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newpavlov merged 2 commits into from
Mar 16, 2026
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sha2: tweak backend docs #800

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sha2: tweak backend docs
newpavlov Mar 16, 2026
8ee0f81
fix backend name
newpavlov Mar 16, 2026
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13 changes: 6 additions & 7 deletions sha2/README.md
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Expand Up @@ -63,20 +63,19 @@ This crate supports the following backends:
- `aarch64-sha2`: uses the AArch64 `sha2` extension, fallbacks to the `soft` backend
if the extension is not available
- `loongarch64-asm`: `asm!`-based implementation for LoongArch64 targets
- `riscv-zknh`: uses the RISC-V `Zknh` scalar crypto extension (experimental)
- `riscv-zknh-compact`: same as `riscv_zknh` but does not unroll rounds (experimental)
- `riscv-zknh`: uses the RISC-V `Zknh` scalar crypto extension. Experimental,
requires Nightly compiler and to enable `Zknh` and `Zbkb` (or `Zbb`)
target features at compile time.
- `riscv-zknh-compact`: same as `riscv-zknh` but does not unroll rounds.
- `wasm32-simd`: uses the WASM `simd128` extension
- `x86-shani`: uses the x86 SHA-NI extension, fallbacks to the `soft` backend
if the extension is not available (SHA-256 only)
- `x86-avx2`: uses the x86 AVX2 extension, fallbacks to the `soft` backend
if the extension is not available (SHA-512 only)

You can force backend selection using the `sha2_backend` configuration flag. It can be enabled
using either environment variable (e.g. `RUSTFLAGS='--cfg sha2_backend="soft"' cargo build`), or
by modifying your `.cargo/config.toml` file. Currently the flag supports the following values:
`soft`, `soft-compact`, `riscv-zknh`, and `riscv-zknh-compact`.

Note that the RISC-V backends are experimental and require Nightly compiler.
using either environment variable (e.g. `RUSTFLAGS='--cfg sha2_backend="soft"'`),
or by modifying your `.cargo/config.toml` file.

## License

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