Security Checkers: Detecting processor malicious inclusions at runtime

To counter the growing threat of malicious subversions to the design of a microprocessor, there is a great need for simple, automated methods for detecting such malevolent changes. Based on the adoption of the Property Specification Language (PSL) for behavioral verification, and the advent of tools for automatically generating synthesizable hardware design language (HDL) constructs for verifying a PSL assertion, we propose a new method called Security Checkers, which uses security-focused PSL assertions to create hardware design units for detecting malicious inclusions at runtime. We describe the process flow for creating Security Checkers and demonstrate by example how they can be used to detect malicious inclusions in a processor design. Because the checkers can be used in simulation, FPGA emulation, or as part of a fabricated design, we illustrate how this technique can be used to detect malicious inclusions over a much broader segment of the processor development lifecycle, compared to existing methods.