rvv-keccak

RISC-V Vector Implementation of Keccak hash function.

This repository contains multiple experiments of vectorized implementation of the Keccak function (Keccak-F1600). In particular it contains unrolled scalar C implementations and implementations using RISC-V Vector Extensions.

The implementations are based on C the implementation from https://github.com/XKCP/XKCP/tree/master/Standalone/CompactFIPS202/C.

A blog post described some of the techniques evaluated and summarized the results: https://fprox.substack.com/publish/posts/detail/140028226?referrer=github.

Environment

Building docker image

An environment to build the source contained in this repository can be created using the DockerFile riscv-toolchain.Dockerfile.

docker build  -t riscv:riscv-toolchain -f riscv-toolchain.Dockerfile .

Running the docker image

docker run  -ti --mount type=bind,source="$(pwd)"/,target=/home/app/ riscv:riscv-toolchain

Building and running the benchmark

This repository contains multiple implementations of the Keccak function.

• Baseline very compact implementation in Keccak-more-compact.c
• Optimized (unrolled) compact implementation in Keccak-more-compact-opt.c
• Optimized (unrolled with less memory accesses) compact implementation in Keccak-more-compact-opt-in-regs.c
• Baseline readable implementation in Keccak-readable-and-compact.c
• RVV based implementation in keccak-vector-wrapper.c (actual implementation is in keccak-vector.c)

Those implementations can be selected by setting the KECCAK_SRC and KECCAK_WRAPPER_SRC variables to the corresponding source file when building and running the benchmark. For example:

make sim_bench_keccak KECCAK_SRC=keccak-vector.c KECCAK_WRAPPER_SRC=keccak-vector-wrapper.c CFLAGS="-O3"

running without Zvbb support

By default the benchmark assumes that the target has support for the Zvbb (vector bit manipulation) extension. The source code and the benchmark support disabling this extension:

make clean
make sim_bench_keccak CLANG_EXTRA_EXTS= SPIKE_EXTRA_EXTS= EXTRA_CFLAGS="-DNO_ZVBB_INTRINSICS"

In the code snippet below, use of scalar bit manipulation extensions has also been disabled, to enable it:

make clean
make sim_bench_keccak CLANG_EXTRA_EXTS=_zbb_zbc_zba SPIKE_EXTRA_EXTS=_zbb_zbc_zba EXTRA_CFLAGS="-DNO_ZVBB_INTRINSICS"