International Association for Cryptologic Research

International Association
for Cryptologic Research


Paper: An Alternative Approach for SIDH Arithmetic

Cyril Bouvier
Laurent Imbert
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Abstract: In this paper, we present new algorithms for the field arithmetic layers of supersingular isogeny Diffie-Hellman; one of the fifteen remaining candidates in the NIST post-quantum standardization process. Our approach uses a polynomial representation of the field elements together with mechanisms to keep the coefficients within bounds during the arithmetic operations. We present timings and comparisons for SIKEp503 and suggest a novel 736-bit prime that offers a 1.17x speedup compared to SIKEp751 for a similar level of security.
  title={An Alternative Approach for SIDH Arithmetic},
  booktitle={Public-Key Cryptography - PKC 2021},
  author={Cyril Bouvier and Laurent Imbert},