Efficient Implementation of CRYSTALS-KYBER Key Encapsulation Mechanism on ESP32

Abstract: Kyber, an IND-CCA2-secure lattice-based post-quantum key-encapsulation mechanism, is the winner of the first post-quantum cryptography standardization process of the US National Institute of Standards and Technology. In this work, we provide an efficient implementation of Kyber on ESP32, a very popular microcontroller for Internet of Things applications. We hand-partition the Kyber algorithm to enable utilization of the ESP32 dual-core architecture, which allows us to speed up its execution by 1.21x (keygen), 1.22x (encaps) and 1.20x (decaps). We also explore the possibility of gaining further improvement by utilizing the ESP32 SHA and AES coprocessor and achieve a culminated speed-up of 1.72x (keygen), 1.84x (encaps) and 1.69x (decaps).