Flashmark: Watermarking of NOR Flash Memories for Counterfeit Detection

Counterfeit electronics represents a significant concern because recycled, over-produced, out-of-spec, or cloned chips can enter globalized supply chains. This paper introduces Flashmark, a technique for watermarking of NOR flash memories for counterfeit detection. Flashmark relies on novel approaches for (a) imprinting watermarks into dedicated blocks of flash memory chips by repeated stressing, thus irreversibly changing physical properties of flash memory cells, and (b) reading out watermarks by sensing the changes in physical properties of flash cells through standard digital interfaces. The paper demonstrates Flashmark on embedded NOR flash memories in a family of low-cost microcontrollers.