Transforming write collisions in block RAMs into security applications

Due to their versatile and generic structure, field programmable gate arrays (FPGA) allow dynamic reconfiguration of their logical resources just by loading configuration files. However, this flexibility also opens up the threat of theft of intellectual property (IP) since these configuration files can be easily extracted and cloned. In this context, the ability to bind a configuration to a specific device is an important step to prevent product counterfeiting. In this paper, we present a novel strategy to identify and authenticate FPGAs in applications using intrinsic, device-specific information (also known as physically unclonable functions). Our solution is based on the output of intentionally induced write collisions in synchronous dual-port block RAM (BRAM). We show that the output of such write collisions can be used to create unique device signatures. In addition to applications for chip identification and authentication, we also propose a solution to efficiently create secret keys on-chip. As a last contribution, we outline how to transform our idea into a circuit for true random number generation (TRNG).