41 lines
1002 B
Rust
41 lines
1002 B
Rust
// -*- mode: rust; -*-
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//
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// This file is part of redjubjub.
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// Copyright (c) 2019-2021 Zcash Foundation
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// See LICENSE for licensing information.
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//
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// Authors:
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// - Deirdre Connolly <deirdre@zfnd.org>
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// - Henry de Valence <hdevalence@hdevalence.ca>
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use crate::Scalar;
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use blake2b_simd::{Params, State};
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/// Provides H^star, the hash-to-scalar function used by RedJubjub.
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pub struct HStar {
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state: State,
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}
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impl Default for HStar {
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fn default() -> Self {
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let state = Params::new()
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.hash_length(64)
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.personal(b"Zcash_RedJubjubH")
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.to_state();
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Self { state }
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}
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}
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impl HStar {
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/// Add `data` to the hash, and return `Self` for chaining.
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pub fn update(&mut self, data: impl AsRef<[u8]>) -> &mut Self {
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self.state.update(data.as_ref());
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self
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}
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/// Consume `self` to compute the hash output.
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pub fn finalize(&self) -> Scalar {
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Scalar::from_bytes_wide(self.state.finalize().as_array())
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}
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}
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