Blockchain Trilemma Solver Algorand has Dilemma over Undecidable Messages

Recently, an ingenious protocol called Algorand has been proposed to overcome these limitations. Algorand uses an innovative process - called cryptographic sortition - to securely and unpredictably elect a set of voters from the network periodically. These voters are responsible for reaching consensus through a Byzantine Agreement (BA) protocol on one block per time, guaranteeing an overwhelming probability of linearity of the blockchain. In this paper, we present a security analysis of Algorand. To the best of our knowledge, it is the first security analysis as well as the first formal study on Algorand. We designed an attack scenario in which a group of malicious users tries to break the protocol, or at least limiting it to a reduced partition of network users, by exploiting a possible security flaw in the messages validation process of the BA. Since the source code or an official simulator for Algorand was not available at the time of our study, we created a simulator (which is available on request) to implement the protocol and assess the feasibility of our attack scenario. Our attack requires the attacker to have a trivial capability of establishing multiple connections with targeted nodes and costs practically nothing to the attacker. Our results show that it is possible to slow down the message validation process on honest nodes, which eventually forces them to choose default values on the consensus; leaving the targeted nodes behind in the chain as compared to the non-attacked nodes. Even though our results are subject to the real implementation assumption, the core concept of our attack remains valid.Comment: 8 pages, 2 figures, and 2 table

A Model For Improving Ethics In Construction Materials And Products Supply Chain Using Blockchain

There are countless materials and products that make up a building, including cladding, glazing, roofing, floors, ceilings, systems, etc., and the hidden and fragmented structure of the supply chain makes it highly vulnerable to several forms of ethical breaches at different tiers. Consumers also are increasingly concerned about where the products they are buying come from, highlighting important areas of concern that include the ethical, environmental, and social issues. Whereas current research identifies digitalization as a key part of providing transparency and increasing fairness in supply chains, and blockchain technology is lauded as having the potential to deliver this. However, while there has been a growing emphasis on ethics in construction in recent years, and an increase in studies around blockchain, there remains a paucity of studies related to how blockchain may help to improve the environmental and social dimensions of ethics in construction supply chains. A gap that this study fills through a holistic triple bottom line (TBL) approach. To achieve this, the study aims to develop and validate a model for improving ethics in construction materials and products supply chains (CMPSC) following the TBL construct using blockchain technology. The study also explores the current state of ethics in the CMPSC and the implementations of blockchain for ethics and applies the learnings to develop a conceptual model to improve environmental, social and business ethics in the CMPSC using blockchain. The model was then refined and validated via a dual-phase validation protocol consisting of expert interviews and focus group discussions. A total of 30 participants participated in this study, this comprised of 16 construction industry supply chain professionals, 10 professionals in the ethics/ sustainability in construction and 4 blockchain technology experts. NVivo 12 was utilised to thematically analyse both the interviews and the focus group data. This approach was utilised to investigate the data from both a data-driven perspective (a perspective based on coding in an inductive way); and from the research question perspective (to check if the data is consistent with the research questions and if it provides sufficient information). The 30 interviews resulted in 4 high-level themes, 15 mid-level themes and 28 low-level themes, with the total number of codes within the themes being 721. The analysis of the focus group data resulted in 3 high-level themes and 10 mid-level themes, bringing the total number of codes within all themes to 74. Results from this study revealed that the effectiveness of current ethical measures in the CMPSC has been limited due to weak implementation and compliance, the inability of the government to play its role, and the outright denial of unethical practises within supply chains. Results also show that even though greater emphasis is placed on the business component of ethics while the environmental or social component may only receive as much attention if it can be monetised or if it is demanded; nonetheless, the current state of ethics in the CMPSC remains weak across the three dimensions examined. Further results show that while blockchain may help improve ethics in the CMPSC, in addition to the transparency and digitization that technology provides, the need for education and the upholding of personal ethical values by supply chain players are key to the success of both current and new ethical supply chain initiatives. Individuals must first be made ethically aware in order to act ethically; only then may the implementation of a technological tool prosper. The main contribution of this study to knowledge is the development of a model for improving ethics in the CMPSC within the TBL construct through blockchain technology. The model developed in this study provides practical clarity on how blockchain may be implemented within fragmented supply chains and a significant understanding of a socio-technical approach to addressing the issue of ethics within construction supply chains. It also has a vital role in helping the intended users and actors improve their knowledge of the technology and how blockchain can help to improve ethics in the CMPSC and also understand their roles and responsibilities on the network, thereby providing a framework and prerequisite guidance for the Blockchain-as-a-Service (BaaS) providers in the development of the computer model (blockchain network). The findings of this thesis demonstrate new insights and contribute to the existing body of knowledge by further advancing the discussion on the role of the blockchain in the construction industry