serai/crypto/ciphersuite/src/dalek.rs
2023-03-20 20:10:00 -04:00

100 lines
3 KiB
Rust

use zeroize::Zeroize;
use sha2::{Digest, Sha512};
use group::Group;
use dalek_ff_group::Scalar;
use crate::Ciphersuite;
macro_rules! dalek_curve {
(
$feature: literal,
$Ciphersuite: ident,
$Point: ident,
$ID: literal
) => {
use dalek_ff_group::$Point;
impl Ciphersuite for $Ciphersuite {
type F = Scalar;
type G = $Point;
type H = Sha512;
const ID: &'static [u8] = $ID;
fn generator() -> Self::G {
$Point::generator()
}
fn hash_to_F(dst: &[u8], data: &[u8]) -> Self::F {
Scalar::from_hash(Sha512::new_with_prefix(&[dst, data].concat()))
}
}
};
}
/// Ciphersuite for Ristretto.
///
/// hash_to_F is implemented with a naive concatenation of the dst and data, allowing transposition
/// between the two. This means `dst: b"abc", data: b"def"`, will produce the same scalar as
/// `dst: "abcdef", data: b""`. Please use carefully, not letting dsts be substrings of each other.
#[cfg(any(test, feature = "ristretto"))]
#[derive(Clone, Copy, PartialEq, Eq, Debug, Zeroize)]
pub struct Ristretto;
#[cfg(any(test, feature = "ristretto"))]
dalek_curve!("ristretto", Ristretto, RistrettoPoint, b"ristretto");
#[cfg(any(test, feature = "ristretto"))]
#[test]
fn test_ristretto() {
ff_group_tests::group::test_prime_group_bits::<_, RistrettoPoint>(&mut rand_core::OsRng);
assert_eq!(
Ristretto::hash_to_F(
b"FROST-RISTRETTO255-SHA512-v11nonce",
&hex::decode(
"\
81800157bb554f299fe0b6bd658e4c4591d74168b5177bf55e8dceed59dc80c7\
5c3430d391552f6e60ecdc093ff9f6f4488756aa6cebdbad75a768010b8f830e"
)
.unwrap()
)
.to_bytes()
.as_ref(),
&hex::decode("40f58e8df202b21c94f826e76e4647efdb0ea3ca7ae7e3689bc0cbe2e2f6660c").unwrap()
);
}
/// Ciphersuite for Ed25519, inspired by RFC-8032.
///
/// hash_to_F is implemented with a naive concatenation of the dst and data, allowing transposition
/// between the two. This means `dst: b"abc", data: b"def"`, will produce the same scalar as
/// `dst: "abcdef", data: b""`. Please use carefully, not letting dsts be substrings of each other.
#[cfg(feature = "ed25519")]
#[derive(Clone, Copy, PartialEq, Eq, Debug, Zeroize)]
pub struct Ed25519;
#[cfg(feature = "ed25519")]
dalek_curve!("ed25519", Ed25519, EdwardsPoint, b"edwards25519");
#[cfg(feature = "ed25519")]
#[test]
fn test_ed25519() {
ff_group_tests::group::test_prime_group_bits::<_, EdwardsPoint>(&mut rand_core::OsRng);
// Ideally, a test vector from RFC-8032 (not FROST) would be here
// Unfortunately, the IETF draft doesn't provide any vectors for the derived challenges
assert_eq!(
Ed25519::hash_to_F(
b"FROST-ED25519-SHA512-v11nonce",
&hex::decode(
"\
9d06a6381c7a4493929761a73692776772b274236fb5cfcc7d1b48ac3a9c249f\
929dcc590407aae7d388761cddb0c0db6f5627aea8e217f4a033f2ec83d93509"
)
.unwrap()
)
.to_bytes()
.as_ref(),
&hex::decode("70652da3e8d7533a0e4b9e9104f01b48c396b5b553717784ed8d05c6a36b9609").unwrap()
);
}