Burnable Pseudo-Identity: A Non-Binding Anonymous Identity Method for Ethereum

The concept of identity has become one common research topic in security and privacy where the real identity of users must be preserved, usually covered by pseudonym identifiers. With the rise of Blockchain-based systems, identities are becoming even more critical than before, mainly due to the immutability property. In fact, many publicly accessible Blockchain networks like Ethereum rely on pseudonymization as a method for identifying subject actions. Pseudonyms are often employed to maintain anonymity, but true anonymity requires unlinkability. Without this property, any attacker can examine the messages sent by a specific pseudonym and learn new information about the holder of this pseudonym. This use of Blockchain collides with regulations because of the right to be forgotten, and Blockchain-based solutions are ensuring that every data stored within the chain will not be modified. In this paper we define a method and a tool for dealing with digital identities within Blockchain environments that are compliant with regulations. The proposed method provides a way to grant digital pseudo identities unlinked to the real identity. This new method uses the benefits of key derivation systems to ensure a non-binding interaction between users and the information model associated with their identity. The proposed method is demonstated in the Ethereum context and illustrated with a case study.PoSeID-on is a project funded by the European Commission. This project has received funding from the European Union’s Horizon 2020 program under Grant Agreement n◦ 786713

Privacy-aware Biometric Blockchain based e-Passport System for Automatic Border Control

In the middle of 1990s, World Wide Web technology initially steps into our life. Now, 30 years after that, widespread internet access and established computing technology bring embodied real life into Metaverse by digital twin. Internet is not only blurring the concept of physical distance, but also blurring the edge between the real and virtual world. Another breakthrough in computing is the blockchain, which shifts the root of trust attached to a system administrator to the computational power of the system. Furthermore, its favourable properties such as immutable time-stamped transaction history and atomic smart contracts trigger the development of decentralized autonomous organizations (DAOs). Combining above two, this thesis presents a privacy-aware biometric Blockchain based e-passport system for automatic border control(ABC), which aims for improving the efficiency of existing ABC system. Specifically, through constructing a border control Metaverse DAO, border control workload can be autonomously self-executed by atomic smart contracts as transaction and then immutably recorded on Blockchain. What is more, to digitize border crossing documentation, biometric Blockchain based e-passport system(BBCVID) is created to generate an immutable real-world identity digital twin in the border control Metaverse DAO through Blockchain and biometric identity authentication. That is to say, by digitizing border crossing documentation and automatizing both biometric identity authentication and border crossing documentation verification, our proposal is able to significantly improve existing border control efficiency. Through system simulation and performance evaluation by Hyperledger Caliper, the proposed system turns out to be able to improve existing border control efficiency by 3.5 times more on average, which is remarkable. What is more, the dynamic digital twin constructed by BBCVID enables computing techniques such as machine learning and big data analysis applicable to real-world entity, which has a huge potential to create more value by constructing smarter ABC systems

Hajusraamatutehnoloogia kasutuselevõtu õiguslikud takistused: tehnoloogia neutraalsuse ja funktsionaalse samaväärsuse põhimõtetele tuginev analüüs

Väitekirja elektrooniline versioon ei sisalda publikatsiooneKäesolev väitekiri käsitleb hajusraamatutehnoloogia (HT) kohtlemist Eesti ja EL õiguse alusel konkreetsete kasutusjuhtude näitel. HT on “mitmeotstarbeline tehnoloogia”, millel on rida erinevaid kasutusvõimalusi, sh. selle kõige tuntumad näited nagu plokiahelatehnoloogia ning bitimünt. Kuivõrd olemasolev õigusraamistik on loodud tsentraliseeritud infrastruktuuride ning mitte hajutatud andmestruktuuride jaoks nagu seda on HT, siis tihtipeale takistab olemasolev õigusraamistik HT kasutamist selles sisalduvate nii otseste kui ka kaudsete kallutatud nõuete tõttu. Nimetatud dissonants on sarnane analoogmaailma jaoks loodud õigusnormide takistava mõjuga digitaalsete lahenduste kasutuselevõtmisel. Seega ei ole väitekirjas käsitletavad takistused vaid HT-le omased vaid seotud iga uue tehnoloogia kasutuselevõtuga. Toodud probleemi uuritakseväitekirjas kolme konkreetse HT kasutusjuhu pinnal: (i) bitimündi vahetusteenuse osutamine; (ii) HT-põhise osanike nimekirja pidamine ; (iii) HT-põhise hübriid-targa lepingu ning elektroonilise allkirja kasutamine. Uurimise mõõdupuuna kasutatakse tehnoloogia neutraalsuse põhimõtet ning funktsionaalse samaväärsuse alampõhimõtet, et tuvastada kallutatud nõudeid ning piirata riigivõimu voli eelistada konkreetseid tehnoloogiaid samas teisi tehnoloogiaid diskrimineerides. HT kasutusjuhtude pinnal saab järeldada, et olemasolev õigsraamistik ei ole tehnoloogia-neutraalne ning eelistab tsentraliseeritud lahendusi ning ei taga HT-põhistele funktsionaalselt samaväärsetele lahendustele samaväärset kohtlemist. Arvestades toodud järeldusi uuritakse väitekirjas ka kallutatud nõuete põhjuseid ning strateegiaid kuidas jätkusuutlikult lahendada kallutatusest tekkinud takistused HT kasutusele. Väitekirja teema on oluline arvestades ka 2020. aasta lõpus avaldatud EL-i digitaalse finantspaketi määruste eesmärki, milleks on toetada HT kasutuselevõttu EL-is.This dissertation focuses on the treatment of distributed ledger technology (DLT) applications under the existing regulation in Estonia and the EU based on the analysis of specific use cases. The existing regulatory frameworks in most jurisdictions were built for centralized infrastructures and not for distributed ones, such as built on DLT. Consequently, current legal frameworks may inhibit the use of DLT due to either apparent or non-apparent biases written into the regulation. DLT on the other hand represents a “general-purpose technology” that, therefore, has abundance of applications including its most well known examples of blockchain and Bitcoin. The discrepancy between old rules and new tools is nothing new as the development of the digital world in comparison to the physical world led to the same problem. Therefore, the research problem addressed in the dissertation is not specific to DLT, but linked to the uptake of any new technology. With the aim to explore the potentially inhibiting effect of existing regulation, specific DLT use cases are investigated: (i) bitcoin exchange-service provision; (ii) DLT-based shareholder ledger maintenance and (iii) use of DLT-based electronic signature and hybrid smart contract agreements. In this exploration, the principle of technology neutrality and its sub-principle of functional equivalence are utilized as benchmarks for the identification of biases. The aim of these principles is to prohibit regulators from favouring some technologies and discriminating against others. The use case analyses show that some of the existing regulation is not technology-neutral due to inbound bias for centralized solutions. Furthermore, effects equivalence is not granted by existing regulation to functionally equivalent DLT-based solutions. Against this background, the dissertation discusses the reasons for these biases and regulative strategies to resolve these in a sustainable manner. The dissertation is especially relevant considering the goal of the proposed EU regulations of the Digital Finance Package introduced in late 2020 to promote the use of DLT in the EU.https://www.ester.ee/record=b542731

Cybersecurity applications of Blockchain technologies

With the increase in connectivity, the popularization of cloud services, and the rise of the Internet of Things (IoT), decentralized approaches for trust management are gaining momentum. Since blockchain technologies provide a distributed ledger, they are receiving massive attention from the research community in different application fields. However, this technology does not provide cybersecurity by itself. Thus, this thesis first aims to provide a comprehensive review of techniques and elements that have been proposed to achieve cybersecurity in blockchain-based systems. The analysis is intended to target area researchers, cybersecurity specialists and blockchain developers. We present a series of lessons learned as well. One of them is the rise of Ethereum as one of the most used technologies. Furthermore, some intrinsic characteristics of the blockchain, like permanent availability and immutability made it interesting for other ends, namely as covert channels and malicious purposes. On the one hand, the use of blockchains by malwares has not been characterized yet. Therefore, this thesis also analyzes the current state of the art in this area. One of the lessons learned is that covert communications have received little attention. On the other hand, although previous works have analyzed the feasibility of covert channels in a particular blockchain technology called Bitcoin, no previous work has explored the use of Ethereum to establish a covert channel considering all transaction fields and smart contracts. To foster further defence-oriented research, two novel mechanisms are presented on this thesis. First, Zephyrus takes advantage of all Ethereum fields and smartcontract bytecode. Second, Smart-Zephyrus is built to complement Zephyrus by leveraging smart contracts written in Solidity. We also assess the mechanisms feasibility and cost. Our experiments show that Zephyrus, in the best case, can embed 40 Kbits in 0.57 s. for US$1.64, and retrieve them in 2.8 s. Smart-Zephyrus, however, is able to hide a 4 Kb secret in 41 s. While being expensive (around US$ 1.82 per bit), the provided stealthiness might be worth the price for attackers. Furthermore, these two mechanisms can be combined to increase capacity and reduce costs.Debido al aumento de la conectividad, la popularización de los servicios en la nube y el auge del Internet de las cosas (IoT), los enfoques descentralizados para la gestión de la confianza están cobrando impulso. Dado que las tecnologías de cadena de bloques (blockchain) proporcionan un archivo distribuido, están recibiendo una atención masiva por parte de la comunidad investigadora en diferentes campos de aplicación. Sin embargo, esta tecnología no proporciona ciberseguridad por sí misma. Por lo tanto, esta tesis tiene como primer objetivo proporcionar una revisión exhaustiva de las técnicas y elementos que se han propuesto para lograr la ciberseguridad en los sistemas basados en blockchain. Este análisis está dirigido a investigadores del área, especialistas en ciberseguridad y desarrolladores de blockchain. A su vez, se presentan una serie de lecciones aprendidas, siendo una de ellas el auge de Ethereum como una de las tecnologías más utilizadas. Asimismo, algunas características intrínsecas de la blockchain, como la disponibilidad permanente y la inmutabilidad, la hacen interesante para otros fines, concretamente como canal encubierto y con fines maliciosos. Por una parte, aún no se ha caracterizado el uso de la blockchain por parte de malwares. Por ello, esta tesis también analiza el actual estado del arte en este ámbito. Una de las lecciones aprendidas al analizar los datos es que las comunicaciones encubiertas han recibido poca atención. Por otro lado, aunque trabajos anteriores han analizado la viabilidad de los canales encubiertos en una tecnología blockchain concreta llamada Bitcoin, ningún trabajo anterior ha explorado el uso de Ethereum para establecer un canal encubierto considerando todos los campos de transacción y contratos inteligentes. Con el objetivo de fomentar una mayor investigación orientada a la defensa, en esta tesis se presentan dos mecanismos novedosos. En primer lugar, Zephyrus aprovecha todos los campos de Ethereum y el bytecode de los contratos inteligentes. En segundo lugar, Smart-Zephyrus complementa Zephyrus aprovechando los contratos inteligentes escritos en Solidity. Se evalúa, también, la viabilidad y el coste de ambos mecanismos. Los resultados muestran que Zephyrus, en el mejor de los casos, puede ocultar 40 Kbits en 0,57 s. por 1,64 US$, y recuperarlos en 2,8 s. Smart-Zephyrus, por su parte, es capaz de ocultar un secreto de 4 Kb en 41 s. Si bien es cierto que es caro (alrededor de 1,82 dólares por bit), el sigilo proporcionado podría valer la pena para los atacantes. Además, estos dos mecanismos pueden combinarse para aumentar la capacidad y reducir los costesPrograma de Doctorado en Ciencia y Tecnología Informática por la Universidad Carlos III de MadridPresidente: José Manuel Estévez Tapiador.- Secretario: Jorge Blasco Alís.- Vocal: Luis Hernández Encina

Comparison of Blockchain technology in various segments of supply chain management

Blockchain technology promises to disrupt existing business processes by replacing existing centralized systems. Blockchain technology has gotten plenty of attention in the past few years. The interest in the new technology has reached logistics and supply chain management. When blockchain technology is implemented successfully it can bring benefits such as cost savings, better visibility, and better efficiency. Businesses could greatly benefit from these matters and get competitive advantage if they succeed to implement blockchain technology successfully before their competitors. There are various blockchain platforms available and new platforms are created continuously. These platforms can differ greatly from each other in terms of performance, scalability, and privacy. When considering implementing blockchain technology to supply chains it is key to choose a platform which has the best match to the particular use case. There is earlier research done about different blockchain platforms in different applications, but it is hard to get a bigger picture difference of blockchain platforms in supply chain applications from single studies. This research combines earlier research of the topic using qualitative meta-synthesis. The aim of the study is to find out the differences between Hyperledger Fabric, Ethereum, Corda, Multichain, and Bitcoin platforms. Study found big differences in the suitability to supply chain applications between the platforms. It is key to understand comprehensively the needs for the platform before any decisions between platforms are made, because choosing between these platforms is a tradeoff. The result of the study was that Hyperledger Fabric shoved the best results in most use cases. The biggest challenge in this thesis was to find relevant information because the technology is relatively new.Blockchain teknologialla on mahdollisuus häiritä olevia liiketoimintaprosesseja korvaamalla nykyiset keskitetyt järjestelmät. Lohkoketju teknologia on saanut yhä enemmissä määrin huomiota viime vuosina. Kiinnostus uutta teknologiaa kohtaan on saavuttanut logistiikan ja toimitusketjun hallinnan. Jos lohkoketju teknologia pystytään implementoimaan onnistuneesti, se voi tuoda etuja, kuten kustannussäästöjä ja parempaa tehokkuutta. Tämä voisi suuresti hyödyttää yrityksiä, jos ne onnistuvat ottamaan lohkoketju teknologian käyttöön onnistuneesti ennen kilpailijoitaan. Jo nykyisin saatavilla on erilaisia lohkoketju alustoja ja uusia alustoja luodaan jatkuvasti. Nämä alustat voivat erota suuresti toisistaan muun muassa suorituskyvyn, skaalautuvuuden ja yksityisyyden suhteen. Kun harkitaan lohkoketju teknologian käyttöönottoa toimitusketjuissa, on tärkeää valita alusta, joka sopii parhaiten omaan käyttötarkoitukseen. Eri sovelluksissa eri lohkoketju alustoista on tehty aiemminkin tutkimuksia, mutta yksittäisistä tutkimuksista on vaikea saada suurempaa kuvaa lohkoketju alustojen eroista toimitusketju sovelluksissa. Tämän tutkimuksen tarkoituksena on tutkia metasynteesi tutkimusmenetelmää hyödyntäen Hyperledger Fabric-, Ethereum-, Corda-, Multichain- ja Bitcoin- alustojen eroavaisuuksia. Tutkimuksessa havaittiin suuria eroja alustojen välillä soveltuvuudessa toimitusketju sovelluksiin. On tärkeää ymmärtää kokonaisvaltaisesti omat tarpeet alustalle ennen päätöksiä alustojen välillä, sillä valinta on kompromissi alustojen eroavaisuuksista johtuen. Tutkimuksen tuloksena havaittiin, että Hyperledger Fabric saavutti parhaat tulokset useimmissa käyttötapauksissa. Suurin haaste tässä opinnäytetyössä oli olennaisen tiedon löytäminen, koska tekniikka on suhteellisen uutta

A business process model for blockchain-based South African real estate transactions

The real estate transaction process has been described as inefficient and technologically outdated due to numerous stakeholders and predominantly paper-based operations. Despite the apparent bottlenecks in the current process, the implementation of new technology into the real estate sector has lagged. Several attempts have been made to modernise and digitise the business process but committed integration of assisting technology has lacked attention. This study examined the applicability and potential integration of blockchain technology into the business process of South African real estate transactions. Blockchain’s novelty means that research in this space, especially within South Africa, is limited. Of the research that has been conducted, no models of the business processes for South African or blockchain-based real estate transactions have been constructed. This study provides two business process models, illustrating the two different processes. The main contribution of this paper was an integrated business process model, illustrating how the various processes and stakeholder interactions for South African blockchain-based real estate transactions are conducted on one transaction platform, common to all participating stakeholders. This platform was named the South African Blockchain Land Exchange System (SABLES), which manages and facilitates these transactions in their entirety from start to finish. This model depicts an enhanced business process that provides increased security, transparency, and speed. These benefits will be realised by those who register, adopt, and transact on the platform. Through in-depth interviews, the integrated business process model was assessed. The findings produced a final and combined thematic map, representing the main themes of the analysed interview data, namely blockchain implementation strategies, business process applicability, information technology assimilation, current transaction context, and PropTech 3.0 success factors. The discussion revealed that the current transaction process lacks technological innovation, which increases pressure on the conveyancing role. It was also revealed that there is not only a need within the industry, but a desire, for newer technologies to assist the transaction process. In order to streamline and improve efficiency, business processes should leverage digital records and data, and strive for a solution beyond digitisation, achieving digitalisation. Digitalisation recognises digital documents as official and legal documents as opposed to simply being digital back-ups. This, coupled with the business process models, represent theoretical contributions