WATERMARCH: IP Protection Through Authenticated Obfuscation in FPGA Bitstreams
Brooks Olney, Robert Karam · IEEE Embedded Systems Letters · 2020
Field programmable gate array (FPGA) bitstreams contain information on the functionality of all hardware intellectual property (IP) cores used in a given design, so if an attacker gains access to the bitstream, they can mount attacks on the IP. Various mechanisms have been proposed to protect IP from reverse engineering and theft. However, there are no examples of IP obfuscation in FPGA bitstreams that also intrinsically enable tamper detection and authentication at no additional hardware cost. In this letter, we propose a mutable architecture-based watermarking scheme called WATERMARCH, a novel technique of authenticated obfuscation utilizing a hash-based message authentication code (HMAC) to cryptographically mesh the obfuscation and watermark with the original design, with no additional overhead beyond the underlying obfuscation method. While collaboration between the IP owner and FPGA vendor is necessary to facilitate parsing of the bitstream, once the bitstream is parsable, the watermark can be extracted to prove authorship of the IP or confirm the presence of malicious IP modification, providing tremendous benefits to both IP owners and end users.