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ecdsa: use Reduce::reduce_bytes #643

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Merged
tarcieri merged 1 commit into from
Jan 31, 2023
Merged

ecdsa: use Reduce::reduce_bytes #643

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3 changes: 1 addition & 2 deletions Cargo.lock
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3 changes: 3 additions & 0 deletions Cargo.toml
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Original file line number Diff line number Diff line change
Expand Up @@ -9,3 +9,6 @@ members = [

[profile.dev]
opt-level = 2

[patch.crates-io.elliptic-curve]
git = "https://github.com/RustCrypto/traits.git"
20 changes: 10 additions & 10 deletions ecdsa/src/hazmat.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -53,7 +53,7 @@ pub trait SignPrimitive<C>:
+ Into<FieldBytes<C>>
+ IsHigh
+ PrimeField<Repr = FieldBytes<C>>
+ Reduce<C::Uint>
+ Reduce<C::Uint, Bytes = FieldBytes<C>>
+ Sized
where
C: PrimeCurve + CurveArithmetic + CurveArithmetic<Scalar = Self>,
Expand Down Expand Up @@ -84,7 +84,7 @@ where
return Err(Error::new());
}

let z = <Self as Reduce<C::Uint>>::reduce(C::decode_field_bytes(z));
let z = <Self as Reduce<C::Uint>>::reduce_bytes(z);

// Compute scalar inversion of 𝑘
let k_inv = Option::<Scalar<C>>::from(k.invert()).ok_or_else(Error::new)?;
Expand All @@ -94,7 +94,7 @@ where

// Lift x-coordinate of 𝑹 (element of base field) into a serialized big
// integer, then reduce it into an element of the scalar field
let r = Self::reduce(C::decode_field_bytes(&R.x()));
let r = Self::reduce_bytes(&R.x());

// Compute 𝒔 as a signature over 𝒓 and 𝒛.
let s = k_inv * (z + (r * self));
Expand Down Expand Up @@ -132,14 +132,15 @@ where
Self: From<ScalarPrimitive<C>>,
D: Digest + BlockSizeUser + FixedOutput<OutputSize = FieldBytesSize<C>> + FixedOutputReset,
{
let k = rfc6979::generate_k::<D, FieldBytesSize<C>>(
let k = Scalar::<C>::from_repr(rfc6979::generate_k::<D, _>(
&self.to_repr(),
&C::encode_field_bytes(&C::ORDER),
z,
ad,
);
let k = ScalarPrimitive::<C>::new(C::decode_field_bytes(&k)).unwrap();
self.try_sign_prehashed::<Self>(k.into(), z)
))
.unwrap();

self.try_sign_prehashed::<Self>(k, z)
}
}

Expand All @@ -152,7 +153,6 @@ where
pub trait VerifyPrimitive<C>: AffineXCoordinate<FieldRepr = FieldBytes<C>> + Copy + Sized
where
C: PrimeCurve + CurveArithmetic<AffinePoint = Self> + CurveArithmetic,
Scalar<C>: Reduce<C::Uint>,
SignatureSize<C>: ArrayLength<u8>,
{
/// Verify the prehashed message against the provided signature
Expand All @@ -163,7 +163,7 @@ where
/// CRYPTOGRAPHICALLY SECURE DIGEST ALGORITHM!!!
/// - `sig`: signature to be verified against the key and message
fn verify_prehashed(&self, z: &FieldBytes<C>, sig: &Signature<C>) -> Result<()> {
let z = Scalar::<C>::reduce(C::decode_field_bytes(z));
let z = Scalar::<C>::reduce_bytes(z);
let (r, s) = sig.split_scalars();
let s_inv = *s.invert();
let u1 = z * s_inv;
Expand All @@ -177,7 +177,7 @@ where
.to_affine()
.x();

if *r == Scalar::<C>::reduce(C::decode_field_bytes(&x)) {
if *r == Scalar::<C>::reduce_bytes(&x) {
Ok(())
} else {
Err(Error::new())
Expand Down
22 changes: 7 additions & 15 deletions ecdsa/src/recovery.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -13,7 +13,7 @@ use {
use {
crate::{hazmat::VerifyPrimitive, VerifyingKey},
elliptic_curve::{
ops::LinearCombination,
ops::{LinearCombination, Reduce},
point::DecompressPoint,
sec1::{self, FromEncodedPoint, ToEncodedPoint},
AffinePoint, FieldBytesSize, Group, PrimeField, ProjectivePoint,
Expand All @@ -28,9 +28,7 @@ use {
Signature, SignatureSize,
},
elliptic_curve::{
generic_array::ArrayLength,
ops::{Invert, Reduce},
CurveArithmetic, PrimeCurve, Scalar,
generic_array::ArrayLength, ops::Invert, CurveArithmetic, PrimeCurve, Scalar,
},
signature::digest::Digest,
};
Expand Down Expand Up @@ -103,7 +101,6 @@ impl RecoveryId {
AffinePoint<C>:
DecompressPoint<C> + FromEncodedPoint<C> + ToEncodedPoint<C> + VerifyPrimitive<C>,
FieldBytesSize<C>: sec1::ModulusSize,
Scalar<C>: Reduce<C::Uint>,
SignatureSize<C>: ArrayLength<u8>,
{
Self::trial_recovery_from_digest(verifying_key, C::Digest::new_with_prefix(msg), signature)
Expand All @@ -123,7 +120,6 @@ impl RecoveryId {
AffinePoint<C>:
DecompressPoint<C> + FromEncodedPoint<C> + ToEncodedPoint<C> + VerifyPrimitive<C>,
FieldBytesSize<C>: sec1::ModulusSize,
Scalar<C>: Reduce<C::Uint>,
SignatureSize<C>: ArrayLength<u8>,
{
Self::trial_recovery_from_prehash(verifying_key, &digest.finalize(), signature)
Expand All @@ -142,7 +138,6 @@ impl RecoveryId {
AffinePoint<C>:
DecompressPoint<C> + FromEncodedPoint<C> + ToEncodedPoint<C> + VerifyPrimitive<C>,
FieldBytesSize<C>: sec1::ModulusSize,
Scalar<C>: Reduce<C::Uint>,
SignatureSize<C>: ArrayLength<u8>,
{
for id in 0..=Self::MAX {
Expand Down Expand Up @@ -177,7 +172,7 @@ impl From<RecoveryId> for u8 {
impl<C> SigningKey<C>
where
C: PrimeCurve + CurveArithmetic + DigestPrimitive,
Scalar<C>: Invert<Output = CtOption<Scalar<C>>> + Reduce<C::Uint> + SignPrimitive<C>,
Scalar<C>: Invert<Output = CtOption<Scalar<C>>> + SignPrimitive<C>,
SignatureSize<C>: ArrayLength<u8>,
{
/// Sign the given message prehash, returning a signature and recovery ID.
Expand Down Expand Up @@ -210,7 +205,7 @@ impl<C, D> DigestSigner<D, (Signature<C>, RecoveryId)> for SigningKey<C>
where
C: PrimeCurve + CurveArithmetic + DigestPrimitive,
D: Digest,
Scalar<C>: Invert<Output = CtOption<Scalar<C>>> + Reduce<C::Uint> + SignPrimitive<C>,
Scalar<C>: Invert<Output = CtOption<Scalar<C>>> + SignPrimitive<C>,
SignatureSize<C>: ArrayLength<u8>,
{
fn try_sign_digest(&self, msg_digest: D) -> Result<(Signature<C>, RecoveryId)> {
Expand All @@ -222,7 +217,7 @@ where
impl<C> PrehashSigner<(Signature<C>, RecoveryId)> for SigningKey<C>
where
C: PrimeCurve + CurveArithmetic + DigestPrimitive,
Scalar<C>: Invert<Output = CtOption<Scalar<C>>> + Reduce<C::Uint> + SignPrimitive<C>,
Scalar<C>: Invert<Output = CtOption<Scalar<C>>> + SignPrimitive<C>,
SignatureSize<C>: ArrayLength<u8>,
{
fn sign_prehash(&self, prehash: &[u8]) -> Result<(Signature<C>, RecoveryId)> {
Expand All @@ -234,7 +229,7 @@ where
impl<C> Signer<(Signature<C>, RecoveryId)> for SigningKey<C>
where
C: PrimeCurve + CurveArithmetic + DigestPrimitive,
Scalar<C>: Invert<Output = CtOption<Scalar<C>>> + Reduce<C::Uint> + SignPrimitive<C>,
Scalar<C>: Invert<Output = CtOption<Scalar<C>>> + SignPrimitive<C>,
SignatureSize<C>: ArrayLength<u8>,
{
fn try_sign(&self, msg: &[u8]) -> Result<(Signature<C>, RecoveryId)> {
Expand All @@ -249,7 +244,6 @@ where
AffinePoint<C>:
DecompressPoint<C> + FromEncodedPoint<C> + ToEncodedPoint<C> + VerifyPrimitive<C>,
FieldBytesSize<C>: sec1::ModulusSize,
Scalar<C>: Reduce<C::Uint>,
SignatureSize<C>: ArrayLength<u8>,
{
/// Recover a [`VerifyingKey`] from the given message, signature, and
Expand Down Expand Up @@ -290,9 +284,7 @@ where
recovery_id: RecoveryId,
) -> Result<Self> {
let (r, s) = signature.split_scalars();
let z = <Scalar<C> as Reduce<C::Uint>>::reduce(C::decode_field_bytes(&bits2field::<C>(
prehash,
)?));
let z = <Scalar<C> as Reduce<C::Uint>>::reduce_bytes(&bits2field::<C>(prehash)?);
let R = AffinePoint::<C>::decompress(&r.to_repr(), u8::from(recovery_id.is_y_odd()).into());

if R.is_none().into() {
Expand Down
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