ecdsa: use EcdsaCurve in bounds (#792)

Replaces previous `PrimeCurve` bounds with the new `EcdsaCurve` trait
(which has a supertrait bound on `PrimeCurve`).

ecdsa/src/der.rs

@@ -3,7 +3,7 @@
 //!
 //! [RFC5912 Section 6]: https://www.rfc-editor.org/rfc/rfc5912#section-6
 
-use crate::{Error, Result};
+use crate::{EcdsaCurve, Error, Result};
 use core::{
     fmt::{self, Debug},
     ops::{Add, Range},
@@ -12,7 +12,7 @@ use der::{asn1::UintRef, Decode, Encode, FixedTag, Length, Reader, Tag, Writer};
 use elliptic_curve::{
     array::{typenum::Unsigned, Array, ArraySize},
     consts::U9,
-    FieldBytesSize, PrimeCurve,
+    FieldBytesSize,
 };
 
 #[cfg(feature = "alloc")]
@@ -59,7 +59,7 @@ type SignatureBytes<C> = Array<u8, MaxSize<C>>;
 /// [RFC5912 Section 6]: https://www.rfc-editor.org/rfc/rfc5912#section-6
 pub struct Signature<C>
 where
-    C: PrimeCurve,
+    C: EcdsaCurve,
     MaxSize<C>: ArraySize,
     <FieldBytesSize<C> as Add>::Output: Add<MaxOverhead> + ArraySize,
 {
@@ -76,7 +76,7 @@ where
 #[allow(clippy::len_without_is_empty)]
 impl<C> Signature<C>
 where
-    C: PrimeCurve,
+    C: EcdsaCurve,
     MaxSize<C>: ArraySize,
     <FieldBytesSize<C> as Add>::Output: Add<MaxOverhead> + ArraySize,
 {
@@ -156,7 +156,7 @@ where
 
 impl<C> AsRef<[u8]> for Signature<C>
 where
-    C: PrimeCurve,
+    C: EcdsaCurve,
     MaxSize<C>: ArraySize,
     <FieldBytesSize<C> as Add>::Output: Add<MaxOverhead> + ArraySize,
 {
@@ -167,7 +167,7 @@ where
 
 impl<C> Clone for Signature<C>
 where
-    C: PrimeCurve,
+    C: EcdsaCurve,
     MaxSize<C>: ArraySize,
     <FieldBytesSize<C> as Add>::Output: Add<MaxOverhead> + ArraySize,
 {
@@ -182,7 +182,7 @@ where
 
 impl<C> Debug for Signature<C>
 where
-    C: PrimeCurve,
+    C: EcdsaCurve,
     MaxSize<C>: ArraySize,
     <FieldBytesSize<C> as Add>::Output: Add<MaxOverhead> + ArraySize,
 {
@@ -199,7 +199,7 @@ where
 
 impl<'a, C> Decode<'a> for Signature<C>
 where
-    C: PrimeCurve,
+    C: EcdsaCurve,
     MaxSize<C>: ArraySize,
     <FieldBytesSize<C> as Add>::Output: Add<MaxOverhead> + ArraySize,
 {
@@ -220,7 +220,7 @@ where
 
 impl<C> Encode for Signature<C>
 where
-    C: PrimeCurve,
+    C: EcdsaCurve,
     MaxSize<C>: ArraySize,
     <FieldBytesSize<C> as Add>::Output: Add<MaxOverhead> + ArraySize,
 {
@@ -235,7 +235,7 @@ where
 
 impl<C> FixedTag for Signature<C>
 where
-    C: PrimeCurve,
+    C: EcdsaCurve,
     MaxSize<C>: ArraySize,
     <FieldBytesSize<C> as Add>::Output: Add<MaxOverhead> + ArraySize,
 {
@@ -244,7 +244,7 @@ where
 
 impl<C> From<crate::Signature<C>> for Signature<C>
 where
-    C: PrimeCurve,
+    C: EcdsaCurve,
     MaxSize<C>: ArraySize,
     <FieldBytesSize<C> as Add>::Output: Add<MaxOverhead> + ArraySize,
 {
@@ -255,7 +255,7 @@ where
 
 impl<C> TryFrom<&[u8]> for Signature<C>
 where
-    C: PrimeCurve,
+    C: EcdsaCurve,
     MaxSize<C>: ArraySize,
     <FieldBytesSize<C> as Add>::Output: Add<MaxOverhead> + ArraySize,
 {
@@ -268,7 +268,7 @@ where
 
 impl<C> TryFrom<Signature<C>> for crate::Signature<C>
 where
-    C: PrimeCurve,
+    C: EcdsaCurve,
     MaxSize<C>: ArraySize,
     <FieldBytesSize<C> as Add>::Output: Add<MaxOverhead> + ArraySize,
 {
@@ -287,7 +287,7 @@ where
 #[cfg(feature = "alloc")]
 impl<C> From<Signature<C>> for Box<[u8]>
 where
-    C: PrimeCurve,
+    C: EcdsaCurve,
     MaxSize<C>: ArraySize,
     <FieldBytesSize<C> as Add>::Output: Add<MaxOverhead> + ArraySize,
 {
@@ -299,7 +299,7 @@ where
 #[cfg(feature = "alloc")]
 impl<C> SignatureEncoding for Signature<C>
 where
-    C: PrimeCurve,
+    C: EcdsaCurve,
     MaxSize<C>: ArraySize,
     <FieldBytesSize<C> as Add>::Output: Add<MaxOverhead> + ArraySize,
 {
@@ -313,7 +313,7 @@ where
 #[cfg(feature = "alloc")]
 impl<C> SignatureBitStringEncoding for Signature<C>
 where
-    C: PrimeCurve,
+    C: EcdsaCurve,
     MaxSize<C>: ArraySize,
     <FieldBytesSize<C> as Add>::Output: Add<MaxOverhead> + ArraySize,
 {
@@ -325,7 +325,7 @@ where
 #[cfg(feature = "serde")]
 impl<C> Serialize for Signature<C>
 where
-    C: PrimeCurve,
+    C: EcdsaCurve,
     MaxSize<C>: ArraySize,
     <FieldBytesSize<C> as Add>::Output: Add<MaxOverhead> + ArraySize,
 {
@@ -340,7 +340,7 @@ where
 #[cfg(feature = "serde")]
 impl<'de, C> Deserialize<'de> for Signature<C>
 where
-    C: PrimeCurve,
+    C: EcdsaCurve,
     MaxSize<C>: ArraySize,
     <FieldBytesSize<C> as Add>::Output: Add<MaxOverhead> + ArraySize,
 {
@@ -383,7 +383,7 @@ fn find_scalar_range(outer: &[u8], inner: &[u8]) -> Result<Range<usize>> {
 #[cfg(all(feature = "digest", feature = "hazmat"))]
 impl<C> signature::PrehashSignature for Signature<C>
 where
-    C: PrimeCurve + crate::hazmat::DigestPrimitive,
+    C: EcdsaCurve + crate::hazmat::DigestPrimitive,
     MaxSize<C>: ArraySize,
     <FieldBytesSize<C> as Add>::Output: Add<MaxOverhead> + ArraySize,
 {

ecdsa/src/dev.rs

@@ -3,6 +3,13 @@
 // TODO(tarcieri): implement full set of tests from ECDSA2VS
 // <https://csrc.nist.gov/CSRC/media/Projects/Cryptographic-Algorithm-Validation-Program/documents/dss2/ecdsa2vs.pdf>
 
+use crate::EcdsaCurve;
+use elliptic_curve::dev::MockCurve;
+
+impl EcdsaCurve for MockCurve {
+    const NORMALIZE_S: bool = false;
+}
+
 /// ECDSA test vector
 pub struct TestVector {
     /// Private scalar

ecdsa/src/hazmat.rs

@@ -10,9 +10,9 @@
 //! Failure to use them correctly can lead to catastrophic failures including
 //! FULL PRIVATE KEY RECOVERY!
 
-use crate::{Error, Result};
+use crate::{EcdsaCurve, Error, Result};
 use core::cmp;
-use elliptic_curve::{array::typenum::Unsigned, FieldBytes, PrimeCurve};
+use elliptic_curve::{array::typenum::Unsigned, FieldBytes};
 
 #[cfg(feature = "arithmetic")]
 use {
@@ -56,7 +56,7 @@ pub trait SignPrimitive<C>:
     + Reduce<C::Uint, Bytes = FieldBytes<C>>
     + Sized
 where
-    C: PrimeCurve + CurveArithmetic<Scalar = Self>,
+    C: EcdsaCurve + CurveArithmetic<Scalar = Self>,
     SignatureSize<C>: ArraySize,
 {
     /// Try to sign the prehashed message.
@@ -128,7 +128,7 @@ where
 #[cfg(feature = "arithmetic")]
 pub trait VerifyPrimitive<C>: AffineCoordinates<FieldRepr = FieldBytes<C>> + Copy + Sized
 where
-    C: PrimeCurve + CurveArithmetic<AffinePoint = Self>,
+    C: EcdsaCurve + CurveArithmetic<AffinePoint = Self>,
     SignatureSize<C>: ArraySize,
 {
     /// Verify the prehashed message against the provided ECDSA signature.
@@ -163,7 +163,7 @@ where
 ///
 /// [1]: https://github.com/RustCrypto/traits/tree/master/signature/derive
 #[cfg(feature = "digest")]
-pub trait DigestPrimitive: PrimeCurve {
+pub trait DigestPrimitive: EcdsaCurve {
     /// Preferred digest to use when computing ECDSA signatures for this
     /// elliptic curve. This is typically a member of the SHA-2 family.
     type Digest: BlockSizeUser + Digest + FixedOutput + FixedOutputReset;
@@ -187,7 +187,7 @@ where
 ///
 /// [RFC6979 § 2.3.2]: https://datatracker.ietf.org/doc/html/rfc6979#section-2.3.2
 /// [SEC1]: https://www.secg.org/sec1-v2.pdf
-pub fn bits2field<C: PrimeCurve>(bits: &[u8]) -> Result<FieldBytes<C>> {
+pub fn bits2field<C: EcdsaCurve>(bits: &[u8]) -> Result<FieldBytes<C>> {
     // Minimum allowed bits size is half the field size
     if bits.len() < C::FieldBytesSize::USIZE / 2 {
         return Err(Error::new());
@@ -232,7 +232,7 @@ pub fn sign_prehashed<C, K>(
     z: &FieldBytes<C>,
 ) -> Result<(Signature<C>, RecoveryId)>
 where
-    C: PrimeCurve + CurveArithmetic,
+    C: EcdsaCurve + CurveArithmetic,
     K: AsRef<Scalar<C>> + Invert<Output = CtOption<Scalar<C>>>,
     SignatureSize<C>: ArraySize,
 {
@@ -278,7 +278,7 @@ pub fn verify_prehashed<C>(
     sig: &Signature<C>,
 ) -> Result<()>
 where
-    C: PrimeCurve + CurveArithmetic,
+    C: EcdsaCurve + CurveArithmetic,
     SignatureSize<C>: ArraySize,
 {
     let z = Scalar::<C>::reduce_bytes(z);
@@ -297,7 +297,7 @@ where
     }
 }
 
-#[cfg(test)]
+#[cfg(all(test, feature = "dev"))]
 mod tests {
     use super::bits2field;
     use elliptic_curve::dev::MockCurve;