Revert "ecdsa: use blanket impl from signature 3 (#945)" (#955)

This reverts commit 8e6bb26c26.

ecdsa/CHANGELOG.md

@@ -4,14 +4,6 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
-## 0.17.0 (UNRELEASED)
-
-### Changed
-- `DigestPrimitive` was moved off of hazmat ([#945])
-- `DigestPrimitive` has been renamed `DigestAlgorithm` ([#945])
-
-[#945]: https://github.com/RustCrypto/signatures/pull/945
-
 ## 0.16.9 (2023-11-16)
 ### Changed
 - Loosen `signature` bound to `2.0, <2.3` ([#756])

ecdsa/Cargo.toml

@@ -45,7 +45,6 @@ digest = ["dep:digest", "elliptic-curve/digest", "signature/digest"]
 hazmat = []
 pkcs8 = ["digest", "elliptic-curve/pkcs8", "der"]
 pem = ["elliptic-curve/pem", "pkcs8"]
-rfc6979 = ["arithmetic", "digest", "dep:rfc6979"]
 serde = ["elliptic-curve/serde", "pkcs8", "serdect"]
 signing = ["arithmetic", "digest", "hazmat", "rfc6979"]
 verifying = ["arithmetic", "digest", "hazmat"]

ecdsa/src/der.rs

@@ -382,10 +382,10 @@ fn find_scalar_range(outer: &[u8], inner: &[u8]) -> Result<Range<usize>> {
     Ok(Range { start, end })
 }
 
-#[cfg(feature = "digest")]
+#[cfg(all(feature = "digest", feature = "hazmat"))]
 impl<C> signature::PrehashSignature for Signature<C>
 where
-    C: EcdsaCurve + crate::DigestAlgorithm,
+    C: EcdsaCurve + crate::hazmat::DigestPrimitive,
     MaxSize<C>: ArraySize,
     <FieldBytesSize<C> as Add>::Output: Add<MaxOverhead> + ArraySize,
 {

ecdsa/src/hazmat.rs

@@ -27,21 +27,46 @@ use {
     },
 };
 
-#[cfg(feature = "rfc6979")]
+#[cfg(feature = "digest")]
 use {
-    elliptic_curve::FieldBytesEncoding,
-    signature::digest::{Digest, FixedOutput, FixedOutputReset, core_api::BlockSizeUser},
+    elliptic_curve::FieldBytesSize,
+    signature::{
+        PrehashSignature,
+        digest::{Digest, FixedOutput, FixedOutputReset, core_api::BlockSizeUser},
+    },
 };
 
-#[cfg(any(feature = "arithmetic", feature = "rfc6979"))]
+#[cfg(feature = "rfc6979")]
+use elliptic_curve::FieldBytesEncoding;
+
+#[cfg(any(feature = "arithmetic", feature = "digest"))]
 use crate::{Signature, elliptic_curve::array::ArraySize};
 
+/// Bind a preferred [`Digest`] algorithm to an elliptic curve type.
+///
+/// Generally there is a preferred variety of the SHA-2 family used with ECDSA
+/// for a particular elliptic curve.
+///
+/// This trait can be used to specify it, and with it receive a blanket impl of
+/// [`PrehashSignature`], used by [`signature_derive`][1]) for the [`Signature`]
+/// type for a particular elliptic curve.
+///
+/// [1]: https://github.com/RustCrypto/traits/tree/master/signature/derive
 #[cfg(feature = "digest")]
-#[deprecated(
-    since = "0.17.0",
-    note = "`DigestAlgorithm` is no longer in `hazmat`, please use `ecdsa::DigestAlgorithm` instead"
-)]
-pub use crate::DigestAlgorithm;
+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;
+}
+
+#[cfg(feature = "digest")]
+impl<C> PrehashSignature for Signature<C>
+where
+    C: DigestPrimitive,
+    <FieldBytesSize<C> as core::ops::Add>::Output: ArraySize,
+{
+    type Digest = C::Digest;
+}
 
 /// Partial implementation of the `bits2int` function as defined in
 /// [RFC6979 § 2.3.2] as well as [SEC1] § 2.3.8.

ecdsa/src/lib.rs

@@ -102,13 +102,9 @@ use {
 };
 
 #[cfg(feature = "digest")]
-use {
-    digest::{
-        Digest, FixedOutput, FixedOutputReset,
-        const_oid::{AssociatedOid, ObjectIdentifier},
-        core_api::BlockSizeUser,
-    },
-    signature::PrehashSignature,
+use digest::{
+    Digest,
+    const_oid::{AssociatedOid, ObjectIdentifier},
 };
 
 #[cfg(feature = "pkcs8")]
@@ -468,15 +464,15 @@ where
 ///
 /// To support non-default digest algorithms, use the [`SignatureWithOid`]
 /// type instead.
-#[cfg(feature = "digest")]
+#[cfg(all(feature = "digest", feature = "hazmat"))]
 impl<C> AssociatedOid for Signature<C>
 where
-    C: DigestAlgorithm,
+    C: hazmat::DigestPrimitive,
     C::Digest: AssociatedOid,
 {
     const OID: ObjectIdentifier = match ecdsa_oid_for_digest(C::Digest::OID) {
         Some(oid) => oid,
-        None => panic!("no RFC5758 ECDSA OID defined for DigestAlgorithm::Digest"),
+        None => panic!("no RFC5758 ECDSA OID defined for DigestPrimitive::Digest"),
     };
 }
 
@@ -725,14 +721,14 @@ where
 }
 
 /// NOTE: this implementation assumes the default digest for the given elliptic
-/// curve as defined by [`DigestAlgorithm`].
+/// curve as defined by [`hazmat::DigestPrimitive`].
 ///
 /// When working with alternative digests, you will need to use e.g.
 /// [`SignatureWithOid::new_with_digest`].
-#[cfg(feature = "digest")]
+#[cfg(all(feature = "digest", feature = "hazmat"))]
 impl<C> SignatureEncoding for SignatureWithOid<C>
 where
-    C: DigestAlgorithm,
+    C: hazmat::DigestPrimitive,
     C::Digest: AssociatedOid,
     SignatureSize<C>: ArraySize,
 {
@@ -740,14 +736,14 @@ where
 }
 
 /// NOTE: this implementation assumes the default digest for the given elliptic
-/// curve as defined by [`DigestAlgorithm`].
+/// curve as defined by [`hazmat::DigestPrimitive`].
 ///
 /// When working with alternative digests, you will need to use e.g.
 /// [`SignatureWithOid::new_with_digest`].
-#[cfg(feature = "digest")]
+#[cfg(all(feature = "digest", feature = "hazmat"))]
 impl<C> TryFrom<&[u8]> for SignatureWithOid<C>
 where
-    C: DigestAlgorithm,
+    C: hazmat::DigestPrimitive,
     C::Digest: AssociatedOid,
     SignatureSize<C>: ArraySize,
 {
@@ -782,29 +778,3 @@ const fn ecdsa_oid_for_digest(digest_oid: ObjectIdentifier) -> Option<ObjectIden
         _ => None,
     }
 }
-
-/// Bind a preferred [`Digest`] algorithm to an elliptic curve type.
-///
-/// Generally there is a preferred variety of the SHA-2 family used with ECDSA
-/// for a particular elliptic curve.
-///
-/// This trait can be used to specify it, and with it receive a blanket impl of
-/// [`PrehashSignature`], used by [`signature_derive`][1]) for the [`Signature`]
-/// type for a particular elliptic curve.
-///
-/// [1]: https://github.com/RustCrypto/traits/tree/master/signature/derive
-#[cfg(feature = "digest")]
-pub trait DigestAlgorithm: 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;
-}
-
-#[cfg(feature = "digest")]
-impl<C> PrehashSignature for Signature<C>
-where
-    C: DigestAlgorithm,
-    <FieldBytesSize<C> as Add>::Output: ArraySize,
-{
-    type Digest = C::Digest;
-}

ecdsa/src/recovery.rs

@@ -7,7 +7,7 @@ use {
     crate::{SigningKey, hazmat::sign_prehashed_rfc6979},
     elliptic_curve::{FieldBytes, subtle::CtOption},
     signature::{
-        DigestSigner, RandomizedDigestSigner,
+        DigestSigner, RandomizedDigestSigner, Signer,
         digest::FixedOutput,
         hazmat::{PrehashSigner, RandomizedPrehashSigner},
         rand_core::TryCryptoRng,
@@ -28,7 +28,10 @@ use {
 
 #[cfg(any(feature = "signing", feature = "verifying"))]
 use {
-    crate::{DigestAlgorithm, EcdsaCurve, Signature, SignatureSize, hazmat::bits2field},
+    crate::{
+        EcdsaCurve, Signature, SignatureSize,
+        hazmat::{DigestPrimitive, bits2field},
+    },
     elliptic_curve::{CurveArithmetic, Scalar, array::ArraySize, ops::Invert},
     signature::digest::Digest,
 };
@@ -97,7 +100,7 @@ impl RecoveryId {
         signature: &Signature<C>,
     ) -> Result<Self>
     where
-        C: EcdsaCurve + CurveArithmetic + DigestAlgorithm,
+        C: EcdsaCurve + CurveArithmetic + DigestPrimitive,
         AffinePoint<C>: DecompressPoint<C> + FromEncodedPoint<C> + ToEncodedPoint<C>,
         FieldBytesSize<C>: sec1::ModulusSize,
         SignatureSize<C>: ArraySize,
@@ -176,7 +179,7 @@ impl From<RecoveryId> for u8 {
 #[cfg(feature = "signing")]
 impl<C> SigningKey<C>
 where
-    C: EcdsaCurve + CurveArithmetic + DigestAlgorithm,
+    C: EcdsaCurve + CurveArithmetic + DigestPrimitive,
     Scalar<C>: Invert<Output = CtOption<Scalar<C>>>,
     SignatureSize<C>: ArraySize,
 {
@@ -225,7 +228,7 @@ where
 #[cfg(feature = "signing")]
 impl<C, D> DigestSigner<D, (Signature<C>, RecoveryId)> for SigningKey<C>
 where
-    C: EcdsaCurve + CurveArithmetic + DigestAlgorithm,
+    C: EcdsaCurve + CurveArithmetic + DigestPrimitive,
     D: Digest,
     Scalar<C>: Invert<Output = CtOption<Scalar<C>>>,
     SignatureSize<C>: ArraySize,
@@ -238,7 +241,7 @@ where
 #[cfg(feature = "signing")]
 impl<C> RandomizedPrehashSigner<(Signature<C>, RecoveryId)> for SigningKey<C>
 where
-    C: EcdsaCurve + CurveArithmetic + DigestAlgorithm,
+    C: EcdsaCurve + CurveArithmetic + DigestPrimitive,
     Scalar<C>: Invert<Output = CtOption<Scalar<C>>>,
     SignatureSize<C>: ArraySize,
 {
@@ -254,7 +257,7 @@ where
 #[cfg(feature = "signing")]
 impl<C, D> RandomizedDigestSigner<D, (Signature<C>, RecoveryId)> for SigningKey<C>
 where
-    C: EcdsaCurve + CurveArithmetic + DigestAlgorithm,
+    C: EcdsaCurve + CurveArithmetic + DigestPrimitive,
     D: Digest + FixedOutput,
     Scalar<C>: Invert<Output = CtOption<Scalar<C>>>,
     SignatureSize<C>: ArraySize,
@@ -271,7 +274,7 @@ where
 #[cfg(feature = "signing")]
 impl<C> PrehashSigner<(Signature<C>, RecoveryId)> for SigningKey<C>
 where
-    C: EcdsaCurve + CurveArithmetic + DigestAlgorithm,
+    C: EcdsaCurve + CurveArithmetic + DigestPrimitive,
     Scalar<C>: Invert<Output = CtOption<Scalar<C>>>,
     SignatureSize<C>: ArraySize,
 {
@@ -280,6 +283,18 @@ where
     }
 }
 
+#[cfg(feature = "signing")]
+impl<C> Signer<(Signature<C>, RecoveryId)> for SigningKey<C>
+where
+    C: EcdsaCurve + CurveArithmetic + DigestPrimitive,
+    Scalar<C>: Invert<Output = CtOption<Scalar<C>>>,
+    SignatureSize<C>: ArraySize,
+{
+    fn try_sign(&self, msg: &[u8]) -> Result<(Signature<C>, RecoveryId)> {
+        self.sign_recoverable(msg)
+    }
+}
+
 #[cfg(feature = "verifying")]
 impl<C> VerifyingKey<C>
 where
@@ -291,14 +306,14 @@ where
     /// Recover a [`VerifyingKey`] from the given message, signature, and
     /// [`RecoveryId`].
     ///
-    /// The message is first hashed using this curve's [`DigestAlgorithm`].
+    /// The message is first hashed using this curve's [`DigestPrimitive`].
     pub fn recover_from_msg(
         msg: &[u8],
         signature: &Signature<C>,
         recovery_id: RecoveryId,
     ) -> Result<Self>
     where
-        C: DigestAlgorithm,
+        C: DigestPrimitive,
     {
         Self::recover_from_digest(C::Digest::new_with_prefix(msg), signature, recovery_id)
     }

ecdsa/src/signing.rs

@@ -1,9 +1,8 @@
 //! ECDSA signing: producing signatures using a [`SigningKey`].
 
 use crate::{
-    DigestAlgorithm, EcdsaCurve, Error, Result, Signature, SignatureSize, SignatureWithOid,
-    ecdsa_oid_for_digest,
-    hazmat::{bits2field, sign_prehashed_rfc6979},
+    EcdsaCurve, Error, Result, Signature, SignatureSize, SignatureWithOid, ecdsa_oid_for_digest,
+    hazmat::{DigestPrimitive, bits2field, sign_prehashed_rfc6979},
 };
 use core::fmt::{self, Debug};
 use digest::{Digest, FixedOutput, const_oid::AssociatedOid};
@@ -16,7 +15,7 @@ use elliptic_curve::{
     zeroize::{Zeroize, ZeroizeOnDrop},
 };
 use signature::{
-    DigestSigner, RandomizedDigestSigner, Signer,
+    DigestSigner, RandomizedDigestSigner, RandomizedSigner, Signer,
     hazmat::{PrehashSigner, RandomizedPrehashSigner},
     rand_core::{CryptoRng, TryCryptoRng},
 };
@@ -140,7 +139,7 @@ where
 /// [RFC6979 § 3.2]: https://tools.ietf.org/html/rfc6979#section-3
 impl<C, D> DigestSigner<D, Signature<C>> for SigningKey<C>
 where
-    C: EcdsaCurve + CurveArithmetic + DigestAlgorithm,
+    C: EcdsaCurve + CurveArithmetic + DigestPrimitive,
     D: Digest + FixedOutput,
     Scalar<C>: Invert<Output = CtOption<Scalar<C>>>,
     SignatureSize<C>: ArraySize,
@@ -156,7 +155,7 @@ where
 /// [RFC6979 § 3.2]: https://tools.ietf.org/html/rfc6979#section-3
 impl<C> PrehashSigner<Signature<C>> for SigningKey<C>
 where
-    C: EcdsaCurve + CurveArithmetic + DigestAlgorithm,
+    C: EcdsaCurve + CurveArithmetic + DigestPrimitive,
     Scalar<C>: Invert<Output = CtOption<Scalar<C>>>,
     SignatureSize<C>: ArraySize,
 {
@@ -166,9 +165,24 @@ where
     }
 }
 
+/// Sign message using a deterministic ephemeral scalar (`k`)
+/// computed using the algorithm described in [RFC6979 § 3.2].
+///
+/// [RFC6979 § 3.2]: https://tools.ietf.org/html/rfc6979#section-3
+impl<C> Signer<Signature<C>> for SigningKey<C>
+where
+    C: EcdsaCurve + CurveArithmetic + DigestPrimitive,
+    Scalar<C>: Invert<Output = CtOption<Scalar<C>>>,
+    SignatureSize<C>: ArraySize,
+{
+    fn try_sign(&self, msg: &[u8]) -> Result<Signature<C>> {
+        self.try_sign_digest(C::Digest::new_with_prefix(msg))
+    }
+}
+
 impl<C, D> RandomizedDigestSigner<D, Signature<C>> for SigningKey<C>
 where
-    C: EcdsaCurve + CurveArithmetic + DigestAlgorithm,
+    C: EcdsaCurve + CurveArithmetic + DigestPrimitive,
     D: Digest + FixedOutput,
     Scalar<C>: Invert<Output = CtOption<Scalar<C>>>,
     SignatureSize<C>: ArraySize,
@@ -184,7 +198,7 @@ where
 
 impl<C> RandomizedPrehashSigner<Signature<C>> for SigningKey<C>
 where
-    C: EcdsaCurve + CurveArithmetic + DigestAlgorithm,
+    C: EcdsaCurve + CurveArithmetic + DigestPrimitive,
     Scalar<C>: Invert<Output = CtOption<Scalar<C>>>,
     SignatureSize<C>: ArraySize,
 {
@@ -208,9 +222,25 @@ where
     }
 }
 
+impl<C> RandomizedSigner<Signature<C>> for SigningKey<C>
+where
+    Self: RandomizedDigestSigner<C::Digest, Signature<C>>,
+    C: EcdsaCurve + CurveArithmetic + DigestPrimitive,
+    Scalar<C>: Invert<Output = CtOption<Scalar<C>>>,
+    SignatureSize<C>: ArraySize,
+{
+    fn try_sign_with_rng<R: TryCryptoRng + ?Sized>(
+        &self,
+        rng: &mut R,
+        msg: &[u8],
+    ) -> Result<Signature<C>> {
+        self.try_sign_digest_with_rng(rng, C::Digest::new_with_prefix(msg))
+    }
+}
+
 impl<C, D> DigestSigner<D, SignatureWithOid<C>> for SigningKey<C>
 where
-    C: EcdsaCurve + CurveArithmetic + DigestAlgorithm,
+    C: EcdsaCurve + CurveArithmetic + DigestPrimitive,
     D: AssociatedOid + Digest + FixedOutput,
     Scalar<C>: Invert<Output = CtOption<Scalar<C>>>,
     SignatureSize<C>: ArraySize,
@@ -224,7 +254,7 @@ where
 
 impl<C> Signer<SignatureWithOid<C>> for SigningKey<C>
 where
-    C: EcdsaCurve + CurveArithmetic + DigestAlgorithm,
+    C: EcdsaCurve + CurveArithmetic + DigestPrimitive,
     C::Digest: AssociatedOid,
     Scalar<C>: Invert<Output = CtOption<Scalar<C>>>,
     SignatureSize<C>: ArraySize,
@@ -237,7 +267,7 @@ where
 #[cfg(feature = "der")]
 impl<C> PrehashSigner<der::Signature<C>> for SigningKey<C>
 where
-    C: EcdsaCurve + CurveArithmetic + DigestAlgorithm,
+    C: EcdsaCurve + CurveArithmetic + DigestPrimitive,
     Scalar<C>: Invert<Output = CtOption<Scalar<C>>>,
     SignatureSize<C>: ArraySize,
     der::MaxSize<C>: ArraySize,
@@ -248,10 +278,44 @@ where
     }
 }
 
+#[cfg(feature = "der")]
+impl<C> Signer<der::Signature<C>> for SigningKey<C>
+where
+    C: EcdsaCurve + CurveArithmetic + DigestPrimitive,
+    Scalar<C>: Invert<Output = CtOption<Scalar<C>>>,
+    SignatureSize<C>: ArraySize,
+    der::MaxSize<C>: ArraySize,
+    <FieldBytesSize<C> as Add>::Output: Add<der::MaxOverhead> + ArraySize,
+{
+    fn try_sign(&self, msg: &[u8]) -> Result<der::Signature<C>> {
+        Signer::<Signature<C>>::try_sign(self, msg).map(Into::into)
+    }
+}
+
+#[cfg(feature = "der")]
+impl<C, D> RandomizedDigestSigner<D, der::Signature<C>> for SigningKey<C>
+where
+    C: EcdsaCurve + CurveArithmetic + DigestPrimitive,
+    D: Digest + FixedOutput,
+    Scalar<C>: Invert<Output = CtOption<Scalar<C>>>,
+    SignatureSize<C>: ArraySize,
+    der::MaxSize<C>: ArraySize,
+    <FieldBytesSize<C> as Add>::Output: Add<der::MaxOverhead> + ArraySize,
+{
+    fn try_sign_digest_with_rng<R: TryCryptoRng + ?Sized>(
+        &self,
+        rng: &mut R,
+        msg_digest: D,
+    ) -> Result<der::Signature<C>> {
+        RandomizedDigestSigner::<D, Signature<C>>::try_sign_digest_with_rng(self, rng, msg_digest)
+            .map(Into::into)
+    }
+}
+
 #[cfg(feature = "der")]
 impl<C> RandomizedPrehashSigner<der::Signature<C>> for SigningKey<C>
 where
-    C: EcdsaCurve + CurveArithmetic + DigestAlgorithm,
+    C: EcdsaCurve + CurveArithmetic + DigestPrimitive,
     Scalar<C>: Invert<Output = CtOption<Scalar<C>>>,
     SignatureSize<C>: ArraySize,
     der::MaxSize<C>: ArraySize,
@@ -270,7 +334,7 @@ where
 #[cfg(feature = "der")]
 impl<D, C> DigestSigner<D, der::Signature<C>> for SigningKey<C>
 where
-    C: EcdsaCurve + CurveArithmetic + DigestAlgorithm,
+    C: EcdsaCurve + CurveArithmetic + DigestPrimitive,
     D: Digest + FixedOutput,
     Scalar<C>: Invert<Output = CtOption<Scalar<C>>>,
     SignatureSize<C>: ArraySize,
@@ -282,26 +346,6 @@ where
     }
 }
 
-#[cfg(feature = "der")]
-impl<C, D> RandomizedDigestSigner<D, der::Signature<C>> for SigningKey<C>
-where
-    C: EcdsaCurve + CurveArithmetic + DigestAlgorithm,
-    D: Digest + FixedOutput,
-    Scalar<C>: Invert<Output = CtOption<Scalar<C>>>,
-    SignatureSize<C>: ArraySize,
-    der::MaxSize<C>: ArraySize,
-    <FieldBytesSize<C> as Add>::Output: Add<der::MaxOverhead> + ArraySize,
-{
-    fn try_sign_digest_with_rng<R: TryCryptoRng + ?Sized>(
-        &self,
-        rng: &mut R,
-        msg_digest: D,
-    ) -> Result<der::Signature<C>> {
-        RandomizedDigestSigner::<D, Signature<C>>::try_sign_digest_with_rng(self, rng, msg_digest)
-            .map(Into::into)
-    }
-}
-
 //
 // Other trait impls
 //

ecdsa/src/verifying.rs

@@ -2,7 +2,7 @@
 
 use crate::{
     EcdsaCurve, Error, Result, Signature, SignatureSize,
-    hazmat::{self, bits2field},
+    hazmat::{self, DigestPrimitive, bits2field},
 };
 use core::{cmp::Ordering, fmt::Debug};
 use elliptic_curve::{
@@ -13,7 +13,7 @@ use elliptic_curve::{
     sec1::{self, CompressedPoint, EncodedPoint, FromEncodedPoint, ToEncodedPoint},
 };
 use signature::{
-    DigestVerifier,
+    DigestVerifier, Verifier,
     digest::{Digest, FixedOutput},
     hazmat::PrehashVerifier,
 };
@@ -42,11 +42,9 @@ use serdect::serde::{Deserialize, Serialize, de, ser};
 #[cfg(feature = "sha2")]
 use {
     crate::{
-        DigestAlgorithm, ECDSA_SHA224_OID, ECDSA_SHA256_OID, ECDSA_SHA384_OID, ECDSA_SHA512_OID,
-        SignatureWithOid,
+        ECDSA_SHA224_OID, ECDSA_SHA256_OID, ECDSA_SHA384_OID, ECDSA_SHA512_OID, SignatureWithOid,
     },
     sha2::{Sha224, Sha256, Sha384, Sha512},
-    signature::Verifier,
 };
 
 #[cfg(all(feature = "alloc", feature = "pkcs8"))]
@@ -174,10 +172,20 @@ where
     }
 }
 
+impl<C> Verifier<Signature<C>> for VerifyingKey<C>
+where
+    C: EcdsaCurve + CurveArithmetic + DigestPrimitive,
+    SignatureSize<C>: ArraySize,
+{
+    fn verify(&self, msg: &[u8], signature: &Signature<C>) -> Result<()> {
+        self.verify_digest(C::Digest::new_with_prefix(msg), signature)
+    }
+}
+
 #[cfg(feature = "sha2")]
 impl<C> Verifier<SignatureWithOid<C>> for VerifyingKey<C>
 where
-    C: EcdsaCurve + CurveArithmetic + DigestAlgorithm,
+    C: EcdsaCurve + CurveArithmetic + DigestPrimitive,
     SignatureSize<C>: ArraySize,
 {
     fn verify(&self, msg: &[u8], sig: &SignatureWithOid<C>) -> Result<()> {
@@ -220,6 +228,20 @@ where
     }
 }
 
+#[cfg(feature = "der")]
+impl<C> Verifier<der::Signature<C>> for VerifyingKey<C>
+where
+    C: EcdsaCurve + CurveArithmetic + DigestPrimitive,
+    SignatureSize<C>: ArraySize,
+    der::MaxSize<C>: ArraySize,
+    <FieldBytesSize<C> as Add>::Output: Add<der::MaxOverhead> + ArraySize,
+{
+    fn verify(&self, msg: &[u8], signature: &der::Signature<C>) -> Result<()> {
+        let signature = Signature::<C>::try_from(signature.clone())?;
+        Verifier::<Signature<C>>::verify(self, msg, &signature)
+    }
+}
+
 //
 // Other trait impls
 //