BUS BRIDGE SECURITY SYSTEM AND METHOD FOR COMPUTERS

摘要

A computer security system comprising security logic that is independent of the host CPU (13) for controlling access between the host CPU (13) and the storage device (21). A program memory (41) that is independent of the computer memory unalterably stores and provides computer programs for operating the processor (37) in a manner so as to control access to the storage device (21). The security logic comprises logic in bus bridge circuitry . The bus bridge circuitry can be embodied in the south bridge circuit (326) of a computer system (11) or alternatively in a SOC circuit (351) of a HDD. All data access by the host CPU (13) to the data storage device (21) is blocked before initialisation of the security system and is intercepted immediately after the initialisation under the control of the security logic. The security logic effects independent control of the host CPU (13) and configuration of the computer (11) to prevent unauthorised access to the storage device (21) during the interception phase. All users of the computer (11) are authenticated with a prescribed profile of access to the storage device (21) and data access to the storage device remains blocked until a user of the computer (11) is correctly authenticated.