Hardware-Assisted Code Obfuscation for FPGA Soft Microprocessors

Monday, 9 March 2015 at 11:00 in INF 328

Russel Tessier, University of Massachusetts, Amherst, MA, USA

 

Abstract:

Soft microprocessors are vital components of many embedded FPGA systems. As the application domain for FPGAs expands, the security of the software used by soft processors increases in importance. Although software confidentiality approaches (e.g. encryption) are effective, code obfuscation is known to be an effective enhancement that further deters code understanding for attackers. The availability of specialization in FPGAs provides a unique opportunity for code obfuscation on a per-application basis with minimal hardware overhead. I describe a new technique to obfuscate soft microprocessor code which is located outside the FPGA chip in an unprotected area. Our approach provides customizable, data-dependent control flow modification to make it difficult for attackers to easily understand program behavior. The application of the approach to three benchmarks illustrates a control flow cyclomatic complexity increase of about 7x with a modest logic overhead for the soft processor.
 

About the speaker:

Russell Tessier received the B.S. degree in computer and systems engineering from Rensselaer Polytechnic Institute, Troy, NY, USA, in 1989, and the S.M. and Ph.D. degrees in electrical engineering from the Massachusetts Institute of Technology, Cambridge, MA, USA, in 1992 and 1999, respectively. He is currently a professor of electrical and computer engineering with the University of Massachusetts, Amherst, MA. His current research interests include computer architecture, FPGAs, and system verification.