starkom-poseidon 3.2.2

Starkom's implementation of the Poseidon algebraic hash.
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# Poseidon

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## Overview

This is Starkom's implementation of the [Poseidon algebraic hash](https://eprint.iacr.org/2019/458).

Note that this crate uses version 1 of the permutation. For version 2 see the
[`starkom-poseidon2`](https://crates.io/crates/starkom-poseidon2) crate.

The implementation is generic and works on any prime field.

Configurations for the BLS12-381, Goldilocks, and BlueSky prime fields are provided; the BLS12-381
and BlueSky configurations support T=3 and T=4, while the Goldilocks configurations support T=12 and
T=16.

> [!NOTE]
> All predefined configurations are gated behind feature flags to avoid including all constants in
> all builds. The currently defined feature flags are `bls12_381`, `goldilocks`, and `bluesky`, all
> disabled by default.

## Usage

The following example functions instantiate Poseidon with T=3 and T=4 respectively, squeezing a
single element from the output. Both use a single element for capacity.

```rs
use starkom_bluesky::Scalar;
use starkom_poseidon;

fn hash_t3(inputs: impl IntoIterator<Item = Scalar>) -> Scalar {
    starkom_poseidon::hash::<starkom_poseidon::bluesky::BlueSkyConfig3, Scalar, 3, 2, 1>(inputs)[0]
}

fn hash_t4(inputs: impl IntoIterator<Item = Scalar>) -> Scalar {
    starkom_poseidon::hash::<starkom_poseidon::bluesky::BlueSkyConfig4, Scalar, 4, 3, 1>(inputs)[0]
}
```