In a technological landscape marked by the accelerated expansion of the Internet of Things (IoT), securing edge communications is becoming essential for ensuring trust, confidentiality and data integrity. The constant evolution of cyber attacks, combined with the resource limitations of IoT devices, requires the development of effective, adaptable and scalable security solutions. This paper provides a comprehensive review of recent advances and persistent challenges in securing edge communications in the IoT, with a focus on lightweight cryptographic algorithms (ASCON, PRESENT, SIMON, SPECK) and on authentication mechanisms adapted to resource-constrained devices. The trade-offs between performance and security are emphasized, besides the need for IoT-specific Anonymous Overlay Networks(AONs) and Anonymous Routing Protocols(ARPs) capable of providing protection against traffic analysis and user anonymity. The study includes a detailed classification of 18 ARPs protocols, along with a presentation of the metrics used in evaluation. It also exposes MQTT-SN protocol vulnerabilities and proposes the development of standardized security frameworks with built-in encryption and authentication for scalable IoT deployments. The main finding of the study highlights the need for further research in developing tailored security solutions for IoT devices, as well as enhancing the security of the MQTT-SN protocol.

In an era of connectivity, the Internet of Things introduces smart solutions for smart and sustainable agriculture, bringing alternatives to overcome the food crisis. Among these solutions, smart greenhouses support crop and vegetable agriculture regardless of season and cultivated area by carefully controlling and managing parameters like temperature, air and soil humidity, and light. Smart technologies have proven to be successful tools for increasing agricultural production at both the macro and micro levels, which is an important step in streamlining small-scale agriculture. This paper presents an experimental Internet of Things-based small-scale greenhouse prototype as a proof of concept for the benefits of merging smart sensing, connectivity, IoT, and mobile-based applications, for growing cultures. Our proposed solution is cost-friendly and includes a photovoltaic panel and a buffer battery for reducing energy consumption costs, while also assuring functionality during night and cloudy weather and a mobile application for easy data visualization and monitoring of the greenhouse.

Wireless Sensor Networks gradually became a mature technology that enabled the implementation of a large number of critical applications. However, the integration of such networks in much more complex systems, such as IoT, still poses a major challenge. In this paper we present a viable solution to accomplish such a difficult task by using MQTT-SN to integrate critical real-time WSNs into an IoT platform. The core of our work is a platform independent real-time driver for MQTT-SN along with a communication architecture to enable the integration of low end devices into an MQTT network using MQTT-SN. We also describe a comprehensive practical demonstration using real hardware modules that validates our claimed solution.

The security of Internet of Things (IoT) systems has consistently been a challenge, particularly in the context of critical infrastructure. One particular approach not yet employed in this domain is the unidirectional communication paradigm. This survey presents an analysis of the most prevalent unidirectional communication solutions, namely, data diodes, network pumps, unidirectional gateways, and unidirectional protocols. The objective of the survey is to present an analysis of the unidirectional communication methods that meet the requirements of IoT security. These methods are classified according to their implementation and operational mode. The survey analyzes the unidirectional communication solutions based on their performance, the level of security offered, the cost-effectiveness, and their cost of implementation. Additionally, it includes an analysis of the existing off-the-shelf unidirectional communication implementations found in the industry. Furthermore, it identifies some of the most important current issues and development directions.

Sensor networks become increasingly a key technology for complex control applications. Their potential use in safety- and time-critical domains has raised the need for task scheduling mechanisms specially adapted to sensor node specific requirements, often materialized in predictable jitter-less execution of tasks characterized by different criticality levels. This paper offers an efficient scheduling solution, named Hybrid Hard Real-Time Scheduling (H²RTS), which combines a static, clock driven method with a dynamic, event driven scheduling technique, in order to provide high execution predictability, while keeping a high node Central Processing Unit (CPU) utilization factor. From the detailed, integrated schedulability analysis of the H²RTS, a set of sufficiency tests are introduced and demonstrated based on the processor demand and linear upper bound metrics. The performance and correct behavior of the proposed hybrid scheduling technique have been extensively evaluated and validated both on a simulator and on a sensor mote equipped with ARM7 microcontroller.

The real-time characteristics of modular systems have been a long sought-after goal in many industries including automotive, aeronautics or mobile robotics. Yet scientists and practitioners are still struggling to find widespread implementation solutions that may accommodate diverse inter-modular real-time communication requirements. In an attempt to cover this research gap, the current paper proposes a real-time version of the PARSECS protocol for low-end devices. Our new protocol, coined as PARSECS_RT, was designed according to Open Systems Interconnection Reference Model. It offers a full communication stack from the physical layer to the application layer on top of the SPI interface in order to provide a stable, hard real-time communication platform. PARSECS_RT was evaluated in real and simulated environments providing promising results.