Mecca: A Robust Low-Overhead Puf Using Embedded Memory Array

The generation of unique keys by Integrated Circuits (IC) has important applications in areas such as Intellectual Property (IF) counter-plagiarism and embedded security integration. To this end, Physical Unclonable Functions (PUF) have been proposed to build tamper-resistant hardware by exploiting random process variations. Existing PUFs suffer from increased overhead to the original design due to their specific functions for generating unique keys and/or routing constraints. In this paper, we propose a novel memory-cell based PUF (MECCA PUF), which performs authentication by exploiting the intrinsic process variations in read/write reliability of cells in static memories. The reliability of cells is characterized after manufacturing by inducing temporal failures, such as write and access failures in the cells using a programmable word line duty cycle controller. Since most modern designs already have considerable amount of embedded memory, the proposed approach incurs very little overhead (<1%) compared to existing PUF designs. Simulation results for 1000 chips with 10% inter-die variations show that the PUF provides large choice of challenge-response pairs with high uniqueness (49.9% average inter-die Hamming distance) and excellent reproducibility (0.85% average intra-die Hamming distance).