Cryptology ePrint Archive: Report 2021/532

Rainbow on Cortex-M4

Tung Chou and Matthias J. Kannwischer and Bo-Yin Yang

Abstract: We present the first Cortex-M4 implementation of the NISTPQC signature finalist Rainbow. We target the Giant Gecko EFM32GG11B which comes with 512 kB of RAM which can easily accommodate the keys of RainbowI. We present fast constant-time bitsliced F_16 multiplication allowing multiplication of 32 field elements in 32 clock cycles. Additionally, we introduce a new way of computing the public map P in the verification procedure allowing vastly faster signature verification. Both the signing and verification procedures of our implementation are by far the fastest among the NISTPQC signature finalists. Signing of rainbowIclassic requires roughly 957 000 clock cycles which 4 faster than the state of the art Dilithium2 implementation and 45 faster than Falcon-512. Verification needs about 239 000 cycles which is 5 and 2 faster respectively. The cost of signing can be further decreased by 20% when storing the secret key in a bitsliced representation.

Category / Keywords: implementation / Rainbow, NISTPQC, Cortex-M4, MQ signatures, finite field arithmetic

Date: received 21 Apr 2021

Contact author: blueprint at crypto tw,matthias@kannwischer eu,by@crypto tw

Available format(s): PDF | BibTeX Citation

Version: 20210423:122854 (All versions of this report)

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