3.1.4 Further document hash_to_F which may collide

This commit is contained in:
Luke Parker 2023-02-23 01:03:53 -05:00
parent cb4ce5e354
commit 686a5ee364
No known key found for this signature in database
3 changed files with 34 additions and 5 deletions

View file

@ -17,8 +17,6 @@ macro_rules! dalek_curve {
) => {
use dalek_ff_group::$Point;
#[derive(Clone, Copy, PartialEq, Eq, Debug, Zeroize)]
pub struct $Ciphersuite;
impl Ciphersuite for $Ciphersuite {
type F = Scalar;
type G = $Point;
@ -37,6 +35,14 @@ macro_rules! dalek_curve {
};
}
/// 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"))]
@ -60,6 +66,14 @@ fn test_ristretto() {
);
}
/// Ciphersuite for Ed25519.
///
/// 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")]

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@ -11,7 +11,7 @@ use minimal_ed448::{scalar::Scalar, point::Point};
use crate::Ciphersuite;
// Re-define Shake256 as a traditional Digest to meet API expectations
/// Shake256, fixed to a 114-byte output, as used by Ed448.
#[derive(Clone, Default)]
pub struct Shake256_114(Shake256);
impl BlockSizeUser for Shake256_114 {
@ -48,6 +48,11 @@ impl FixedOutput for Shake256_114 {
}
impl HashMarker for Shake256_114 {}
/// Ciphersuite for Ed448.
///
/// 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.
#[derive(Clone, Copy, PartialEq, Eq, Debug, Zeroize)]
pub struct Ed448;
impl Ciphersuite for Ed448 {

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@ -20,8 +20,6 @@ macro_rules! kp_curve {
$Ciphersuite: ident,
$ID: literal
) => {
#[derive(Clone, Copy, PartialEq, Eq, Debug, Zeroize)]
pub struct $Ciphersuite;
impl Ciphersuite for $Ciphersuite {
type F = $lib::Scalar;
type G = $lib::ProjectivePoint;
@ -105,6 +103,12 @@ fn test_oversize_dst<C: Ciphersuite>() {
assert_eq!(C::hash_to_F(&oversize_dst, &[]), C::hash_to_F(&actual_dst, &[]));
}
/// Ciphersuite for Secp256k1.
///
/// hash_to_F is implemented via the IETF draft for hash to curve's hash_to_field (v16).
#[cfg(feature = "secp256k1")]
#[derive(Clone, Copy, PartialEq, Eq, Debug, Zeroize)]
pub struct Secp256k1;
#[cfg(feature = "secp256k1")]
kp_curve!("secp256k1", k256, Secp256k1, b"secp256k1");
#[cfg(feature = "secp256k1")]
@ -137,6 +141,12 @@ fn test_secp256k1() {
test_oversize_dst::<Secp256k1>();
}
/// Ciphersuite for P-256.
///
/// hash_to_F is implemented via the IETF draft for hash to curve's hash_to_field (v16).
#[cfg(feature = "p256")]
#[derive(Clone, Copy, PartialEq, Eq, Debug, Zeroize)]
pub struct P256;
#[cfg(feature = "p256")]
kp_curve!("p256", p256, P256, b"P-256");
#[cfg(feature = "p256")]