Quantum Dots and Perovskites-Based Physically Unclonable Functions for Binary and Ternary Keys via Optical-to-Electrical Conversion

Physically unclonable functions (PUFs) are hardware-based security keys that are considered one of the most promising next-generation security solutions for intelligent systems. Numerous studies have reported on optical and electrical PUFs; however, these PUFs exhibit certain limitations, such as complicated readout systems and low encoding capacity. Optoelectronic PUFs capable of generating cryptographic multikey using electrical signals that are dependent on the wavelength of the incident light are proposed in this study. This wavelength-dependent response is enabled by the random deposition of lead sulfide quantum dots and methylammonium lead iodide perovskites, which absorb visible and IR light, respectively. Optical, electrical, and morphological analyses are conducted to assess the randomness of randomly distributed films fabricated by sequential spray coating and dynamic spin coating. Binary keys are generated using the ranking mechanism, and their uniqueness and stability are evaluated through inter- and intra-hamming distance (HD) analyses, with both approaching near-ideal values. Furthermore, a ternary key generation mechanism that improves the encoding capacity is introduced. The inter- and intra-HD values for the ternary keys also approach near-ideal values. The proposed optoelectronic PUFs exhibit substantial potential for securing the Internet of Things devices.