A High-Performance SIKE Hardware Accelerator

Abstract

Supersingular isogeny key encapsulation (SIKE) is a promising candidate in the NIST postquantum cryptography (PQC) standardization process, which has the smallest key lengths. It is the only isogeny-based cryptographic scheme in the NIST list that leverages the traditional elliptic curve cryptography (ECC) arithmetic; however, the high computational complexity is one of its limiting factors. In this work, we proposed a high-performance hardware architecture for the SIKE protocol. The architecture includes an improved multiplier based on the high-performance finite field multiplication (HFFM) algorithm which is 15%–20.7% faster than the previous multiplier based on the HFFM algorithm and a unified adder/subtractor with radix <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$3^{b}$ </tex-math></inline-formula> . In addition, it also comprises an efficient scheduler strategy that decomposes all the functions of SIKE into finite field <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$F_{p}$ </tex-math></inline-formula> and then effectively schedules through optimized multiplication chains for maximal performance. The proposed architecture is synthesized and implemented on Xilinx Virtex-7 FPGA for all the four variants of SIKE having security levels from 1 to 5 and achieved 2.6%–7.8% faster speeds as well as consumed less equivalent number of slices (ENS) than the state-of-the-art designs. In the comparison of area and time (AT), the proposed architecture is 14.2%–34.5% lower than the previous architecture.