Apparatus and method for securing information entered upon an input device coupled to a universal serial bus

A computer system, bus interface unit and method are provided for securing passwords entered upon a USB input device, such as a USB keyboard. The bus interface unit includes a USB host controller coupled between a USB bus on which the keyboard is configured and another bus on which the system memory is operably connected. The host controller contains registers which keep track of target endpoint addresses of USB devices and, more specifically, address locations (i.e., an input/output address range of to-be-secured data) within those devices. Entry upon a keyboard which falls within the monitored, target endpoint address noted within the host controller will signal the host controller to initiate system management interrupt (SMI), and to execute SMI handler code attributed to SMI. Data from the secured (monitored) target address space is placed within a data buffer of the host controller and eventually to a secured location within system memory.