Post-Quantum Signatures on RISC-V with Hardware Acceleration

CRYSTALS-Dilithium and Falcon are digital signature algorithms based on cryptographic lattices, that are considered secure even if large-scale quantum computers will be able to break conventional public-key cryptography. Both schemes are third round candidates in the ongoing NIST post-quantum competition. In this work, we present a RISC-V HW/SW codesign that aims to combine the advantages of software- and hardware implementations, i.e. flexibility and performance. It shows the use of flexible hardware accelerators, which have been previously used for Public-Key Encryption (PKE) and Key-Encapsulation Mechanism (KEM), for post-quantum signatures. It is optimized for Dilithium as a generic signature scheme but also accelerates applications that require fast verification of Falcon’s compact signatures. We provide a comparison with previous works showing that for Dilithium and Falcon, cycle counts are significantly reduced, such that our design is faster than previous software implementations or other HW/SW codesigns. In addition to that, we present a compact Globalfoundries 22nm ASIC design that runs at 800MHz. By using hardware acceleration, energy consumption for Dilithium is reduced by up to 92 . 2%, and up to 67 . 5% for Falcon’s signature verification.