diff --git a/crates/claims/crates/cose/src/lib.rs b/crates/claims/crates/cose/src/lib.rs
index bb3803883..da6cf3fe4 100644
--- a/crates/claims/crates/cose/src/lib.rs
+++ b/crates/claims/crates/cose/src/lib.rs
@@ -152,6 +152,12 @@ pub trait CosePayload {
     }
 }
 
+impl CosePayload for [u8] {
+    fn payload_bytes(&self) -> Cow<[u8]> {
+        Cow::Borrowed(self)
+    }
+}
+
 pub const TYP_LABEL: Label = Label::Int(16);
 
 /// COSE payload type.
diff --git a/crates/claims/crates/cose/src/signature.rs b/crates/claims/crates/cose/src/signature.rs
index 9fc01d400..fc90f0e26 100644
--- a/crates/claims/crates/cose/src/signature.rs
+++ b/crates/claims/crates/cose/src/signature.rs
@@ -90,3 +90,68 @@ impl<'a, T: CoseSigner> CoseSigner for &'a T {
         T::sign(*self, payload, additional_data, tagged).await
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use crate::{key::CoseKeyGenerate, CosePayload, DecodedCoseSign1};
+    use coset::CoseKey;
+    use ssi_claims_core::VerificationParameters;
+
+    async fn sign_with(key: &CoseKey, tagged: bool) {
+        let bytes = b"PAYLOAD".sign(key, tagged).await.unwrap();
+        let decoded: DecodedCoseSign1 = bytes.decode(tagged).unwrap();
+
+        assert_eq!(decoded.signing_bytes.payload.as_bytes(), b"PAYLOAD");
+
+        let params = VerificationParameters::from_resolver(key);
+        assert_eq!(decoded.verify(params).await.unwrap(), Ok(()));
+    }
+
+    #[cfg(feature = "ed25519")]
+    #[async_std::test]
+    async fn sign_ed25519() {
+        sign_with(&CoseKey::generate_ed25519(), false).await
+    }
+
+    #[cfg(feature = "ed25519")]
+    #[async_std::test]
+    async fn sign_ed25519_tagged() {
+        sign_with(&CoseKey::generate_ed25519(), true).await
+    }
+
+    #[cfg(feature = "secp256k1")]
+    #[async_std::test]
+    async fn sign_secp256k1() {
+        sign_with(&CoseKey::generate_secp256k1(), false).await
+    }
+
+    #[cfg(feature = "secp256k1")]
+    #[async_std::test]
+    async fn sign_secp256k1_tagged() {
+        sign_with(&CoseKey::generate_secp256k1(), true).await
+    }
+
+    #[cfg(feature = "secp256r1")]
+    #[async_std::test]
+    async fn sign_p256() {
+        sign_with(&CoseKey::generate_p256(), false).await
+    }
+
+    #[cfg(feature = "secp256r1")]
+    #[async_std::test]
+    async fn sign_p256_tagged() {
+        sign_with(&CoseKey::generate_p256(), true).await
+    }
+
+    #[cfg(feature = "secp384r1")]
+    #[async_std::test]
+    async fn sign_p384() {
+        sign_with(&CoseKey::generate_p384(), false).await
+    }
+
+    #[cfg(feature = "secp384r1")]
+    #[async_std::test]
+    async fn sign_p384_tagged() {
+        sign_with(&CoseKey::generate_p384(), true).await
+    }
+}
diff --git a/crates/claims/crates/cose/src/verification.rs b/crates/claims/crates/cose/src/verification.rs
index 95eaf6c16..b627394ca 100644
--- a/crates/claims/crates/cose/src/verification.rs
+++ b/crates/claims/crates/cose/src/verification.rs
@@ -46,6 +46,8 @@ pub trait ValidateCoseHeader<P> {
     }
 }
 
+impl<P> ValidateCoseHeader<P> for () {}
+
 impl<E, T> ValidateClaims<E, CoseSignatureBytes> for UnsignedCoseSign1<T>
 where
     T: ValidateClaims<E, CoseSignatureBytes> + ValidateCoseHeader<E>,
diff --git a/crates/crypto/src/signature.rs b/crates/crypto/src/signature.rs
index 3bf3a4200..a6424786b 100644
--- a/crates/crypto/src/signature.rs
+++ b/crates/crypto/src/signature.rs
@@ -13,6 +13,28 @@ impl AlgorithmInstance {
     #[allow(unused)]
     pub fn sign(&self, key: &SecretKey, signing_bytes: &[u8]) -> Result<Vec<u8>, SignatureError> {
         match self {
+            #[cfg(feature = "ed25519")]
+            Self::EdDSA => match key {
+                SecretKey::Ed25519(key) => {
+                    use ed25519_dalek::Signer;
+                    Ok(key.sign(signing_bytes).to_bytes().to_vec())
+                }
+                #[allow(unreachable_patterns)]
+                _ => Err(SignatureError::IncompatibleKey),
+            },
+            #[cfg(feature = "secp256k1")]
+            Self::ES256K => {
+                match key {
+                    SecretKey::Secp256k1(key) => {
+                        use k256::ecdsa::{signature::Signer, Signature};
+                        let signing_key = k256::ecdsa::SigningKey::from(key);
+                        let signature: Signature = signing_key.try_sign(signing_bytes).unwrap(); // Uses SHA-256 by default.
+                        Ok(signature.to_bytes().to_vec())
+                    }
+                    #[allow(unreachable_patterns)]
+                    _ => Err(SignatureError::IncompatibleKey),
+                }
+            }
             #[cfg(feature = "secp256r1")]
             Self::ES256 => {
                 match key {
diff --git a/crates/crypto/src/verification.rs b/crates/crypto/src/verification.rs
index 165ce6b5b..614dc42d4 100644
--- a/crates/crypto/src/verification.rs
+++ b/crates/crypto/src/verification.rs
@@ -21,6 +21,30 @@ impl AlgorithmInstance {
         signature_bytes: &[u8],
     ) -> Result<bool, VerificationError> {
         match self {
+            #[cfg(feature = "ed25519")]
+            Self::EdDSA => match key {
+                PublicKey::Ed25519(key) => {
+                    use ed25519_dalek::Verifier;
+                    let signature: ed25519_dalek::Signature = signature_bytes
+                        .try_into()
+                        .map_err(|_| VerificationError::InvalidSignature)?;
+                    Ok(key.verify(signing_bytes, &signature).is_ok())
+                }
+                #[allow(unreachable_patterns)]
+                _ => Err(VerificationError::IncompatibleKey),
+            },
+            #[cfg(feature = "secp256k1")]
+            Self::ES256K => match key {
+                PublicKey::Secp256k1(key) => {
+                    use k256::ecdsa::signature::Verifier;
+                    let verifying_key = k256::ecdsa::VerifyingKey::from(key);
+                    let sig = k256::ecdsa::Signature::try_from(signature_bytes)
+                        .map_err(|_| VerificationError::InvalidSignature)?;
+                    Ok(verifying_key.verify(signing_bytes, &sig).is_ok())
+                }
+                #[allow(unreachable_patterns)]
+                _ => Err(VerificationError::IncompatibleKey),
+            },
             #[cfg(feature = "secp256r1")]
             Self::ES256 => match key {
                 PublicKey::P256(key) => {