26 lines
665 B
Rust
26 lines
665 B
Rust
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// SPDX-License-Identifier: MIT OR Apache-2.0
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// Copyright (c) VexaHub and contributors.
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use core::iter;
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use digest::Output;
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use crate::common::{Dst, Mode, STR_HASH_TO_GROUP, finalize_after_unblind};
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use crate::{CipherSuite, Group};
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pub(crate) fn prf<CS: CipherSuite>(
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input: &[u8],
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key: <CS::Group as Group>::Scalar,
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mode: Mode,
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) -> Output<CS::Hash> {
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let dst = Dst::new::<CS, _>(STR_HASH_TO_GROUP, mode);
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let point = CS::Group::hash_to_curve::<CS::Hash>(&[input], &dst.as_dst()).unwrap();
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let res = point * &key;
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finalize_after_unblind::<CS, _, _>(iter::once((input, res)))
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.next()
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.unwrap()
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.unwrap()
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}
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