1mod error;
2mod field;
3mod shamir;
4mod util;
5
6pub use error::Error;
7use shamir::padding::{pad, unpad};
8
9pub fn split_secret(
10 threshold: u8,
11 share_count: u8,
12 shared_secret: &[u8],
13) -> Result<Vec<Vec<u8>>, error::Error> {
14 let splitter = shamir::Splitter::new(None);
15 let proto_share = shamir::Share::new()?;
16 let shared_secret = pad(shared_secret.into(), 16);
17 let shares = splitter
18 .split_secret(&proto_share, threshold, share_count, &shared_secret)?
19 .into_iter()
20 .map(|s| s.to_u8_vec())
21 .collect::<Result<Vec<_>, _>>()?;
22
23 Ok(shares)
24}
25
26pub fn recover_secret<'a, I>(shares: I) -> Result<Vec<u8>, error::Error>
27where
28 I: IntoIterator<Item = &'a [u8]>,
29{
30 let shares = shares
31 .into_iter()
32 .map(shamir::Share::from_u8_vec)
33 .collect::<Result<Vec<_>, _>>()?;
34
35 let splitter = shamir::Splitter::new(None);
36 let secret = splitter.recover_secret(&shares)?;
37 let secret = unpad(secret)?;
38
39 Ok(secret)
40}
41
42#[cfg(test)]
43mod tests {
44 use super::*;
45 use rand::{prelude::SliceRandom, thread_rng};
46
47 #[test]
48 fn split_recover() -> Result<(), error::Error> {
49 let secret = util::fill_vec_rand(100);
50 let shares = split_secret(5, 10, &secret)?;
51 let mut subset = shares.clone();
52 subset.shuffle(&mut thread_rng());
53 subset.truncate(5);
54 let recovered = recover_secret(subset.iter().map(|s| s.as_slice()))?;
55 assert_eq!(secret, recovered);
56 Ok(())
57 }
58
59 #[test]
60 fn split_recover_empty_secret() -> Result<(), error::Error> {
61 let secret = vec![];
62 let shares = split_secret(5, 10, &secret)?;
63 let mut subset = shares.clone();
64 subset.shuffle(&mut thread_rng());
65 subset.truncate(5);
66 let recovered = recover_secret(subset.iter().map(|s| s.as_slice()))?;
67 assert_eq!(secret, recovered);
68 Ok(())
69 }
70}