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. Unauthorised external or internal access to this data would be critical to the company. Data integrity is vital. The number of people with access to this data should be very small.