Secure access to peripheral devices over a bus

To provide a device and a method for secure access of a host device to a peripheral device via a bus.SOLUTION: In a device and a method for secure access to a peripheral device via a bus, a security device 36 comprises an interface 40 and a processor 44. The interface 40 is set to be connected to a bus 32 which provides service to one or more peripheral devices 28. Transmission of the bus 32 comprises (i) one or more dedicated signals each of which is dedicated to mutually corresponding one of one or more peripheral devices 28, and (ii) one or more common signals which are shared among one or more peripheral devices which receive service from the bus. The processor is connected to the bus, and functions as an additional device other than one or more peripheral devices, and interrupts a dedicated signal related to a specific peripheral device, and thus, interrupts transaction of a bus master device 24 which attempts to access the specific peripheral device on the bus.SELECTED DRAWING: Figure 1