Passwords can be used to control access to terminals, files, records, or even fields within a record. In a password system, users must enter the appropriate password to gain access to the data for which they have been cleared. Multiple levels of passwords can provide entry to different layers of information in an agency data base. The best approach is to use passwords to create a hierarchy of entry and progressively more complex entry codes as the information becomes more sensitive. Callback devises prevent unauthorized access to the communications channels of a computer.
Some devices require a caller to provide an identification number and hang up.
After verifying the user's access rights, the device calls the user back. Security software programs can audit computer use by providing a comprehensive record of all network or system activity, including who is accessing what data, when, and how often. When the encrypted data are sent to another terminal, the required software key on the receiving end decodes the information. The use of encryption can be a complex process and should be used only for data that are highly confidential and require utmost security. Data Backups .