A security clearance is an authorization that allows access to information that would otherwise be forbidden. Security clearances are commonly used in industry and government. Many jobs in information technology require security clearances. When a security clearance is required for access to specific information, the information is said to be classified. Security clearances can be issued for individuals or for groups.
In some organizations, corporations, and agencies, there are multiple levels of security clearance. The terms used for the classifications, and the requirements imposed on applicants, vary among countries and entities. In the United States, the two most common government security clearances are known as Secret and Top Secret. In order to obtain a security clearance, a person must meet certain requirements concerning character, criminal record, and credit history. The higher the level of the security clearance, the more strict are the requirements.