distributed among all users on the network which will help in the verification of all votes cast without the need to put complete trust on a third-party system.
Internet Traffic Analysis and Secure E-voting
Cryptography and Data Security
Advanced Steganography and Watermarking Techniques
Lin Jin, Shuai Hao, Yan Huang, Haining Wang · 5 authors
Domain Name System (DNS) is known to present privacy concerns. To this end, decentralized blockchains have been used to host DNS records, so that users can synchronize with the blockchain to maintain a local DNS database and resolve domain names locally. However, existing blockchain-based solutions either do not guarantee a domain name is controlled by its "true" owner; or have to resort to DNSSEC, a not yet widely adopted protocol, for verifying ownership. In this paper, we present DNSonChain, a new blockchain-based naming service compatible with DNS. It allows domain owners to claim their domain ownership on the blockchain where DNS records are hosted. The core function of DNSonChain is to validate the domain ownership in a decentralized manner. We propose a majority vote mechanism that randomly selects multiple participants (i.e., voters) in the system to vote for the authority of domain ownership. To provide resistance to attacks from fraudulent voters, DNSonChain requires two rounds of voting processes. Our security analysis shows that DNSonChain is robust against several types of security failures, able to recover from various attacks. We implemented a prototype of DNSonChain as an Ethereum decentralized application and evaluate it on an Ethereum Testnet.
With the proliferation of social networks, user data is increasingly vulnerable to unauthorized access, profiling, and data breaches. Cryptography has emerged as a critical defense mechanism to ensure data confidentiality, integrity, and user privacy. This paper explores the application of modern cryptographic techniquesâsuch as homomorphic encryption, zero-knowledge proofs, and attribute-based encryptionâto enhance privacy controls within social networking platforms. It further highlights the challenges of balancing usability with security and presents solutions for deploying cryptographic protocols in dynamic, large-scale environments like Facebook, Twitter, and LinkedIn. The paper concludes with future directions for integrating decentralized privacy models using blockchain-based cryptographic frameworks.
Abstract: A decentralised, Secure, Peer-to-Peer Multi-Voting System on Ethereum Blockchain is a distributed ledger technology (DLT) that permits virtual votes to be transacted in a peer-to-peer decentralized network. Those transactions are validated and registered through every node of the network, so creating a transparent and immutable series of registered events whose truthfulness is supplied through a consensus protocol. Smart contract automates the execution of agreement that runs routinely as soon as the conditions are satisfied. Smart contract would not need any third parties consequently prevents time loss. By Eliminating the requirement for third parties, consequently, allows numerous processes to be extra efficient and economical. The system is secure, reliable, and anonymous. Smart contract is enforced for the Ethereum network using the Ethereum wallets and also the Solidity language. Users are capable of submit their votes immediately from their Ethereum wallets, and those transaction requests is handled with the consensus of each single Ethereum node. This creates a transparent environment for evoting. A lot of concerning efficiency of the peer-to-peer decentralized electoral system on Ethereum network along with application and the outcomes of implementation are provided in this paper. Keywords: Blockchain, Distributed Ledger Technology (DLT), Consensus Protocol, Smart Contracts, Ethereum, Solidity
Blockchain and machine learning (ML) have emerged as two disruptive technologies that could transform various sectors. Blockchain is known as peer to peer decentralized, distributed ledger technology that enables to store and exchange anything of value, it is deterministic, permanent and immutable. On the other hand, ML is the ability of computers to learn without being programmed, and it is probabilistic. Hence, when blockchain and ML converge, they surely would benefit from each other. Blockchain can enhance security of ML platforms, and ML can provide automation and optimization to the blockchain solutions. In this work, we advocate the importance of enhancing blockchain with ML algorithms, as a proof of principle we address the issue of secure and intelligent e-voting.The use of blockchain technology has brought tremendous different application domains, e-voting is one of them. Most existing e-Voting systems require central authority during the process of authentication and verification of the voter. In this paper we propose a safe online voting approach based on blockchain and ML to provide a solution to this issue. We use blockchain to ensure integrity and transparency of the votes, and ML for automating the verification process of eligible voters based on AI-powered oracle platform for face authentication. The proposed solution offers automation, security, and mobility to the voting system.
Blockchain Technology Applications and Security
Internet Traffic Analysis and Secure E-voting
Advanced Steganography and Watermarking Techniques
The security of HTTPS fundamentally relies on SSL/TLS certificates issued by Certificate Authorities (CAs), which, however, are vulnerable to be compromised to issue unauthorized certificates (i.e., certificates issued without domainsâ permission). Current countermeasures such as Certificate Transparency (CT) can only detect unauthorized certificates rather than preventing them. In this article, we presentPistis, a framework for issuing authorized and trusted certificates with the distributed ledger and Trusted Execution Environment (TEE) technology. InPistis, TEE nodes validate whether the domain in a requested certificate passes the domain ownership validation (i.e., under corresponding applicantsâ control) and submit attested results to a smart contract in the distributed ledger. The smart contract issues a certificate to the applicant when an attested result shows a pass. Therefore,Pistiscan ensure its issued certificates are authorized due to the domain ownership validation mechanism in the TEE. Furthermore, as the issued certificates are stored in a Merkle Patricia Tree (MPT) inPistis, they are trusted and can be verified by a normal user easily. The security ofPistisis formally proved in the Universally Composable (UC) framework. Compared with state-of-the-art,Pistisavoids potential damages by preventing unauthorized certificates from issuing.
Recently, two attacks were presented against Proof-of-Stake (PoS) Ethereum: one where short-range reorganizations of the underlying consensus chain are used to increase individual validators' profits and delay consensus decisions, and one where adversarial network delay is leveraged to stall consensus decisions indefinitely. We provide refined variants of these attacks, considerably relaxing the requirements on adversarial stake and network timing, and thus rendering the attacks more severe. Combining techniques from both refined attacks, we obtain a third attack which allows an adversary with vanishingly small fraction of stake and no control over network message propagation (assuming instead probabilistic message propagation) to cause even long-range consensus chain reorganizations. Honest-but-rational or ideologically motivated validators could use this attack to increase their profits or stall the protocol, threatening incentive alignment and security of PoS Ethereum. The attack can also lead to destabilization of consensus from congestion in vote processing.
Patrick McCorry, Maryam Mehrnezhad, Ehsan Toreini, Siamak F. Shahandashti · 5 authors
This article discusses secure methods to conduct e-voting over a blockchain in three different settings: decentralized voting, centralized remote voting, and centralized polling station voting. These settings cover almost all voting scenarios that occur in practice. A proof-of-concept implementation for decentralized voting over Ethereumâs blockchain is presented. This work demonstrates the suitable use of a blockchain not just as a public bulletin board but, more importantly, as a trustworthy computing platform that enforces the correct execution of the voting protocol in a publicly verifiable manner. We also discuss scaling up a blockchain-based voting application for national elections. We show that for national-scale elections the major verifiability problems can be addressed without having to depend on any blockchain. However, a blockchain remains a viable option to realize a public bulletin board, which has the advantage of being a âpreventiveâ measure to stop retrospective changes on previously published records as opposed to a âdetectiveâ measure like the use of mirror websites. CCS Concepts: âą Security and privacy ;
The blockchain provides a reliable and scalable method for enabling source-tracing functionality in large-scale Internet of Things (IoT) systems. Traditional blockchain-based source tracing applications are generally based on the hypothesis that the raw data collected by each IoT node are credible and consistent, which however may not always be the truth. As no mechanism ensures the reliability of the original data collected from the IoT devices, these data may be accidently screwed up or maliciously tampered with before they are uploaded on-chain. To address this issue, we propose the Multi-dimensional Certificates of Origin (MCO) method to filter out the potentially incredible data-till all the data uploaded to the chain are credible. To achieve this, we devise the Multi-dimensional Information Cross-Verification (MICV) and Multi-source Data Matching Calculation (MDMC) methods. MICV verifies whether a to-be-uploaded datum is consistent or credible, and MDMC determines which data should be discarded and which data should be kept to retain the most likely credible/untampered ones in the circumstance when data inconsistency appears. Large-scale experiments show that our scheme ensures on the credibility of data and off the chain with an affordable overhead.
Blockchain technology is in demand due to its key properties, such as immutability, transparency, distributed storage, and non-centric controls. The election is the primary process for forming a government at local, state, or federal levels in any democratic country. A fair election increases peopleâs faith in their government. An electronic voting system is a safer solution during this pandemic for the democratic voting system. However, the electronic voting system has a number of potential issues, including security and privacy breaches, the fear of cyber-attacks, the hijacking of the session, and identity theft. Using Blockchain, we can overcome many security and privacy issues as Blockchain uses a cryptographic hash and digital signatures for sending and verifying transactions in the peer-to-peer Blockchain network. Identity management is a critical issue in the election system as many fake voters are available and in the traditional election system, many fake votes are counted. We proposed a system that generates the identity of voters using the tokens and stores them in the interplanetary file system (IPFS). The proposed system provides the storage of tokens and verification of tokens during various stages of polling. The proposed system implemented using the IPFS, as well as the Elliptic Curve Digital Signature Algorithm (ECDSA) for the digital signature, and verification, and SHA-256 as a cryptographic hash. IPFS is used to store data in a distributed manner using the connected nodes in the network. In the proposed system, we use Go IPFS to store the files in Distributed Ledger Technology (DLT). IPFS can store any large file within any format. By splitting the user identity files, we can secure the data and privacy of voters in the Blockchain electronic voting system.
Internet Traffic Analysis and Secure E-voting
Advanced Steganography and Watermarking Techniques
Mwrwan Abubakar, Zakwan Jaroucheh, Ahmed Al Dubai, Bill Buchanan
The Session Initiation Protocol (SIP) is the principal signalling protocol in Voice over IP (VoIP) systems, responsible for initialising, terminating, and maintaining sessions amongst call parties. However, the problem with the SIP protocol is that it was not designed to be secure by nature as the HTTP digest authentication used in SIP is insecure, making it vulnerable to a variety of attacks. The current solutions rely on several standardised encryption protocols, such as TLS and IPsec, to protect SIP registration messages. However, the current centralised solutions do not scale well and cause algorithm overload when encoding and decoding SIP messages. In trying to rectify this issue, we propose in this paper a blockchain-based lightweight authentication mechanism, which involves a decentralised identity model to authenticate the SIP client to the SIP server. Our mechanism uses a smart contract on the Ethereum blockchain to ensure trust, accountability and preserves user privacy. We provided a proof-of-concept implementation to demonstrate our work. Further analysis of this approach's usability, mainly CPU and memory usage, was conducted comparing to IPsec and TLS. Then we discussed our system's security and presented a security analysis. Our analysis proves that our approach satisfies the SIP protocol security requirements.
Mustafa Kara, Muhammed Ali Aydın, Hasan H. Balık
Peer-to-peer VoIP applications are exposed to threats in the Internet environment as they carry out conversations over the Internet, which is an electronic communication line, and its security has always been largely a matter of concern. Authentication of the caller is the first line of defense among the security principles and is an important principle to provide security in VoIP application. Authentication methods in VoIP applications are usually based on trusted third parties or through centralized architecture. This situation creates problems in terms of single point of failure and privacy in call security over IP based communications. However, blockchain technology with a distributed architecture offers an innovative solution to multimedia communication authentication model. In this paper, a blockchain-based mutual authentication scheme for VoIP applications is proposed. In addition, the model's having a comprehensive security structure against various threats is explained via security and communication cost analysis. The proposed schema shows better performance than the methods that make a verification through the centralized architecture in the literature. The proposed model has been formally verified using the AVISPA tool, and it has been proven that the model is safe against potential threats.
Tor hidden services are anonymous servers of unknown location and ownership who can be accessed through any Tor-enabled web browser. They have gained popularity over the years, but still suer from major usability challenges due to their cryptographicallygenerated non-memorable addresses. In response to this difficulty, in this work we introduce the Onion Name System (OnioNS), a privacy-enhanced distributed DNS that allows users to reference a hidden service by a meaningful globally-unique veriable domain name chosen by the hidden service operator. We introduce a new distributed self-healing public ledger and construct OnioNS as an optional backwards-compatible plugin for Tor on top of existing hidden service infrastructure. We simplify our design and threat model by embedding OnioNS within the Tor network and provide mechanisms for authenticated denial-of-existence with minimal networking costs. Our reference implementation demonstrates that OnioNS successfully addresses the major usability issue that has been with Tor hidden services since their introduction in 2002.
Open access
Internet Traffic Analysis and Secure E-voting
Cryptography and Data Security
Advanced Steganography and Watermarking Techniques
Cryptocurrencies based on decentralized systems, especially blockchain, are gaining popularity more than ever. Freedom advocates hail blockchain technology as a breakthrough in digital privacy and internet anonymity. Unfortunately, after recent studies conducted, it may come as a surprise that the transactions are, in fact, not always anonymous. In this short paper, the possibility of identifying a user's accounts in different cryptocurrencies given the user's portfolio of investment gained from social media is investigated. In this study, the generic elements of blockchain systems are briefly studied. In section \ref{sec:blocksim}, BlockSim which is a tool for simulating transactions, and an algorithm for answering this question is introduced.