Security

Security is freedom from, or resilience against, potential harm (or other unwanted coercive change) caused by others. Beneficiaries (technically referents) of security may be of persons and social groups, objects and institutions, ecosystems or any other entity or phenomenon vulnerable to unwanted change. 
Security mostly refers to protection from hostile forces, but it has a wide range of other senses: for example, as the absence of harm (e.g. freedom from want); as the presence of an essential good (e.g. food security); as resilience against potential damage or harm (e.g. secure foundations); as secrecy (e.g. a secure telephone line); as containment (e.g. a secure room or cell); and as a state of mind (e.g. emotional security).
The term is also used to refer to acts and systems whose purpose may be to provide security (e.g.: security companies, security forces, security guard, cyber security systems, security cameras, remote guarding).
Security is not only physical but it can also be Virtual.
Etymology.
The word 'secure' entered the English language in the 16th century. It is derived from Latin "securus", meaning freedom from anxiety: "se" (without) + "cura" (care, anxiety).
Overview.
Referent.
A security referent is the focus of a security policy or discourse; for example, a referent may be a potential beneficiary (or victim) of a security policy or system.
Security referents may be persons or social groups, objects, institutions, ecosystems, or any other phenomenon vulnerable to unwanted change by the forces of its environment. The referent in question may combine many referents, in the same way that, for example, a nation state is composed of many individual citizens.
Context.
The security context is the relationships between a security referent and its environment. From this perspective, security and insecurity depend first on whether the environment is beneficial or hostile to the referent, and also how capable is the referent of responding to its/their environment in order to survive and thrive.
Capabilities.
The means by which a referent provides for security (or is provided for) vary widely. They include, for example:
Effects.
Any action intended to provide security may have multiple effects. For example, an action may have wide benefit, enhancing security for several or all security referents in the context; alternatively, the action may be effective only temporarily, or benefit one referent at the expense of another, or be entirely ineffective or counterproductive.
Contested approaches.
Approaches to security are contested and the subject of debate. For example, in debate about national security strategies, some argue that security depends principally on developing protective and coercive capabilities in order to protect the security referent in a hostile environment (and potentially to project that power into its environment, and dominate it to the point of strategic supremacy). Others argue that security depends principally on building the conditions in which equitable relationships can develop, partly by reducing antagonism between actors, ensuring that fundamental needs can be met, and also that differences of interest can be negotiated effectively.
Contexts of security (examples).
The table shows some of the main domains where security concerns are prominent.
IT realm
Political
Monetary
The range of security contexts is illustrated by the following examples (in alphabetical order):
Computer security.
Computer security, also known as cybersecurity or IT security, refers to the security of computing devices such as computers and smartphones, as well as computer networks such as private and public networks, and the Internet. The field has growing importance due to the increasing reliance on computer systems in most societies. It concerns the protection of hardware, software, data, people, and also the procedures by which systems are accessed. The means of computer security include the physical security of systems and security of information held on them.
Corporate security.
Corporate security refers to the resilience of corporations against espionage, theft, damage, and other threats. The security of corporations has become more complex as reliance on IT systems has increased, and their physical presence has become more highly distributed across several countries, including environments that are, or may rapidly become, hostile to them.
Ecological security.
Ecological security, also known as environmental security, refers to the integrity of ecosystems and the biosphere, particularly in relation to their capacity to sustain a diversity of life-forms (including human life). The security of ecosystems has attracted greater attention as the impact of ecological damage by humans has grown.
Food security.
Food security refers to the ready supply of, and access to, safe and nutritious food. Food security is gaining in importance as the world's population has grown and productive land has diminished through overuse and climate change.
Home security.
Home security normally refers to the security systems used on a property used as a dwelling (commonly including doors, locks, alarm systems, lighting, fencing); and personal security practices (such as ensuring doors are locked, alarms activated, windows closed etc.)
Human security.
Human security is the name of an emerging paradigm which, in response to traditional emphasis on the right of nation states to protect themselves, has focused on the primacy of the security of people (individuals and communities). The concept is supported by the United Nations General Assembly, which has stressed "the right of people to live in freedom and dignity" and recognized "that all individuals, in particular vulnerable people, are entitled to freedom from fear and freedom from want".
National security.
National security refers to the security of a nation state, including its people, economy, and institutions. In practice, state governments rely on a wide range of means, including diplomacy, economic power, and military capabilities.
Perceptions of security.
Since it is not possible to know with precision the extent to which something is 'secure' (and a measure of vulnerability is unavoidable), perceptions of security vary, often greatly. For example, a fear of death by earthquake is common in the United States (US), but slipping on the bathroom floor kills more people; and in France, the United Kingdom and the US there are far fewer deaths caused by terrorism than there are women killed by their partners in the home.
Another problem of perception is the common assumption that the mere presence of a security system (such as armed forces, or antivirus software) implies security. For example, two computer security programs installed on the same device can prevent each other from working properly, while the user assumes that he or she benefits from twice the protection that only one program would afford.
Security theater is a critical term for measures that change perceptions of security without necessarily affecting security itself. For example, visual signs of security protections, such as a home that advertises its alarm system, may deter an intruder, whether or not the system functions properly. Similarly, the increased presence of military personnel on the streets of a city after a terrorist attack may help to reassure the public, whether or not it diminishes the risk of further attacks.
Security concepts (examples).
Certain concepts recur throughout different fields of security: