Optimized implementation of QC-MDPC code-based cryptography

摘要

This paper presents a new enhanced version of the QcBits key encapsulation mechanism, whichis a constant-time implementation of the Niederreiter cryptosystem using QC-MDPC codes. Inthis version, we updated the implementation parameters to meet the 128-bit quantum securitylevel, replaced some of the core algorithms to avoid using slower instructions, vectorized theentire code using the AVX-512 instruction set extension, and applied several other techniquesto achieve a competitive performance level. Our implementation takes 928, 259, and 5008thousand Skylake cycles to perform batch key generation (cost per key), encryption, anduniform decryption, respectively. Comparing with the current state-of-the-art implementationfor QC-MDPC codes, BIKE, our code is 1.9 times faster when decrypting messages.