Throughout the history of mankind, trusted relationships have played a vital part in every \ntransaction humans have made. Those transactions belong to a spectrum that starts from \neveryday life decisions and acts, to a more complex, sensitive and wide area that even nations \nare involved. \nBefore the era of globalization of telecommunications that we live in, achieving trust was \nmore related to human relations. Even though that the meaning of trust is known to all, it is \nhard to find a definition that strictly describes it. \nTrust is multidimensional, multidisciplinary and multifaceted concept. Many definitions can \nbe found in literature and are related to notions as goodness, strength, reliability, integrity, \nability or character of a person or thing. A trust relationship involves two parties, a trustor \nand a trustee. The trustor is the person that holds confidence, belief on the reliability of \nanother person or thing which is the other party, the trustee. (Zheng & Valtteri Niemi, \nTowards User Driven Trust Modeling and Management, 2009) \nHow though trust is established in modern computer networks, where the notions of the \ntrustor and trustee are not represented by strictly humans, but from entities that might never \nhave had a relationship upon the trust can be build. \nIn this project we will study the achievement of trust in traditional kinds of networks such as \nad-hoc, mobile and wireless and we will examine the ability to elevate the trust level in a \ncomputer network using the under development and mostly promising blockchain network. \nThe network is going to be setup as a private blockchain network, where all the nodes that \nconsist it, will be pre-set from an administrative team. The computers that will participate will \nhave all the requirements in order to connect to the private network running as services on \nboot. \nThe application will run on each node and on starting the application the very first check will \nbe to start the node and connect to the network. Only if the network has been found and the \nnode is connected to it, the application proceeds with checking the presence of web3js and \nonly after successfully checking the communication of the web3js with the network, the user \nis prompt with the login page. \nThe authorization of the user is checked upon a smart contract on the blockchain network \nand after a successfully prompt from the smart contract, the credentials are checked, in our \ncase, on a fake backend where a JWT token is issued to the user in order to use the application \ndepending on the role that he has.
Cryptocurrencies are a cryptography based technology, that has increased massively in popularity in recent years. These currencies are traded on markets that specialize in cryptocurrency trade. There, you can trade one cryptocurrency for another, or buy one with real world money. These markets are quite volatile, meaning that the price of most cryptocurrencies swing up and down a lot. The largest cryptocurrency is Bitcoin, but there is also more than 1500 smaller ones, that goes by the name alternative coins, or altcoins. This thesis will try to find out if it is possible to make accurate predictions about the future price of the altcoin Ethereum, and also see if Bitcoin may have some influence over the price of the selected altcoin. The predictions were made with the use of an artificial neural network, an LSTM network, that was trained on labeled data from 2017. The predictions were then made in intervals of one hour ahead, six hours ahead, and one day ahead through early 2018. The predictions showed that it is possible to make somewhat accurate predictions about the future. The predictions that were made one hour ahead were more accurate than both the six hours ahead predictions and the full day ahead predictions. By comparing the loss rates of the neural networks that were only trained on Ethereum, with the loss rates of the networks that trained on both Bitcoin and Ethereum, is was made clear that training on both cryptocurrencies did not improve the prediction accuracies.
Exchanging personal information for access to a service has become an integral part of everyday life. Surprisingly often, we do not even realize that this exchange is taking place. When accepting the terms of service agreement of a company, it is often unclear what is happening to (personal) data. Unknowingly, users had out blank cheques to companies, allowing them to control and resell the their data. The General Data Protection Regulation (GDPR), which became enforceable in May 2018, is a first step towards putting users back in control of their personal data. With these new regulations, the existing solutions for consent management are not feasible any more for a data marketplace as well as for most consent scenarios. Utilizing the Design Science Research (DSR) methodology, this master thesis aims to create a prototype of a consent management system on the Ethereum Blockchain. With this prototype, we envision a data marketplace scenario which enables users to control their data.
The scandal around Facebook and Cambridge Analytica in 2017 showed drastically that new concepts to share andstore information need to be developed in order to minimize the huge potential for abuse resulting from centralized information stored at trusted third parties. This thesis analysed to what degree current document exchange systems (e.g. Dropbox) comply with the information security services confidentiality, integrity, privacy, anonymity, authenticity of authors, non-repudiation, and accountability; with the result that all analysed systems lack support for privacy and anonymity. Mainly due to their centralized design, missing (meta)data encryption, and regulations of jurisdictions in which they operate. Based on that analysis a decentralized concept for document sharing in a peer-to-peer fashion utilising client-side encryption, the separation of data and metadata, metadata masking through Tor hidden services, and distributed ledger technology for directory service provision, was developed. The concept was proven through prototype implementation of a document exchange software called docShare and its information security services were compared with former analysed exchange technologies. The analysis showed that docShare has a better information security service provision but is still leaking identity information in form of IPad dresses when interacting with the distributed ledger Ethereum. Mainly because Ethereum doesnât support traffic anonymization through Tor.
Background: Past few months have seen the rise of blockchain and cryptocurrencies. In this context, the Ethereum platform, an open-source blockchain-based platform using Ether cryptocurrency, has been designed to use smart contracts programs. These are self-executing blockchain contracts. Due to their high volume of transactions, analyzing their behavior is very challenging. We address this challenge in our paper. Methods: We develop for this purpose an innovative approach based on the non-negative tensor decomposition Paratuck2 combined with long short-term memory. The objective is to assess if predictive analysis can forecast smart contracts activities over time. Three statistical tests are performed on the predictive analytics, the mean absolute percentage error, the mean directional accuracy and the Jaccard distance. Results: Among dozens of GB of transactions, the Paratuck2 tensor decomposition allows asymmetric modeling of the smart contracts. Furthermore, it highlights time dependent latent groups. The latent activities are modeled by the long short term memory network for predictive analytics. The highly accurate predictions underline the accuracy of the method and show that blockchain activities are not pure randomness. Conclusion: Herein, we are able to detect the most active contracts, and predict their behavior. In the context of future regulations, our approach opens new perspective for monitoring blockchain activities.
Yanqi Zhao, Yannan Li, Qilin Mu, Bo Yang · 5 authors
The cyber physical system (CPS) has gained considerable success in large-scale distributed integration environment. In such systems, the sensor devices collect data which would be disseminated via reliable manner to all interested co-operant entities from the physical world. However, highly unreliable environment of CPS, for example, a number of limitations of existing network middle wares, makes secure and reliable data distribution services a challenge issue. In this paper, we propose a new architecture called secure pub-sub (SPS) without middle ware, i.e., blockchain-based fair payment with reputation. In SPS, publishers publish a topic on the blockchain and subscribers specify an interest message by making a deposit to subscribing the topic. Then, if the interest message matches the topic, the publisher transmits the encrypted content of the topic to the blockchain such that the subscribers can decrypt the ciphertext to obtain the content, and mark the publisher as its reputation. Finally, the publisher receives the payment from the subscriber. The new proposal provides confidentiality and reliability of data, anonymity of subscribers and payment fairness between the publishers and subscribers. Different from the traditional pub-sub services, no trusted third party is involved in our system due to employing blockchain technique. The security of the proposed SPS is analyzed as well. The implementation of the protocol on Ethereum of smart contract demonstrates the validity of SPS.
In the past years, the security of Bitcoin-like protocols has been intensively studied. However, previous investigations are mainly focused on the single-mode version of Bitcoin protocol, where the protocol is running among full nodes (miners). In this paper we initiate the study of multi-mode cryptocurrency protocols. We generalize the recent framework by Garay et al (Eurocrypt 2015) with new security de nitions that capture the security of realistic cryptocurrency systems. e.g. Bitcoin with full and lightweight nodes. As an immediate application of our new framework, we analyze the security of existing blockchain pruning proposals for Bitcoin and Ethereum aiming to improve the storage e ciency of network nodes by pruning unnecessary information from the ledger.
Joseph Wall, D. Larry Crumbley, Lewis B. Kilbourne, Caleb Blair
In this report, the authors discuss cryptocurrencies â especially bitcoin â and argue that because the IRS lists them as property, they are taxable, and because they are not as anonymous as once thought, they are not free from fraud. Cryptocurrencies are digital assets used as a medium of exchange, but they are not really coins. They can be sent electronically from one entity to another almost anywhere in the world with an internet connection. There are many cryptocurrencies in the market, including bitcoin, ethereum, ethereum classic, litecoin, nem, dash, iota, bitshares, monero, neo, and ripple. Many of the cryptocurrency networks are not controlled by a single entity or company; instead, a decentralized network of computers keeps track of the currency using a token ID. A ledger maintains a continuously growing list of date stamped transactions in real time called âblocks.â This technology is known as blockchain, which records, verifies, and stores transactions without a trusted central authority. The network instead relies on decentralized autonomous organizations (DAOs) with uncertain legal standing.
Since it is dicult to protect servers from high-volume scraping, a new wayto reduce excessive requests is needed. Using rougher methods such as ratelimit or IP control mechanisms are not sucient. I ...
Blockchain Technology Applications and Security
Advanced Steganography and Watermarking Techniques
This thesis uses blockchain technology to construct a decentralized application (often
called a âĂappâ) for the sake of verifying results of a matching algorithm used on
data in the automotive industry. Its main intent is to explore whether the framework
Ethereum can be utilized to aid in ensuring the correctness of client responses to a
query sent by a peer in the network. The application was programmed in Solidity
and JavaScript, and run on a local test network consisting of five clients. Testing the
finished application showed that the throughput of data was slow, approximately
35 bytes/s, and that taking over the network to send corrupted information was
relatively simple. These findings, along with a general study of the areas where
blockchain technology is most advantageous, led to the conclusion that though it
has potential as a constituent in the car industry, it is not suitable for verification
of matchings at the time of writing.
The problem of scalability of blockchain platforms has raised a considerable amount of attention in the recent months. With the rise of the use of blockchain platforms and the prices of various cryptocurrencies hitting an all-time high in December of 2017, blockchain has now entered the eyes of the general public. Often seen as the future of digital transactions and applications, the decentralized platform faces many struggles in building networks capable of supporting the vast number of financial transactions modern systems currently handle, let alone serving as a replacement for the client-server model of the Internet. This paper introduces the basic structure of blockchain platforms that exist today, introduces the scalability problem, and examines the solutions that developers have proposed or implemented.
Metcalfeâs law states that the value of a network is proportional to the square of its total number of users. ERC-20 is a smart contract standard for tokens that run on the Ethereum blockchain. In ...
Distributed ledger technologies (DLTs) are currently dominating the field of distributed systems research and development. The Ethereum blockchain is emerging as a popular DLT platform for developing software and applications. Several challenges in Ethereum software development are the complex nature of working with DLTs, the lack of tools for developing on this DLT, and poor documentation of concepts for DLT developers. In this thesis, we provide building blocks that reduce the complexity of DLT operations and lower the barrier to entry into DLT development. We do this by providing a Node.js library, Ethereum-Easy, that simplifies operations on Ethereum. We implement this library into a sample application called Rock, Paper, Scissors (RPS) and built a continuous delivery, continuous integration pipeline for deploying Ethereum code (Jenk-Thereum). This thesis aims to make development on DLTs easier, quicker, and less expensive.
Gaby G. Dagher, Praneeth Babu Marella, Matea Milojkovic, Jordan Mohler
Voting is a fundamental part of democratic systems; it gives individuals in a community the faculty to voice their opinion. In recent years, voter turnout has diminished while concerns regarding integrity, security, and accessibility of current voting systems have escalated. E-voting was introduced to address those concerns; however, it is not cost-effective and still requires full supervision by a central authority. The blockchain is an emerging, decentralized, and distributed technology that promises to enhance different aspects of many industries. Expanding e-voting into blockchain technology could be the solution to alleviate the present concerns in e-voting. In this paper, we propose a blockchain-based voting system, named BroncoVote, that preserves voter privacy and increases accessibility, while keeping the voting system transparent, secure, and cost-effective. BroncoVote implements a university-scaled voting framework that utilizes Ethereumâs blockchain and smart contracts to achieve voter administration and auditable voting records. In addition, BroncoVote utilizes a few cryptographic techniques, including homomorphic encryption, to promote voter privacy. Our implementation was deployed on Ethereumâs Testnet to demonstrate usability, scalability, and efficiency.
Open access
Blockchain Technology Applications and Security
Internet Traffic Analysis and Secure E-voting
Advanced Steganography and Watermarking Techniques
With the widespread of E-commerce, the need of a trusted system to ensure the delivery of traded items is crucial. Current proof of delivery (PoD) systems lacks transparency, traceability, and credibility. These systems are mostly centralized and rely on trusted third parties (TTPs) to complete the delivery between sellers and buyers. TTPs can be costly, a single point of failure, and subject to hacking, privacy evasion, and compromise. The blockchain is an immutable, trusted, and decentralized ledger with logs and events that can be used for transparency, traceability, and tracking. In this paper, we present a solution and a general framework using the popular permissionless Ethereum blockchain to create a trusted, decentralized PoD system that ensures accountability, auditability, and integrity. The solution uses Ethereum smart contracts to prove the delivery of a shipped item between a seller and a buyer irrespective of the number of intermediate transporters needed. In our proposed solution, all participating entities are incentivized to act honestly by using a double deposit collateral. Automated payment in ether is an integral part of a solution to ensure that every entity gets its intended share of ether upon successful delivery. An arbitration mechanism is also incorporated if a dispute arises during the shipping process. In this paper, we show how we implemented, verified, and tested the proper functionality of our PoD solution. We also provide security analysis and give estimates of the cost consumption in ether gas. We made the full code of the Ethereum smart contracts publicly available at Github.
In recent years, with the rapid development and popularization of BitCoin, the research of blockchain technology has also shown growth. It has gradually become a new generation of distributed, non-centralized and trust-based technology solution. However, the blockchain operation is expensive and transaction is delayed. Take BitCoin as an example. On the one hand, a block is produced every ten minute. On the other hand, once the new block is generated, it takes a certain time to propagate world wide. The slow speed of propagation determines that BitCoin can not use too small block interval time. Ethereum also faces similar problems, so the concept of uncle block was introduced to reduce blockchain forks. This paper introduces a new tree structure based broadcast propagation routing model, providing a novel method to organize network nodes and message propagation mechanism. In oder to avoid the single node failure problem, the tree cluster routing is proposed. The research shows that the tree based routing can accelerate broadcast convergence time and reduce redundant traffic.