A Framework to Evaluate Blockchain Interoperability Solutions

<div><div><br></div><div>Decentralized ledger technology (DLT), in particular blockchain, is becoming ubiquitous in today's society. Just in the second quarter of 2021, centralized and decentralized exchanges had a volume of around $600 billion. Enterprises are adopting this technology, following the opportunity to expand to new businesses. However, they need to connect their existing systems and processes to blockchains securely and reliably. Blockchain interoperability (BI) is emerging as one of the crucial features of blockchain technology. Fueled by the need to eliminate data and value silos, they realize the necessary bridge between centralized and decentralized systems.</div><div>As BI is still maturing, there are many unsolved challenges. In particular, it is still difficult for developers and practitioners to have control over processes spawning across several DLTs.</div><div>In this report, we focus on the problem of managing cross-chain state in an integrated manner. First, we introduce the concept of cross-chain logic/cross-chain rules. After that, we present and discuss the results of our BI survey. Finally, we propose the BI evaluation framework, the first step to systematically evaluate BI solutions.</div></div>

A Framework to Evaluate Blockchain Interoperability Solutions

<div><div><br></div><div>Decentralized ledger technology (DLT), in particular blockchain, is becoming ubiquitous in today's society. Just in the second quarter of 2021, centralized and decentralized exchanges had a volume of around $600 billion. Enterprises are adopting this technology, following the opportunity to expand to new businesses. However, they need to connect their existing systems and processes to blockchains securely and reliably. Blockchain interoperability (BI) is emerging as one of the crucial features of blockchain technology. Fueled by the need to eliminate data and value silos, they realize the necessary bridge between centralized and decentralized systems.</div><div>As BI is still maturing, there are many unsolved challenges. In particular, it is still difficult for developers and practitioners to have control over processes spawning across several DLTs.</div><div>In this report, we focus on the problem of managing cross-chain state in an integrated manner. First, we introduce the concept of cross-chain logic/cross-chain rules. After that, we present and discuss the results of our BI survey. Finally, we propose the BI evaluation framework, the first step to systematically evaluate BI solutions.</div></div>

A Framework to Evaluate Blockchain Interoperability Solutions

<div><div><br></div><div>Decentralized ledger technology (DLT), in particular blockchain, is becoming ubiquitous in today's society. Just in the second quarter of 2021, centralized and decentralized exchanges had a volume of around $600 billion. Enterprises are adopting this technology, following the opportunity to expand to new businesses. However, they need to connect their existing systems and processes to blockchains securely and reliably. Blockchain interoperability (BI) is emerging as one of the crucial features of blockchain technology. Fueled by the need to eliminate data and value silos, they realize the necessary bridge between centralized and decentralized systems.</div><div>As BI is still maturing, there are many unsolved challenges. In particular, it is still difficult for developers and practitioners to have control over processes spawning across several DLTs.</div><div>In this report, we focus on the problem of managing cross-chain state in an integrated manner. First, we introduce the concept of cross-chain logic/cross-chain rules. After that, we present and discuss the results of our BI survey. Finally, we propose the BI evaluation framework, the first step to systematically evaluate BI solutions.</div></div>

FACTORS AFFECTING CAPITAL EXPENDITURES AND COMMUNITY WELFARE IN KALIMANTAN

From centralized to decentralized systems provides new hope for most provinces in Indonesia. With government decentralization, it means that management authority will be distributed from the center to the regions. This study aims to examine and prove whether Locally-Generated Revenue (Pendapatan Asli Daerah–PAD), Special Allocation Fund (Dana Alokasi Khusus-DAK), General Allocation Fund (Dana Alokasi Umum-DAU), Profit-Sharing Fund (Distribusi Bagi Hasil–DBH) affect capital expenditure and community welfare in Kalimantan. The population in this study are districts and cities in Kalimantan, consisting of 47 districts and 9 cities. The method used to determine the sample is purposive sampling, which selects samples with certain criteria. From a population of 56, this study examines a sample of 49 observations (42 districts and 7 cities). The results show that PAD, DAK, DAU, and DBH positively impact capital expenditure in Kalimantan. However, capital expenditure has no effect on community welfare in Kalimantan.

Designated-Verifier Anonymous Credential for Identity Management in Decentralized Systems

Most of the existing identity management is the centralized architecture that has to validate, certify, and manage identity in a centralized approach by trusted authorities. Decentralized identity is causing widespread public concern because it enables to give back control of identity to clients, and the client then has the ability to control when, where, and with whom they share their credentials. A decentralized solution atop on blockchain will bypass the centralized architecture and address the single point of the failure problem. To our knowledge, blockchain is an inherited pseudonym but it cannot achieve anonymity and auditability directly. In this paper, we approach the problem of decentralized identity management starting from the designated-verifier anonymous credential (DVAC in short). DVAC would assist to build a new practical decentralized identity management with anonymity and auditability. Apart from the advantages of the conventional anonymous credential, the main advantage of the proposed DVAC atop blockchain is that the issued cryptographic token will be divided into shares at the issue phase and will be combined at the showing credential phase. Further, the smooth projective hash function ( SPHF in short) is regarded as a designated-verifier zero-knowledge proof system. Thus, we introduce the SPHF to achieve the designated verifiability without compromising the privacy of clients. Finally, the security of the proposed DVAC is proved along with theoretical and experimental evaluations.

DESIRE: Leveraging the best of centralized and decentralized contact tracing systems

Contact tracing in case of pandemic is becoming an essential mitigation tool for national health services to break infection chains and preventing the virus from spreading further. To support manual tracing, several countries have been developing contact tracing apps that detect nearby mobile phones using Bluetooth. Such data collection raised privacy concerns and several privacy-preserving protocols have been proposed to prevent the leakage of personal and sensitive information. These solutions are mainly divided into two categories using a centralized or a decentralized exposure score computation. However, both approaches depict limitations. This paper presents Desire, a novel exposure notification system which leverages the best of centralized and decentralized systems. As opposed to existing contact tracing schemes, desire leverages Private Encounter Tokens (PETs) generated locally on the device that uniquely identify an encounter between two nodes while being private and unlinkable by the server. The role of the server is merely to match PETs generated by diagnosed users with the pets provided by requesting users. Our privacy risk analysis shows that Desire drastically improves privacy against malicious users (i.e., limitation of decentralized systems) and authority (i.e., limitation of centralised systems). We implemented Desire and evaluated it in real condition.

Different approaches to selection of surgical trainees in the European Union

Background There is an increasing global interest in selection processes for candidates to surgical training. The aim of the present study is to compare selection processes to specialist surgeon training in the European Union (EU). A secondary goal is to provide guidance for evidence-based methods by a proposed minimum standard that would align countries within the EU. Methods Publications and grey literature describing selection strategies were sought. Correspondence with Union Européenne des Médecins Specialists (UEMS) Section of Surgery delegates was undertaken to solicit current information on national selection processes. Content analysis of 13 semi-structured interviews with experienced Swedish surgeons on the selection process. Two field trips to Ireland, a country with a centralized selection process were conducted. Based on collated information typical cases of selection in a centralized and decentralized setting, Ireland and Sweden, are described and compared. Results A multitude of methods for selection to surgical training programs were documented in the 27 investigated countries, ranging from locally run processes with unstructured interviews to national systems for selection of trainees with elaborate structured interviews, and non-technical and technical skills assessments. Associated with the difference between centralized and decentralized selection systems is whether surgical training is primarily governed by an employment or educational logic. Ireland had the most centralized and elaborate system, conducting a double selection process using evidence-based methods along an educational logic. On the opposite end of the scale Sweden has a decentralized, local selection process with a paucity of evidence-based methods, no national guidelines and operates along an employment logic, and Spain that rely solely on examination tests to rank candidates. Conclusion The studied European countries all have different processes for selection of surgical trainees and the use of evidence-based methods for selection is variable despite similar educational systems. Selection in decentralized systems is currently often conducted non-transparent and subjectively. A suggested improvement towards an evidence-based framework for selection applicable in centralized and decentralized systems as well as educational and employer logics is suggested.