utility_crypto/
key_conversion.rs

1use crate::{signature, vrf, PublicKey};
2use curve25519_dalek::edwards::{CompressedEdwardsY, EdwardsPoint};
3use curve25519_dalek::ristretto::RistrettoPoint;
4use std::mem::transmute;
5
6pub fn is_valid_staking_key(public_key: &PublicKey) -> bool {
7    // The valid staking key is ED25519, and can be converted to ristretto.
8    match public_key {
9        PublicKey::ED25519(key) => convert_public_key(key).is_some(),
10        _ => false,
11    }
12}
13
14pub fn convert_public_key(key: &signature::ED25519PublicKey) -> Option<vrf::PublicKey> {
15    let ep: EdwardsPoint = CompressedEdwardsY::from_slice(&key.0).ok()?.decompress()?;
16    // All properly generated public keys are torsion-free. RistrettoPoint type can handle some values that are not torsion-free, but not all.
17    if !ep.is_torsion_free() {
18        return None;
19    }
20    // Unfortunately, dalek library doesn't provide a better way to do this.
21    let rp: RistrettoPoint = unsafe { transmute(ep) };
22    Some(vrf::PublicKey(rp.compress().to_bytes(), rp))
23}
24
25pub fn convert_secret_key(key: &signature::ED25519SecretKey) -> vrf::SecretKey {
26    let b = <&[u8; 32]>::try_from(&key.0[..32]).unwrap();
27    let s = ed25519_dalek::hazmat::ExpandedSecretKey::from(b).scalar;
28    vrf::SecretKey::from_scalar(s)
29}
30
31#[cfg(test)]
32mod tests {
33    use super::*;
34
35    #[test]
36    fn test_conversion() {
37        for _ in 0..10 {
38            let kk = signature::SecretKey::from_random(signature::KeyType::ED25519);
39            let pk = match kk.public_key() {
40                signature::PublicKey::ED25519(k) => k,
41                _ => unreachable!(),
42            };
43            let sk = match kk {
44                signature::SecretKey::ED25519(k) => k,
45                _ => unreachable!(),
46            };
47            assert_eq!(
48                convert_secret_key(&sk).public_key().clone(),
49                convert_public_key(&pk).unwrap()
50            );
51        }
52    }
53}
utility_crypto/key_conversion.rs

utility_crypto/
key_conversion.rs
