A computer network is disclosed comprising a plurality of interconnected network devices including a plurality of client computers, an authentication server computer operated by a system administrator, and a disk drive connected to the authentication server computer. The disk drive comprises an interface for receiving the personal authentication data and user access data from the system administrator, a disk for storing data, and a disk controller for controlling access to the disk. An authenticator within the disk drive, responsive to the personal authentication data, enables the disk controller, and cryptographic circuitry encrypts the user access data received from the system administrator into encrypted data stored on the disk.