In accordance with one aspect of the current invention, the system comprises a memory for storing instruction sequences by which the processor-based system is processed, where the memory includes a physical memory and a virtual memory. The system also comprises a processor for executing the stored instruction sequences. The stored instruction sequences include process acts to cause the processor to: map a plurality of predetermined instruction sequences from the physical memory to the virtual memory, determine an offset to one of the plurality of predetermined instruction sequences in the virtual memory, receive an instruction to execute the one of the plurality of predetermined instruction sequences, transfer control to the one of the plurality of predetermined instruction sequences, and process the one of the plurality of predetermined instruction sequences from the virtual memory. In accordance with another aspect of the present invention, the system includes an access driver to generate a service request to utilize BIOS services such that the service request contains a service request signature created using a private key in a cryptographic key pair. The system also includes an interface to verify the service request signature using a public key in the cryptographic key pair to ensure integrity of the service request.