Each level is a superset of the previous level. For example, if a system is classified as class , then the system must follow the directives of class , and . If a system contains data or more than one sensitivity class, it must be classified according that needed for the most confidential data on the system. Data integrity is not vital. Loss of service due to malicious attacks is an acceptable danger.
Internal access is selective.
Data integrity is important but not vital. If such data were to be accessed by unauthorised persons, it could influence the company's operational effectiveness, cause an important financial loss, provide a significant gain to a competitor or cause a major drop in customer confidence. Data integrity is vital. Datacenters normally maintain this level of security. Salaries, Personnel data, Accounting data, passwords, information on corporate security weaknesses, very confidential customer data and confidential contracts.