The basis of blockchain-related data, stored in distributed ledgers, are digitally signed transactions. Data can be stored on the blockchain ledger only after a digital signing process is performed by a user with a blockchain-based digital identity. However, this process is time-consuming and not user-friendly, which is one of the reasons blockchain technology is not fully accepted. In this paper, we propose a machine learning-based method, which introduces automated signing of blockchain transactions, while including also a personalized identification of anomalous transactions. In order to evaluate the proposed method, an experiment and analysis were performed on data from the Ethereum public main network. The analysis shows promising results and paves the road for a possible future integration of such a method in dedicated digital signing software for blockchain transactions.

The main purpose of supply chain systems based on blockchain technology is to take advantage of technology innovations to ensure that a tracked asset’s audit trail is immutable. However, the challenge lies in tracking the asset among different blockchain-based supply chain systems. The model proposed in this paper has been designed to overcome the identified challenges. Specifically, the proposed model enables: (1) the asset to be tracked among different blockchain-based supply-chain systems; (2) the tracked asset’s supply chain to be cryptographically verified; (3) a tracked asset to be defined in a standardized format; and (4) a tracked asset to be described with several different standardized formats. Thus, the model provides a great advantage in terms of interoperability between different blockchain-driven supply chains over other models in the literature, which will need to replicate the information in each blockchain platform they operate with, while giving flexibility to the platforms that make use of it and maintain the scalability of those logistic platforms. This work aims to examine the application of the proposed model from an operational point of view, in a scenario within the pharmaceutical sector.

Blockchain technology enables the creation of a decentralized and distributed environment in which transactions and data are not controlled by a central authority. Simultaneously transactions are secure, ubiquitous and trustworthy due to the used cryptographic principles. In this paper, we present a global decentralized blockchain-based platform and ecosystem called EduCTX. The platform enables managing, assigning and presenting credentials for individuals and educational institutions as well as other potential stakeholders such as companies, institutions and organizations. Further it enables the development of own digital services, which offers organizations the opportunity to automate the evaluation of individuals' skills and knowledge. The EduCTX platform is implemented on the blockchain platform Ethereum on a consortium-based network of Ethereum run nodes. The platform enables a globally efficient, simplified and ubiquitous environment to avoid language and administrative barriers.

Blockchain technology is increasingly being considered among both private enterprises and public services. However, it poses a challenge with regard to aligning its identity management scheme with the Public Key Infrastructure and the Qualified Digital Certificates issued by Qualified Trust Service Providers. To solve this challenge, we will present a solution in the form of an architecture reference model, which enables enterprises and public services to leverage blockchain technology by integrating Qualified Electronic Signatures with blockchain transactions. The evaluation of the architecture reference model is provided through the design of a Blockchain-based Trusted Public Service and a use-case scenario example. The proposed architecture reference model is based on the CEF building blocks EBSI, eSignature, and eID compliant with eIDAS.

Currently, developers and researchers are dedicated to finding better ways to achieve greater scalability of various blockchain platforms. Focused on the Ethereum blockchain platform, the state channels are currently the only maturely researched and implemented a solution for achieving scalability. However, there are still several problems, such as transparency of state channel networks, transaction traceability, and the incapability that the off-chain state is transferred back on the blockchain network in an ad-hoc manner. To solve the aforementioned problems, we propose a novel state channel solution in the form of a State Channel as a Service, which, although off-chain, still incorporates a secure distributed and decentralized network. This solves the challenge of transparency and traceability while giving users the confidence that only the valid last off-chain state is transferred back on the blockchain network. With the proposed solution, there is no need for users to monitor state channel activities for possible malicious actions. Implementation was performed in the form of a payment channel system, presenting a potential use case for the SCaaS. Furthermore, we performed a security and performance analysis, which shows that the solution is secure and by a factor of 12 more efficient than the classical on-chain payment systems. To evaluate and prove the contributions of the proposed solution, quantitative, and qualitative comparisons with selected related works (i.e., Raiden and Celer) were also performed.