Security from an unwanted intrusion into a computer system (12) is provided by coupling a host component (10) with a peripheral component (16-18) using a high-speed serial bus (14.1-14.4) having a high-speed physical layer and using features of the bus (14.1-14.4) to implement the security. In an embodiment, the high-speed serial bus (14.1-14.4) has a secondary bus layer that is used to implement a number of the security features of the invention.
