Paper 2020/410

Supersingular Isogeny Key Encapsulation (SIKE) Round 2 on ARM Cortex-M4

Hwajeong Seo, Mila Anastasova, Amir Jalali, and Reza Azarderakhsh


We present the first practical software implementation of Supersingular Isogeny Key Encapsulation (SIKE) round 2, targeting NIST's 1, 2, 3, and 5 security levels on 32-bit ARM Cortex-M4 microcontrollers. The proposed library introduces a new speed record of all SIKE Round 2 protocols with reasonable memory consumption on the low-end target platforms. We achieved this record by adopting several state-of-the-art engineering techniques as well as highly-optimized hand-crafted assembly implementation of finite field arithmetic. In particular, we carefully redesign the previous optimized implementations of finite field arithmetic on the 32-bit ARM Cortex-M4 platform and propose a set of novel techniques which are explicitly suitable for SIKE primes. The benchmark result on STM32F4 Discovery board equipped with 32-bit ARM Cortex-M4 microcontrollers shows that entire key encapsulation and decapsultation over SIKEp434 take about 184 million clock cycles (i.e. 1.09 seconds @168MHz). In contrast to the previous optimized implementation of the isogeny-based key exchange on low-end 32-bit ARM Cortex-M4, our performance evaluation shows feasibility of using SIKE mechanism on the target platform. In comparison to the most of the post-quantum candidates, SIKE requires an excessive number of arithmetic operations, resulting in significantly slower timings. However, its small key size makes this scheme as a promising candidate on low-end microcontrollers in the quantum era by ensuring the lower energy consumption for key transmission than other schemes.

Available format(s)
Publication info
Preprint. MINOR revision.
Isogeny-based cryptographyARMPost-quantum cryptography
Contact author(s)
razarderakhsh @ fau edu
hwajeong84 @ gmail com
2020-04-14: revised
2020-04-13: received
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Creative Commons Attribution


      author = {Hwajeong Seo and Mila Anastasova and Amir Jalali and Reza Azarderakhsh},
      title = {Supersingular Isogeny Key Encapsulation (SIKE) Round 2 on ARM Cortex-M4},
      howpublished = {Cryptology ePrint Archive, Paper 2020/410},
      year = {2020},
      note = {\url{}},
      url = {}
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