Special Issue, Signals Journal Critical Infrastructures are defined as 'assets, systems or part thereof which are essential for the maintenance of vital societal functions, health, safety, security, economic or social well-being of people, and the disruption or destruction of which would have a significant impact as a result of the failure to maintain those functions.' Critical Infrastructures refer to a multitude of sectors, including energy, manufacturing, transportation, healthcare and public safety. Systems deployed within these sectors integrate both information technologies and operational technologies, being commonly reliant on legacy industrial control and cyber-physical systems. Nevertheless, novel disruptive and enabling information and communication technologies are increasingly integrated, increasing connectivity and interdependencies, thus presenting security professionals with significant challenges in maintaining and enhancing the security and resilience of such infrastructures. This Special Issue invites submissions that present innovative ideas, proof of concepts, use cases, and results from a variety of topics relevant to critical infrastructure cybersecurity and resilience, including (but not limited to) the following ones: Security Governance * Security policies * Risk analysis and management * Vulnerability assessment and metrics * Awareness, training, and simulation * ICS/CPS security standards * Privacy and Anonymity in ICS/CPS System and Network Security * Threat modelling * Security architectures * Access control * Malware and cyber weapons * Intrusion detection and visualization * Defence in depth * Monitoring and real-time supervision * Applied cryptography * Perimeter security * Safety-security interactions * Cybersecurity engineering * Secure communication protocols * Formal models for ICS/CPS security * Hardware Security * Resilient ICS/CPS * Application Security * Secure Firmware Incident Response and Digital Forensics for ICS/CPS * Forensics in ICS * Incident Response * Accountability Case Studies * Case studies in the energy, utility, chemical, transportation, manufacturing, and other industrial and critical infrastructure sectors Please note that all of the submitted papers must be within the general scope of the Signals journal. Furthermore, we can currently invite contributions to the special issue with a discount on publication fees. If you are working on something relevant to the topics above, feel free to reach out to us. Link: https://www.mdpi.com/journal/signals/special_issues/Critical_Infrastructures_Cybersecurity_Resilience Deadline for manuscript submissions: 15 June 2021. Guest Editors Dr. Vasileios Gkioulos Dr. Marios Anagnostopoulos Dr. Sandeep Pirbhulal Dr. Georgios Spathoulas Dr. Ajay Nehra NB: requires article processing charge.