An Alternative Approach for SIDH Arithmetic

In this paper, we present new algorithms for the field arithmetic layers of supersingular isogeny Diffie-Hellman; one fifteen remaining candidates in NIST post-quantum standardization process. Our approach uses a polynomial representation elements together with mechanisms to keep coefficients within bounds during operations. We timings and comparisons SIKEp503 suggest novel 736-bit prime that offers \(1.17\times \) speedup compared SIKEp751 similar level security.