Bitstream Fault Injections (BiFI)-Automated Fault Attacks Against SRAM-Based FPGAs

• Published in: IEEE transactions on computers Vol. 67; no. 3; pp. 348 - 360
• Main Authors: Swierczynski, Pawel, Becker, Georg T., Moradi, Amir, Paar, Christof
• Format: Journal Article
• Language: English
• Published: New York IEEE 01-03-2018; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: AES; automated key recovery; bitstream encryption vulnerability; bitstream fault injection; Circuit faults; Cryptography; Encryption; Field programmable gate arrays; FPGA security; Hardware; Table lookup
• ISSN: 0018-9340; 1557-9956
• DOI: 10.1109/TC.2016.2646367

This contribution is concerned with the question whether an adversary can automatically manipulate an unknown FPGA bitstream realizing a cryptographic primitive such that the underlying secret key is revealed. In general, if an attacker has full knowledge about the bitstream structure and can make changes to the target FPGA design, she can alter the bitstream leading to key recovery. However, this requires challenging reverse-engineering steps in practice. We argue that this is a major reason why bitstream fault injection attacks have been largely neglected in the past. In this paper, we show that malicious bitstream modifications are i) much easier to conduct than commonly assumed and ii) surprisingly powerful. We introduce a novel class of bitstream fault injection (BiFI) attacks which does not require any reverse-engineering. Our attacks can be automatically mounted without any detailed knowledge about either the bitstream format or the design of the crypto primitive which is being attacked. Bitstream encryption features do not necessarily prevent our attack if the integrity of the encrypted bitstream is not carefully checked. We have successfully verified the feasibility of our attacks in practice by considering several publicly available AES designs. As target platforms, we have conducted our experiments on Spartan-6 and Virtex-5 Xilinx FPGAs.