Optimized Implementation of SIKE Round 2 on 64-bit ARM Cortex-A Processors

In this work, we present the first highly-optimized implementation of Supersingular Isogeny Key Encapsulation (SIKE) submitted to NIST's second round of post quantum standardization process, on 64-bit ARMv8 processors. To the best of our knowledge, this work is the first optimized implementation of SIKE round 2 on 64-bit ARM over SIKEp434 and SIKEp610. The proposed library is explicitly optimized for these two security levels and provides constant-time implementation of the SIKE mechanism on ARMv8-powered embedded devices. We adapt different optimization techniques to reduce the total number of underlying arithmetic operations on the field level. In particular, benchmark results on embedded processors equipped with ARM Cortex-A55@1.766GHz and ARM Cortex-A75@2.803GHz show that the entire SIKE round 2 Key Encapsulation Mechanism (KEM) takes only 98.6 ms and 85.3ms at NIST's security level 1, respectively. We also evaluated the compressed version of NIST's security level 1, which requires 134.7 ms and 113.7 ms for Cortex-A55 and Cortex-A75, respectively. Considering SIKE's extremely small key size in comparison to other post-quantum cryptography candidates, our result implies that SIKE is one of the promising candidates for key encapsulation mechanism on embedded devices in the quantum era.