In this paper, we analyze Shared Send Mixers (SSMs) within Cardano's Extended Unspent Transaction Output (EUTXO) model, presenting significant contributions to the understanding of UTXO-based blockchains. Firstly, we define the EUTXO SSM untangling problem and propose an algorithm to address it, along with providing an open-source implementation of the solution. Utilizing real transaction examples, we formulate and solve this problem in a systematic manner, shedding light on the intricacies of coin circulation within the Cardano blockchain. Through our analysis, we reveal insights into the usage of SSMs, including statistics on their frequency and effectiveness in untangling transactions. With this method, our findings show that 11% of transactions—as per the method—seem to involve SSMs, 83% of which enable unique untangling. Moreover, we discuss the potential application of our algorithm in enhancing address clustering results of transaction-level heuristics. Overall, our work contributes to a deeper understanding of transactional dynamics within UTXO cryptocurrencies, particularly within the context of Cardano's EUTXO model.

Many variants of (delegated) Proof-of-Stake blockchains have been introduced since 2016, among which Cardano, Algorand, and Tezos have been more widely adopted. Each of these blockchains has attempted to address the scalability and consumption issues of Proof-of-Work (PoW) blockchains from different angles. However, the economic incentives of these blockchains have raised the concern about the decentralisation level of key players, such as validators, and stakeholders, in those “expected to be decentralised” networks. In this work, we conduct an analysis of Cardano's activity and wealth concentration. For the first time, we perform a clustering of the addresses that belong to the same wallet based on existing heuristics for UTXO-like blockchains. Moreover, an analysis of reward distribution on Cardano is presented. The analysis results of this work disclose objective insights into the Cardano blockchain, including the rewards distribution, stake balance distribution, and wealth concentration.

While there are many data collection and analysis tools for Ethereum - the largest smart contract blockchain by market capitalization, development of similar tools for other smart contract blockchains is lacking. Reasons for this are non-existent standards, changing specifications d ue t o rapid development, common usage of the off-chain storage, and lack of developers. One of such blockchains is Polkadot - a layer- zero blockchain featuring a single relay chain whose role is to secure smart contract transactions on multiple other parachains. In this paper we describe a data collection pipeline for Polkadot blockchain that we then use to perform an analysis of the bow-tie structure of its transfer network over time, with special emphasis on the role of nominators and validators in this structure. We find evidence that t he Polkadot ecosystem iss lowly maturing from a system dominated by nominators and validators, both of which require some technical skill as well as willingness to bond sufficient amount of funds, into a system increasingly populated by regular users using the financial services of Polkadot.

Blockchain (BC) applications face many challenges to comply with the European General Data Protection Regulation (GDPR) i.e., enabling users to hold on to their rights for deleting or modifying their data stored on publicly accessible and immutable BCs. In this regard, this paper proposes an on-chain solution that allows for fine-grained modification (update and erasure) operations on transactions’ (TX) data fields within a BC. The proposed solution is based on a cryptographic primitive called Chameleon Hashing. Via this approach, BC users have the authority to update their data, which are addressed at the TX level with no side effects on the block or chain. By performing and storing data updates, all on-chain traceability and verifiability characteristics of the BC are preserved.

Analysis of existing work and studies lead to the observation that BIoT (Blockchain (BC) and Internet of Things (IoT) integration) faces various efficiency issues in IoT-to-BC adaption associated with (a) scalability, (b) energy efficiency, and (c) security. To solve these concerns, at the first step and via experimental analysis of multiple Distributed Applications (dApp), this paper and PhD thesis does identify key BIoT efficiency affecting metrics. In the second step, these metrics are used to design and evaluate an efficient BIoT architecture —termed as BIIT—. Extensive simulations conducted on IoT network proves that BIIT enhances the efficiency of IoT-to-BC communications even for a limiting IoT protocol such as LoRaWAN. As of the third, the design and evaluation of DLIT (Distributed Ledger (DL) for IoT daTa) is presented. DLIT offers a highly scalable and secure DL via a hybrid consensus mechanism, equipped with sharding, and IoT data modification possibilities.

The integration of Internet-of-Things (IoT) and Blockchains (BC) for trusted and decentralized approaches enabled modern use cases, such as supply chain tracing, smart cities, and IoT data marketplaces. For these it is essential to identify reliably IoT devices, since the producer-consumer trust is not guaranteed by a Trusted Third Party (TTP). Therefore, this work proposes a Know Your IoT device platform (KYoT), which enables the self-sovereign identification of IoT devices on the Ethereum BC. KYoT permits manufacturers and device owners to register and verify IoT devices in a self-sovereign fashion, while data storage security is ensured. KYoT deploys an SRAM-based (Static Random Access Memory) Physically Unclonable Function (PUF), which takes advantage of the manufacturing variability of devices' SRAM chips to derive a unique identifying key for each IoT device. The self-sovereign identification mechanism introduced is based on the ERC 734 and ERC 735 Ethereum identity standards.

This work develops an integration of Blockchains (BC) with the Internet-of-Things (IoT) using a highly constrained TelosB IoT platform based on the MSP430 processor family and CC2420 IEEE 802.15.4-compliant radio interfaces. The system is evaluated in an indoor office environment focusing on overhead and energy efficiency of BC transaction (TX) transmissions.

In Industry 4.0 (I4), the Industrial Internet of Things (I2oT) data streams are prone to significant data manipulation risks. The integration of Blockchains (BC) with I2oT may become a solution preventing from this problem. This paper provides a blockchain-agnostic Blockchain I2oT (BI2oT) architecture called BIIT that allows developing a broad range of BC applications fully integrating Internet of Things (IoT). The mechanisms introduced in BIIT aim at solutions that provide data reliability, limit the computational overhead, and enhance energy efficiency. BIIT is evaluated through real-world experimentation.

Data leaks and privacy scandals have been a growing concern of the last decade. While most traditional, i.e., centralized, online platforms require users to register with their personal data, they potentially expose the user's identity and data to be used for unintended purposes. This work proposes TradeMap as an integrated architecture, designing and enabling an online end-to-end (e2e) trading market place, while supporting anonymous management features. TradeMap addresses the Swiss Financial Market Supervisory Authority (FINMA) regulations by designing a FINMA-complaint Know Your Customer (KYC) platform. Additionally, TradeMap is based on blockchains and employs Ethereum Smart Contracts (SC). Thus, trust and anonymity between the market place and the KYC system relies on zero knowledge proof-based SCs used for user identification processes. With this management approach proposed, the user authentication is only verified within the KYC platform, providing a legally valid and fully anonymous online trading platform.

This work proposes an IoT- and Blockchain-based, distributed system, for automated measuring, storing, and monitoring of water and air quality in environments such as lakes, mountains, urban areas, or factories. Comparable state-of-the-art solutions, require human interaction to access the data or require high power consumption or space requirements, or they are based on centralized architectures. The proposed pollution monitoring system here, on one hand, employs LoRa to address the high power consumption and long-range transmission challenges of IoT protocols. On the other hand, it is designed to be fully decentralized by using the Ethereum Blockchain to store and retrieve the data recorded by IoT sensors. Thus, data integrity is provided without the need for a Trusted Third Party (TTP) and data is collected and captured automatically without any manual operations needed. Observations on the four different types of sensors for measuring Potential Hydrogen (PH), Turbidity, Carbon monoxide (CO), and Carbon dioxide (CO2), revealed a high accuracy with the expected time-lines of measurements, non-falsified experimental values collected and can be used as reliable evidence of presence of pollution.

Smart Contracts (SC) extend the applicability of Blockchains (BC) in various decentralized use cases. This work demonstrates the design and implementation of a trading application which, employs SC and Ethereum BC. This Decentralized Application (Dapp) provides flexibility in requesting user Identity (ID) directly by seller/hirer and buyers/renter. To provide trust, deposits are paid by two sides while setting up contracts. WiFi- Direct is the chosen Device to Device (D2D) communication protocol which provides high data rates and secure data transmission. Light-Weight SC are introduced in this work which, use D2D communications for sending sold or rented object's or each party's images, and ID data directly to other party instead of storing them in the public BC to reduce the costs. Evaluations in terms of D2D deployment, transaction costs, and privacy, indicate that this system is time-efficient and manages the process in a cost-efficient fashion without the need to store and publish all of the user's ID information in BC.