Analytic and simulation results of a Gaussian analog random constant based on resistance dispersion

Physically Unclonable Constants (PUCs) are a special type of Physically Unclonable Functions (PUFs) and they can be used to embed secret bit-strings in chips. Most PUCs are an array of cells where each cell is a digital circuit that evolve spontaneously toward one of two states, the chosen state being function of random manufacturing process variations. In this paper we propose a building block for new PUF/PUC that we call Analog Random Constant (ARC). The output of an ARC is an analog value randomly selected at manufacturing time. An ARC can be used to build a PUF/PUC by digitizing its output and suitably processing the digital value. The ratio behind this approach is that the ARC output has the potential of providing several random bits, reducing the required footprint. Preliminary theoretical analysis and simulation results are presented. The proposed APUC has interesting performances (e.g., it can provide up to 5 bits per cell) that grant for further investigation.