Asymmetric cryptography enabled by TaO_x-based complementary memristors with tunable pulse dynamics

As the demand for secure communication grows in open and resource-constrained environments, traditional encryption schemes encounter significant challenges, particularly in key management and energy efficiency. To address these limitations, this study introduces a hardware-based asymmetric encryption framework utilizing TaO_x-based complementary memristors. The framework leverages tunable conductance modulation in complementary resistive switching (CRS) devices to optimize the voltage pulse amplitude and interval. This approach facilitates the realization of long-term potentiation (LTP) and long-term depression (LTD) using pulses of the same polarity, thereby enabling the generation of public and private keys. Binary-encoded ASCII data are converted into quantized conductance states using a 2 × 4 CRS crossbar array, ensuring reliable and reversible encryption and decryption directly within memory. Additionally, an SHA-256-based hash algorithm is integrated for identity-based authentication using public keys, eliminating the need for secure channels during the verification process. Our results demonstrate high encryption fidelity, distinct key separation, and strong resistance to unauthorized access, highlighting the potential of TaO_x-based complementary memristors for secure cryptographic applications in next-generation IoT and embedded systems.