Editorial: Security and Privacy Protection for Mobile Applications and Platforms.

The selected papers focus on different topics covered under the umbrella of Smart City concept such as: Lightweight security mechanisms for IoT; Blockchain-based IoT security; Physical-layer security; Security and privacy for mobile devices; Cybersecurity for Cyber Physical Production Systems (CPPSs); among others. In the third article with the title "A Physical-Layer Key Distribution Mechanism for IoT Networks", the authors focus on constrained IoT networks and propose physical layer security as a lightweight approach for key distribution mechanisms. Although physical layer security has been widely studied as a lightweight approach to transmit confidential information, authors in this article propose physical layer security for symmetric key agreement between multiple entities. [Extracted from the article]