diff --git a/registry/repository.go b/registry/repository.go
index 3a8cc70f..e25616e8 100644
--- a/registry/repository.go
+++ b/registry/repository.go
@@ -199,7 +199,7 @@ func (c *repositoryClient) uploadSignatureManifest(ctx context.Context, subject,
 		Subject:             &subject,
 		ManifestAnnotations: annotations,
 		Layers:              []ocispec.Descriptor{blobDesc},
-		ConfigDescriptor:    configDesc,
+		ConfigDescriptor:    &configDesc,
 	}
 
 	return oras.PackManifest(ctx, c.GraphTarget, oras.PackManifestVersion1_1_RC4, "", opts)
@@ -207,27 +207,28 @@ func (c *repositoryClient) uploadSignatureManifest(ctx context.Context, subject,
 
 // pushNotationManifestConfig pushes an empty notation manifest config, if it
 // doesn't exist.
-func pushNotationManifestConfig(ctx context.Context, pusher content.Pusher) (*ocispec.Descriptor, error) {
+func pushNotationManifestConfig(ctx context.Context, pusher content.Storage) (ocispec.Descriptor, error) {
 	// generate a empty config descriptor for notation manifest
-	configContent := []byte("{}")
-	desc := content.NewDescriptorFromBytes(ArtifactTypeNotation, configContent)
+	desc := ocispec.Descriptor{
+		MediaType: ArtifactTypeNotation,
+		Digest:    ocispec.DescriptorEmptyJSON.Digest,
+		Size:      ocispec.DescriptorEmptyJSON.Size,
+	}
 
 	// check if the config exists
-	if ros, ok := pusher.(content.ReadOnlyStorage); ok {
-		exists, err := ros.Exists(ctx, desc)
-		if err != nil {
-			return nil, fmt.Errorf("failed to check existence: %s: %s: %w", desc.Digest.String(), desc.MediaType, err)
-		}
-		if exists {
-			return &desc, nil
-		}
+	exists, err := pusher.Exists(ctx, desc)
+	if err != nil {
+		return ocispec.Descriptor{}, fmt.Errorf("failed to check existence: %s: %s: %w", desc.Digest.String(), desc.MediaType, err)
+	}
+	if exists {
+		return desc, nil
 	}
 
 	// push the config
-	if err := pusher.Push(ctx, desc, bytes.NewReader(configContent)); err != nil && !errors.Is(err, errdef.ErrAlreadyExists) {
-		return nil, fmt.Errorf("failed to push: %s: %s: %w", desc.Digest.String(), desc.MediaType, err)
+	if err := pusher.Push(ctx, desc, bytes.NewReader(ocispec.DescriptorEmptyJSON.Data)); err != nil && !errors.Is(err, errdef.ErrAlreadyExists) {
+		return ocispec.Descriptor{}, fmt.Errorf("failed to push: %s: %s: %w", desc.Digest.String(), desc.MediaType, err)
 	}
-	return &desc, nil
+	return desc, nil
 }
 
 // signatureReferrers returns referrer nodes of desc in target filtered by