# highwayhash-rs

Rust Bindings to AVX2-optimized SIP-like hash functions. This crate offers
bindings to three hash functions implemented in C++
[here](https://github.com/google/highwayhash):

- `siphash`: A portable implementation of the SIP hash function, that is about 2
  times faster than the [reference
  implementation](https://github.com/floodyberry/supercop/blob/master/crypto_auth/siphash24/sse41/siphash.c).
- `siphash13`: A faster but weaker variant of `siphash`.
- `highwayhash64`: A new hash that mixes the inputs using AVX2 instructions. It
  is about 5 times faster than `siphash`. A preliminary cryptanalysis is given
  [here](https://arxiv.org/abs/1612.06257).

For `highwayhash64` there are three implementations: one using AVX2, another one
using SSE4.1 and a third one that is portable by not relying on specific
instruction sets. To profit from the faster implementations, make sure to enable
the instruction sets at compile time using `RUSTFLAGS="-C target-cpu=native"` or
similar.


## Status

The bindings are in an early state. They currently should work on Unix, but are
only tested on Linux. `make` and a C++ compiler are required to build the
underlying C++ library. A nightly Rust compiler is required.


## License

Licensed under either of

 * Apache License, Version 2.0
   ([LICENSE-APACHE](LICENSE-APACHE) or http://www.apache.org/licenses/LICENSE-2.0)
 * MIT license
   ([LICENSE-MIT](LICENSE-MIT) or http://opensource.org/licenses/MIT)

at your option.


## Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted
for inclusion in the work by you, as defined in the Apache-2.0 license, shall be
dual licensed as above, without any additional terms or conditions.