A data communication system providing for the secure transfer and sharing of data via a local area network and/or a wide area network. The system includes a secure processing unit which communicates with a personal keying device and a crypto media controller attached to a user's Workstation. The communication between these processing elements generates a variety of data elements including keys, identifiers, and attributes. The data elements are used to identify and authenticate the user, assign user security access rights and privileges, and assign media and device attributes to a data access device according to a predefined security policy. The data elements are manipulated, combined, protected, and distributed through the network to the appropriate data access devices, which prevents the user from obtaining unauthorized data.