30 lines
1.0 KiB
Rust
30 lines
1.0 KiB
Rust
use vsss_rs::Gf256;
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#[derive(Debug, thiserror::Error)]
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pub enum ShamirError {
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#[error("Failed to split key: {0}")]
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Split(String),
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#[error("Failed to combine shares: {0}")]
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Combine(String),
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}
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/// Split `key` into `total` shares where any `threshold` shares can reconstruct it.
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/// Each returned Vec<u8> is a share with format [`identifier_byte`, `value_bytes`...].
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pub fn split_key(
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threshold: usize,
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total: usize,
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key: &[u8; 32],
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rng: impl rand_core::RngCore + rand_core::CryptoRng,
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) -> Result<Vec<Vec<u8>>, ShamirError> {
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Gf256::split_array(threshold, total, key.as_slice(), rng)
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.map_err(|e| ShamirError::Split(format!("{e:?}")))
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}
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/// Reconstruct the secret from `threshold` or more shares.
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pub fn combine_shares(shares: &[Vec<u8>]) -> Result<[u8; 32], ShamirError> {
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let bytes = Gf256::combine_array(shares)
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.map_err(|e| ShamirError::Combine(format!("{e:?}")))?;
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<[u8; 32]>::try_from(bytes.as_slice())
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.map_err(|_| ShamirError::Combine("unexpected reconstructed key length".to_owned()))
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}
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