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.

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.