Patent ID: 8156346

Claim:
A keyboard-input information-security apparatus comprising: an interrupt-descriptor table for storing a list of addresses of functions for handling interrupts, and storing an address of a secure input-interrupt service routine at a specific location in an address area for an operating-system input interrupt-service routine supported by an operating system; a secure input-device driver for changing keyboard-interrupt-vector information to invoke the address of the secure input interrupt-service routine when a keyboard interrupt is generated by a keyboard-input device, and receiving and encoding data input via the keyboard-input device based on the address of the secure input interrupt-service routine; and a secure input unit for delivering the encoded data from the secure input-device driver to an application program, wherein the secure input-device driver sets a GD (thirteenth) bit of a debug register DR 7 among debug registers DR 0 to DR 7 to a specific value and sets a keyboard input/output port in at least one of registers DR 0 to DR 3 in order to defend against a port-polling attack, and wherein when a security-exception handler is registered in a vector number of the interrupt-descriptor table corresponding to the specific value and the debug register is accessed, an exception occurs and the registered security-exception handler is invoked, and wherein the security-exception handler analyzes the debug register DR 6 among the debug registers, determines whether an accessing program is an authorized program or an unauthorized program depending on association with the GD bit, and controls to permit or block the access depending on the determination result.