Highly sensitive data should NOT be kept resident on a hard disk . The only way to effectively secure such data on a hard disk is to encrypt it. However, encryption is suitable only for small files such as spreadsheets, or word processing documents which must reside on a hard disk. Data Encryption is not an ideal solution to security problems. Even the vendor of the encryption software cannot help if the key is lost.
Encryption is slow.
It may take as long as a minute to encrypt or decrypt a 50K file. Microcomputers processing sensitive data should never be left unattended. This includes recalculating spreadsheets, printing reports, or processing a data base. This prevents unauthorized individuals from stopping the application processing, reading or changing the information, and restarting the application without detection. After processing a sensitive application, the microcomputer should also be rebooted, or turned off for at least one minute.