Security is the degree of resistance to, or protection from, harm. It applies to any vulnerable and/or valuable asset, such as a person, dwelling, community, item, nation, or organization. Security is said to have two dialogues. Negative dialogue is about danger, risk, threat, etc. Positive dialogue is about opportunities, interests, profits, etc. Negative dialogue needs military equipment, armies, or police. Positive dialogue needs social capital, education, or social interaction.

Security theater is a critical term for deployment of measures primarily aimed at raising subjective security without a genuine or commensurate concern for the effects of that action on real safety. For example, some consider the screening of airline passengers based on static databases to have been Security theater and the Computer Assisted Passenger Prescreening System to have created a decrease in objective security.