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Use GroupEncoding instead of Curve's from_slice/to_bytes

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Increases usage of standardization while expanding dalek_ff_group.

Closes https://github.com/serai-dex/serai/issues/26 by moving 
dfg::EdwardsPoint to only be for the prime subgroup.
This commit is contained in:
Luke Parker
2022-06-28 01:25:26 -04:00
parent ac17645fc8
commit 3de7a76051
14 changed files with 141 additions and 178 deletions
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52
crypto/frost/src/curve/dalek.rs
View File

@@ -1,34 +1,27 @@
use core::convert::TryInto;
use rand_core::{RngCore, CryptoRng};
use sha2::{Digest, Sha512};
use group::{ff::PrimeField, Group};
use dalek_ff_group::Scalar;
use crate::{curve::{CurveError, Curve}, algorithm::Hram};
use crate::{curve::Curve, algorithm::Hram};
macro_rules! dalek_curve {
(
$Curve: ident,
$Hram: ident,
$Point: ident,
$Compressed: ident,
$Table: ident,
$POINT: ident,
$TABLE: ident,
$torsioned: expr,
$ID: literal,
$CONTEXT: literal,
$chal: literal,
$digest: literal,
) => {
use dalek_ff_group::{$Point, $Compressed, $Table, $POINT, $TABLE};
use dalek_ff_group::{$Point, $Table, $POINT, $TABLE};
#[derive(Clone, Copy, PartialEq, Eq, Debug)]
pub struct $Curve;
@@ -75,43 +68,6 @@ macro_rules! dalek_curve {
fn G_len() -> usize {
32
}
fn F_from_slice(slice: &[u8]) -> Result<Self::F, CurveError> {
let scalar = Self::F::from_repr(
slice.try_into().map_err(|_| CurveError::InvalidLength(32, slice.len()))?
);
if !bool::from(scalar.is_some()) {
Err(CurveError::InvalidScalar)?;
}
Ok(scalar.unwrap())
}
fn G_from_slice(slice: &[u8]) -> Result<Self::G, CurveError> {
let bytes = slice.try_into().map_err(|_| CurveError::InvalidLength(32, slice.len()))?;
let point = $Compressed::new(bytes).decompress().ok_or(CurveError::InvalidPoint)?;
// Ban identity
if point.is_identity().into() {
Err(CurveError::InvalidPoint)?;
}
// Ban torsioned points to meet the prime order group requirement
if $torsioned(point) {
Err(CurveError::InvalidPoint)?;
}
// Ban points which weren't canonically encoded
if point.compress().to_bytes() != bytes {
Err(CurveError::InvalidPoint)?;
}
Ok(point)
}
fn F_to_bytes(f: &Self::F) -> Vec<u8> {
f.to_repr().to_vec()
}
fn G_to_bytes(g: &Self::G) -> Vec<u8> {
g.compress().to_bytes().to_vec()
}
}
#[derive(Copy, Clone)]
@@ -130,11 +86,9 @@ dalek_curve!(
Ristretto,
IetfRistrettoHram,
RistrettoPoint,
CompressedRistretto,
RistrettoBasepointTable,
RISTRETTO_BASEPOINT_POINT,
RISTRETTO_BASEPOINT_TABLE,
|_| false,
b"ristretto",
b"FROST-RISTRETTO255-SHA512-v5",
b"chal",
@@ -146,11 +100,9 @@ dalek_curve!(
Ed25519,
IetfEd25519Hram,
EdwardsPoint,
CompressedEdwardsY,
EdwardsBasepointTable,
ED25519_BASEPOINT_POINT,
ED25519_BASEPOINT_TABLE,
|point: EdwardsPoint| !bool::from(point.is_torsion_free()),
b"edwards25519",
b"",
b"",