This article is on broadcast and agreement in asynchronous message-passing systems made up of n processes, and where up to t processes may have a Byzantine Behavior. Its first contribution is a powerful, yet simple, all-to-all broadcast communication abstraction suited to binary values. This abstraction, which copes with up to t < n /3 Byzantine processes, allows each process to broadcast a binary value, and obtain a set of values such that (1) no value broadcast only by Byzantine processes can belong to the set of a correct process, and (2) if the set obtained by a correct process contains a single value v , then the set obtained by any correct process contains v . The second contribution of this article is a new round-based asynchronous consensus algorithm that copes with up to t < n /3 Byzantine processes. This algorithm is based on the previous binary broadcast abstraction and a weak common coin. In addition to being signature-free and optimal with respect to the value of t , this consensus algorithm has several noteworthy properties: the expected number of rounds to decide is constant; each round is composed of a constant number of communication steps and involves O ( n 2) messages; each message is composed of a round number plus a constant number of bits. Moreover, the algorithm tolerates message reordering by the adversary (i.e., the Byzantine processes).

Nowadays, the coronavirus pandemic has and is still causing large numbers of deaths and infected people. Although governments all over the world have taken severe measurements to slow down the virus spreading (e.g., travel restrictions, suspending all sportive, social, and economic activities, quarantines, social distancing, etc.), a lot of persons have died and a lot more are still in danger. Indeed, a recently conducted study [1] has reported that 79% of the confirmed infections in China were caused by undocumented patients who had no symptoms. In the same context, in numerous other countries, since coronavirus takes several days before the emergence of symptoms, it has also been reported that the known number of infections is not representative of the real number of infected people (the actual number is expected to be much higher). That is to say, asymptomatic patients are the main factor behind the large quick spreading of coronavirus and are also the major reason that caused governments to lose control over this critical situation. To contribute to remedying this global pandemic, in this paper, we propose an IoTa investigation system that was specifically designed to spot both undocumented patients and infectious places. The goal is to help the authorities to disinfect high-contamination sites and confine persons even if they have no apparent symptoms. The proposed system also allows determining all persons who had close contact with infected or suspected patients. Consequently, rapid isolation of suspicious cases and more efficient control over any pandemic propagation can be achieved. aIoT: Internet of Things.

Since its inception, Blockchain Technology, the underlying technology of Bitcoin has gained a lot of popularity and interest in various industries, varying from the healthcare industry, Internet-of-Things, smart grid, and supply chain management. Sports is one industry where blockchain can have significant breakthroughs where it can reshape the way the sports industry works by providing reliable athlete data management, secure mechanisms for data sharing, reforming the event management practices, collectibles traceability, and many more, but so far its impact is overshadowed by the hype surrounding the use of fan tokens and Non-Fungible-Tokens (NFT) collectibles. This paper aims to provide a systematic review of the ongoing research on the application of blockchain in the sports industry. this work shows that many studies have proposed different use cases for the application of blockchain in the sports industry on and off the field and targeting different stakeholders. However, we inferred a lack of adequate prototype implementations to evaluate the effectiveness of these proposed use cases. We further highlighted the technical details of the implementation of these blockchain-based applications, their limitations, and challenges, and proposed some solutions to support the integration of blockchain in this domain. The findings of this work will be beneficial for researchers, policymakers, and practitioners in the sports industry.