Secret sharing and multi-user authentication: From visual cryptography to RRAM circuits

In this era of Internet of Things (IoT), connectivity exists everywhere, among everything (including people) at all times. Therefore, security, trust, and privacy become crucial to the design and implementation of IoT devices [12]. However, it is challenging to build security into IoT devices because most of them are constrained by extremely limited resources such as the battery, memory, and computation power etc. Inspired by the concept of visual cryptography [4] that requires the least amount of computation and a recent work on pure hardware-based single-user authentication [6], we present a novel solution to the secret sharing and multi-user authentication problem. Our solution is built on the observation that non-volatile resistive memories display nice monotonic and additive properties during resistive state transitions. We demonstrate how to design a hardware dependent multi-user authentication protocol using resistive random access memory (RRAM)-based hardware and provide the necessary circuits for the application. Finally, we simulate the proposed circuit to understand the nature of the operation and practical problems that these designs encounter during operation.