1use ark_ff::PrimeField;
 2use digest::Digest;
 3impl ark_std::error::Error for Error {}
 4use ark_crypto_primitives::sponge::poseidon::{find_poseidon_ark_and_mds, PoseidonConfig};
 5
 6pub mod ed_on_bn254_twist;
 7pub mod eddsa;
 8pub mod signature;
 9
10#[cfg(feature = "r1cs")]
11pub mod constraints;
12
13pub use eddsa::*;
14
15pub(crate) fn from_digest<F: PrimeField, D: Digest>(digest: D) -> F {
16    let bytes = digest.finalize();
17    F::from_le_bytes_mod_order(&bytes)
18}
19
20#[derive(Clone, Copy, Debug, Eq, PartialEq)]
21pub enum Error {
22    Coordinates,
23    Verify,
24    BadDigestOutput,
25}
26
27impl core::fmt::Display for Error {
28    fn fmt(&self, f: &mut core::fmt::Formatter) -> core::fmt::Result {
29        match *self {
30            Error::Coordinates => write!(f, "Could not obtain the coordinates of a point"),
31            Error::Verify => write!(f, "Signature verification failed"),
32            Error::BadDigestOutput => write!(f, "Bad digest output size"),
33        }
34    }
35}
36
37/// Generates poseidon constants and returns the config
38pub fn poseidon_config<F: PrimeField>(
39    rate: usize,
40    full_rounds: usize,
41    partial_rounds: usize,
42) -> PoseidonConfig<F> {
43    let prime_bits = F::MODULUS_BIT_SIZE as u64;
44    let (ark, mds) = find_poseidon_ark_and_mds(
45        prime_bits,
46        rate,
47        full_rounds as u64,
48        partial_rounds as u64,
49        0,
50    );
51    PoseidonConfig::new(full_rounds, partial_rounds, 5, mds, ark, rate, 1)
52}
53
54#[cfg(test)]
55mod test {
56    use ark_crypto_primitives::sponge::Absorb;
57    use ark_ec::twisted_edwards::TECurveConfig;
58    use ark_ff::PrimeField;
59    use digest::Digest;
60    use rand_core::OsRng;
61
62    use super::poseidon_config;
63    use crate::SigningKey;
64
65    fn run_test<TE: TECurveConfig + Clone, D: Digest>()
66    where
67        TE::BaseField: Absorb + PrimeField,
68    {
69        let poseidon = poseidon_config::<TE::BaseField>(4, 8, 55);
70        let signing_key = SigningKey::<TE>::generate::<D>(&mut OsRng).unwrap();
71        let message_raw = b"xxx yyy <<< zzz >>> bunny";
72        let message = TE::BaseField::from_le_bytes_mod_order(message_raw);
73        let signature = signing_key.sign::<D>(&poseidon, &message).unwrap();
74        let public_key = signing_key.public_key();
75        public_key.verify(&poseidon, &message, &signature).unwrap();
76    }
77
78    #[test]
79    fn test_eddsa() {
80        run_test::<ark_ed_on_bn254::EdwardsConfig, sha2::Sha512>();
81        run_test::<ark_ed_on_bn254::EdwardsConfig, blake2::Blake2b512>();
82        run_test::<crate::ed_on_bn254_twist::EdwardsConfig, sha2::Sha512>();
83        run_test::<ark_ed_on_bls12_381::EdwardsConfig, sha2::Sha512>();
84        run_test::<ark_ed_on_bls12_381_bandersnatch::EdwardsConfig, sha2::Sha512>();
85    }
86}