The book explores the transformation of national security policies in the context of a rapidly evolving digital environment, with a comparative focus on Romania and Bulgaria. Anchored in political science, the research examines how these two NATO and EU member states adapt their cybersecurity governance to increasing threats, including state-sponsored attacks, organized cybercrime, hybrid warfare, and disinformation campaigns. Covering the period 2018-2025, the study employs qualitative and comparative methodologies to assess institutional resilience, legal frameworks, and public policy responses. Findings reveal critical asymmetries, legislative gaps, and limited cross-sector coordination. The dissertation also integrates a geopolitical dimension, linking digital threats with regional instability-especially the war in Ukraine-and strategic vulnerabilities along NATO's eastern flank. It emphasizes the need for democratic accountability in cybersecurity policymaking and proposes adaptive strategies for national and regional cooperation. By conceptualizing cybersecurity as a central pillar of national security, the research offers theoretical and practical contributions that enrich political science and inform public policy design in digitally exposed democracies.