The distributed nature of Internet of Things (IoT) and its rapid increase on a large scale raises many security and privacy issues. Access control is one of the major challenges currently addressed through centralized approaches that may rely on a third party and they are constrained by availability and scalability, which may result in a performance bottleneck. Therefore, this paper proposes a novel solution to manage the delivery of lightweight and decentralized secure access control of an IoT system based on a multi-agent system and a blockchain. The main objective of the proposed solution is to build Blockchain Managers (BCMs) for securing IoT access control, as well as allowing for secure communication between local IoT devices. Moreover, the solution also enables secure communication between IoT devices, fog nodes and cloud computing.

Coronavirus disease 2019 (COVID-19) is the name given by the World Health Organization (WHO) to the highly contagious and infectious disease caused by the Novel Corona Virus or SARS-CoV-2, which was first reported on 31 December 2019 in Wuhan city of the capital of China's Hubei province. Due to the rapid increase in the number of infections worldwide, the WHO in March 2020, declared COVID-19 as a pandemic. Historically, first coronavirus had surfaced in 1965 with symptoms of common cold. Since then five different strands of this virus have emerged, most lethal of them was the Severe Acute Respiratory Syndrome (SARS), which infected about eight thousand people, killing ten percent of them. The COVID-19 is not the most deadly pandemic world has ever witnessed as the Spanish influenza pandemic, during 1918–19, killed more than fifty million people. Indeed COVID-19 has turned out to be the most lethal of all coronaviruses as it has infected at least three million people killing more than two hundred thousands of them in the first 4 months of its spread. Many politicians and social scientists have dubbed the depression, being caused by COVID-19, worse than that caused by the Second World War. In this article, we shall analyze economic, social, cultural, educational and political impact of the COVID-19.

Location Based Services (LBS) expose user data to malicious attacks. Approaches, evolved, so far, for preserving privacy and security, suffer from one or more anomalies, and hence the problem of securing LBS data is far from being resolved. In particular, accuracy of results vs. privacy degree, privacy vs. performance, and trust between users are open problems. In this article, we present a novel approach by integration of peer-to-peer (P2P) with the caching technique and dummies from real queries. Our approach increases efficiency, leads to improved performance, and provides solutions to many problems that have existed in the past. In addition, we offer an improved way of managing cache. Simulation demonstrates superiority of our approach over earlier ones dealing with both the ratio of privacy and that of performance.

Thousands of people have lost their lives in stampedes and other crowd related disasters in recent years. Most of these fatalities seem to have been caused by poor control and management of crowds, which is discussed in this article. An efficient and effective crowd management system must also have a plan to deal with the ongoing threat of terrorism and outbreak of various kinds of communicable diseases. In this article, we present a framework of a Crowd Control and Health Management System specially designed to prevent and manage stampedes and other disasters. The system has two subsystems; one for dealing with the management of stampedes and other disasters and the other with healthcare management. As part of the proposed system, an algorithm for an early detection of stampedes, with proof and simulation of implementation, is provided. As part of the healthcare management subsystem, we integrate several mobile applications and develop four of them dealing with relief issues, blood donations, complaints and alerts, and utilizing mobile phones as a sensor device. Our system makes use of various kinds of wireless, mobile, and other technologies and tools including Fog Computing, Smart Phones, Smart Digital Street, IP‐Cameras, Radio Frequency Identification (RFID), Voice Alarm, Light Alarm, and Global Positioning System (GPS). We compare merits and effectiveness of RFID and Wireless Sensor Networks (WSNs), as well as those of Cloud and Fog with a view of using them as part of the proposed framework. We also discuss applications of our systems in real‐life cases of Hajj, an annual pilgrimage of millions of people to Mecca, and Kumbh Mela, a periodic gathering of tens of millions of people in India, both of which have accounted for the majority of fatalities in stampedes and other disasters.