A blockchain based approach for the definition of auditable Access Control systems

This work proposes to exploit blockchain technology to define Access Control systems that guarantee the auditability of access control policies evaluation. The key idea of our proposal is to codify attribute-based Access Control policies as smart contracts and deploy them on a blockchain, hence transforming the policy evaluation process into a completely distributed smart contract execution. Not only the policies, but also the attributes required for their evaluation are managed by smart contracts deployed on the blockchain. The auditability property derives from the immutability and transparency properties of blockchain technology. This paper not only presents the proposed Access Control system in general, but also its application to the innovative reference scenario where the resources to be protected are themselves smart contracts. To prove the feasibility of our approach, we present a reference implementation exploiting XACML policies and Solidity written smart contracts deployed on the Ethereum blockchain. Finally, we evaluate the system performances through a set of experimental results, and we discuss the advantages and drawbacks of our proposal

Towards Blockchain-Based Identity and Access Management for Internet of Things in Enterprises

With the Internet of Things (IoT) evolving more and more, companies active within this area face new challenges for their Identity and Access Management (IAM). Namely, general security, resource constraint devices, interoperability, and scalability cannot be addressed anymore with traditional measures. Blockchain technology, however, may act as an enabler to overcome those challenges. In this paper, general application areas for blockchain in IAM are described based on recent research work. On this basis, it is discussed how blockchain can address IAM challenges presented by IoT. Finally, a corporate scenario utilizing blockchain-based IAM for IoT is outlined to assess the applicability in practice. The paper shows that private blockchains can be leveraged to design tamper-proof IAM functionality while maintaining scalability regarding the number of clients and transactions. This could be useful for enterprises to prevent single-point-of-failures as well as to enable transparent and secure auditing & monitoring of security-relevant events

Blockchain 3.0 applications survey

In this paper we survey a number of interesting applications of blockchain technology not related to cryptocurrencies. As a matter of fact, after an initial period of application to cryptocurrencies and to the financial world, blockchain technology has been successfully exploited in many other different scenarios, where its unique features allowed the definition of innovative and sometimes disruptive solutions. In particular, this paper takes into account the following application scenarios: end-to-end verifiable electronic voting, healthcare records management, identity management systems, access control systems, decentralized notary (with a focus on intellectual property protection) and supply chain management. For each of these, we firstly analyse the problem, the related requirements and the advantages the adoption of blockchain technology might bring. Then, we present a number of relevant solutions proposed in the literature both by academia and companies

Exploiting Blockchain Technology for Attribute Management in Access Control Systems

Access Control systems are a key resource in computer security to properly manage the access to digital resources. Blockchain technology, instead, is a novel technology to decentralise the control and management of a shared state, representing anything from a data repository to a distributed virtual machine. We propose to integrate traditional Access Control systems with blockchain technology to allow the combined system to inherit the desirable properties blockchain technology provides, mainly transparency and, consequently, auditability. Depending on the application scenario considered, for some systems it may not be desirable to employ a fully decentralised approach. As such, in this paper we outline how our proposal can be adapted to allow for the minimal possible integration of blockchain technology in a traditional Access Control system. In particular, we consider the scenario where Attribute Managers only may be managed on chain through smart contracts. We provide a proof of concept implementation based on Ethereum, and show its performance through experimental results

An analysis of the bitcoin users graph: Inferring unusual behaviours

An increasing interest on cryptocurrencies has recently raised, in particular on bitcoin. A unique feature of this system is that the list of all the economic transactions is publicly available. This makes available a large amount of information that can be analysed to discover the topological properties of the transaction graph and to obtain insights in the behaviour of the users. In a previous work we have presented a first set of analyses of the bitcoin network. Among other properties of the network, these analyses have also revealed a set of unusual patterns in the bitcoin users graph. We conjecture that these topological patterns are due to artificial users behaviors, not strictly related to normal economic interaction. In particular, in this paper, we analyse the outliers in the in-degree distribution of the bitcoin users graph. The results of our analysis support our conjecture, i.e. they are due to artificial transaction patterns

The graph structure of bitcoin

In this paper we study the structure of the Bitcoin users graph derived from the transactions data stored in the Bitcoin blockchain. This work analyzes the macroscopic structure of the connectivity components of such graph. As our graph represents an economic community, we give an economical interpretation of the different components. To do so we analyze the flow of value between the different components and study the entities contained in each of them. We also perform a temporal analysis of the components evolution to support our economical characterization

The bow tie structure of the Bitcoin users graph

The availability of the entire Bitcoin transaction history, stored in its public blockchain, offers interesting opportunities for analysing the transaction graph to obtain insight on users behaviour. This paper presents an analysis of the Bitcoin users graph, obtained by clustering the transaction graph, to highlight its connectivity structure and the economical meaning of the different obtained components. In fact, the bow tie structure, already observed for the graph of the web, is augmented, in the Bitocoin users graph, with the economical information about the entities involved. We study the connectivity components of the users graph individually, to infer their macroscopic contribution to the whole economy. We define and evaluate a set of measures of nodes inside each component to characterize and quantify such a contribution. We also perform a temporal analysis of the evolution of the resulting bow tie structure. Our findings confirm our hypothesis on the components semantic, defined in terms of their economical role in the flow of value inside the graph

Detecting artificial behaviours in the Bitcoin users graph

A unique feature of cryptocurrencies such as Bitcoin is that the blockchain containing all the economic transactions is publicly available. This makes it possible to obtain insights in the behaviour of the users through an analysis of the topological properties of the users graph which is derived from the Bitcoin transaction graph through clustering heuristics. In a previous work, we have analysed the users graph and discovered that the graph is not a small world, due to the presence of outliers in the in-degree frequency distribution of the nodes and of a high diameter, in spite of a small average distance between the nodes of the graph. In this paper, we explain our findings, showing that these structural properties of the network are due to peculiar unusual patterns in the users graph. As a further remark, we argue that these patterns are probably due to artificial users behaviours and not strictly related to normal economic interactions

Putting trust back in IP licensing: DLT smart licenses for the internet of things

Our proposal aims to help solving a trust problem between licensors and licensees that occurs during the active life of license agreements. We particularly focus on licensing of proprietary intellectual property (IP) that is embedded in Internet of Things (IoT) devices and services (e.g. patented technologies). To achieve this we propose to encode the logic of license agreements into smart licenses (SL). We define a SL as a 'digital twin' of a licensing contract, i.e. one or more smart contracts that represent the full or relevant parts of a licensing agreement in machine readable and executable code. As SL are self enforcing, the royalty computation and execution of payments can be fully automated in a tamper free and trustworthy way. This of course, requires to employ a Distributed Ledger Technology (DLT). Such an Automated Licensing Payment System (ALPS) can thus automate an established business process and solve a longstanding trust issue in licensing markets. It renders traditional costly audits obsolete, lowers entry barriers for those who want to participate in licensing markets, and enables novel business models too complex with traditional approaches