Random stream cipher as a PUF-like identity in FPGA environment

Abstract

Digital Secret Unknown Cipher (SUC) has been proposed in the last decade targeting to counteract the drawbacks of the traditional analog Physical Unclonable Functions (PUF). The SUCs, as pure-digital units, exhibit consistent operation during the whole digital unit's lifetime. This makes SUCs as PUF alternatives attractive for practical creation of clone-resistant units for a broad spectrum of applications especially in automotive and other mass-product cases. In this paper, we propose a novel SUC creation scenario as a random stream cipher to be embedded in Microsemi SmartFusion®2 System on Chip (SoC) FPGAs. The resulting cipher as a Key Stream Generators (KSG) is T-functions-based creating individual and randomized secret-key-streams which are individual for each unit. The proposed SUC-based Random Stream Cipher (RSC-SUC) is a lightweight SUC realization optimized for the SmartFusion®2 SoC FPGA technology. The security analysis and hardware complexity issues of the resulting RSC-SUC structures are also discussed and evaluated.