Pennsylvania State University,
Keywords: 2D materials, random numbers, Internet of things, hardware security
Summary:Information security is critical for most Internet of Things (IoT) edge devices that thrive on data. While software-based encryption and decryption schemes are powerful, the computational and energy requirements can be limiting for many resource-constrained IoT applications. In contrast, hardware-based security schemes are more compelling for such IoT devices and true random number generators (TRNGs) constitute the basic building blocks for such hardware security. While conventional silicon-based and emerging nanomaterial-based TRNGs have been demonstrated in recent years, most necessitate extensive peripherals, which incur additional and undesired energy and area overhead. Here, we introduce a peripheral-free TRNG based on a cascaded three-stage inverter (TSI) made using monolayer MoS2 field-effect transistors (FETs). We exploit stochastic charge trapping and detrapping phenomena at and/or near the MoS2/dielectric interface as the source of randomness and convert it into random bits using the TSI. The generated bits pass the NIST randomness tests without any post-processing ensuring their true random nature. Furthermore, the secure keys generated utilizing these random bits offer high entropy, near-ideal correlation, uniformity, and necessary hamming distance. The energy expenditure for the TRNG was found to be as frugal as 30pJ/bit. Our experimental demonstration highlights the potential of atomically thin 2D materials in developing low-power TRNG.