A computing system and method providing normal security services and high security services are disclosed. The computing system includes hardware resources, a processor core and an access right checker. The hardware resources are grouped into resource security levels. The processor, switching between a normal security and a high security state, assigns a user access right to a request. In comparison with the normal security state, user access right assigned in the high security state further allows the request to use the hardware resources of a higher resource security level. According to the assigned user access right and the resource security levels of required hardware resources of the request, the access right checker determines whether the request has the authority to use the hardware resources, and thereby, the access right checker executes the request or responds the issued request with an exception.