Security in traditional public law literature is often viewed as an objective and measurable state, characterized by indicators such as crime rates or defense capabilities. However, the emergence of "Cognitive Warfare" demonstrates that the "feeling of security" or perceptual security is an independent and fundamental matter, not merely a reflection of external reality. The central question of this research is whether the state bears legal responsibility for citizens' perception of security, or if its responsibility is strictly limited to providing objective security. Using a descriptive-analytical method and relying on library documents, statutory laws, and jurisprudential foundations, this research argues that perceptual security is not merely a psychological state but a "relational public good." Its realization depends on the quality of institutions, informational transparency, and the predictability of public administration. The findings indicate that the state's responsibility for perceptual security transcends moral obligation and elevates to a "positive legal obligation." However, Iran's legal system faces serious challenges in fulfilling this responsibility, such as legislative gaps regarding Deepfakes and AI-generated fake news. There is also a conflict between security surveillance requirements and privacy (Article 25 of the Constitution). Accordingly, transitioning from a reactive to a preventive approach requires drafting a comprehensive cognitive defense law, establishing coordinating institutions, and redefining the scope of the state's international responsibility.