The series of DIGILIENCE conferences, the first of which took place in Sofia, 2-4 October 2019, and the second one in Varna, 30 Sep – 2 Oct 2020, aims to establish the state of the art and future demands in the provision of security and resilience of processes, services, and systems that are heavily reliant on information technologies.

The third International Scientific Conference “Digital Transformation, Cyber Security and Resilience” (DIGILIENCE 2021) took place in Veliko Tarnovo, Bulgaria, within the period September 29 – October 1, 2021, at the National Military University “Vasil Levski”.

The rapid development and massive incorporation of advanced technologies transform industries, services, conflict, government, healthcare, leisure, and social interaction. In the strive for competitive positioning, developers and users often underestimate safety and security considerations, which in turn provides ample opportunities for exploitation by malicious actors. With these aims in mind, the Steering Committee received original contributions to addressing the following core topics:

• Cyber Security Situational Awareness
• AI for Cyber and Cyber for AI
• Operations in Cyberspace
• ICT Governance for Effectiveness, Efficiency, and Resilience
• The Human Factor in Cyber Security and Resilience
• Education and Training, Development of Critical Digital Competencies for Transformation
• Cyber Resilience of Industry 4.0
• Protecting Critical Infrastructures from Cyberattacks
• Cybersecurity of Biophysical and Biomedical Systems
• Societal Resilience to Cybrid Influence
• Digital Organizations in a Big Data Environment
• Sharing Data in Support of Digital Transformation