diff --git a/jose/validate.go b/jose/validate.go
index f4047eea..6a904167 100644
--- a/jose/validate.go
+++ b/jose/validate.go
@@ -162,6 +162,12 @@ func validateSigJWK(jwk *JSONWebKey) error {
 			return nil
 		}
 		errctx = "kty 'OKP' and crv 'Ed25519'"
+	case OpaqueSigner:
+		for _, alg := range k.Algs() {
+			if jwk.Algorithm == string(alg) {
+				return nil
+			}
+		}
 	}
 
 	return errors.Errorf("alg '%s' is not compatible with %s", jwk.Algorithm, errctx)
diff --git a/jose/validate_test.go b/jose/validate_test.go
index 790d68ef..d09710be 100644
--- a/jose/validate_test.go
+++ b/jose/validate_test.go
@@ -13,6 +13,7 @@ import (
 
 	"github.com/pkg/errors"
 	"github.com/smallstep/assert"
+	"go.step.sm/crypto/keyutil"
 	"go.step.sm/crypto/pemutil"
 )
 
@@ -259,3 +260,62 @@ func TestValidateX5C(t *testing.T) {
 		})
 	}
 }
+
+func TestValidateJWK_sig(t *testing.T) {
+	mustSigner := func(kty, crv string, size int) crypto.Signer {
+		signer, err := keyutil.GenerateSigner(kty, crv, size)
+		if err != nil {
+			t.Fatal(err)
+		}
+		return signer
+	}
+
+	rsaKey := mustSigner("RSA", "", 2048)
+	p256Key := mustSigner("EC", "P-256", 0)
+	p384key := mustSigner("EC", "P-384", 0)
+	p521Key := mustSigner("EC", "P-521", 0)
+	edKey := mustSigner("OKP", "Ed25519", 0)
+
+	type args struct {
+		jwk *JSONWebKey
+	}
+	tests := []struct {
+		name    string
+		args    args
+		wantErr bool
+	}{
+		{"ok ES256", args{&JSONWebKey{Use: "sig", Algorithm: ES256, Key: p256Key}}, false},
+		{"ok ES384", args{&JSONWebKey{Use: "sig", Algorithm: ES384, Key: p384key}}, false},
+		{"ok ES512", args{&JSONWebKey{Use: "sig", Algorithm: ES512, Key: p521Key}}, false},
+		{"ok ES256 pub", args{&JSONWebKey{Use: "sig", Algorithm: ES256, Key: p256Key.Public()}}, false},
+		{"ok ES384 pub", args{&JSONWebKey{Use: "sig", Algorithm: ES384, Key: p384key.Public()}}, false},
+		{"ok ES512 pub", args{&JSONWebKey{Use: "sig", Algorithm: ES512, Key: p521Key.Public()}}, false},
+		{"ok RS256", args{&JSONWebKey{Use: "sig", Algorithm: RS256, Key: rsaKey}}, false},
+		{"ok RS384", args{&JSONWebKey{Use: "sig", Algorithm: RS384, Key: rsaKey.Public()}}, false},
+		{"ok RS512", args{&JSONWebKey{Use: "sig", Algorithm: RS512, Key: rsaKey}}, false},
+		{"ok PS256", args{&JSONWebKey{Use: "sig", Algorithm: PS256, Key: rsaKey.Public()}}, false},
+		{"ok PS384", args{&JSONWebKey{Use: "sig", Algorithm: PS384, Key: rsaKey}}, false},
+		{"ok PS512", args{&JSONWebKey{Use: "sig", Algorithm: PS512, Key: rsaKey.Public()}}, false},
+		{"ok EdDSA", args{&JSONWebKey{Use: "sig", Algorithm: EdDSA, Key: edKey}}, false},
+		{"ok EdDSA pub", args{&JSONWebKey{Use: "sig", Algorithm: EdDSA, Key: edKey.Public()}}, false},
+		{"ok HS256", args{&JSONWebKey{Use: "sig", Algorithm: HS256, Key: []byte("raw-key")}}, false},
+		{"ok HS384", args{&JSONWebKey{Use: "sig", Algorithm: HS384, Key: []byte("raw-key")}}, false},
+		{"ok HS512", args{&JSONWebKey{Use: "sig", Algorithm: HS512, Key: []byte("raw-key")}}, false},
+		{"ok OpaqueSigner", args{&JSONWebKey{Use: "sig", Algorithm: ES256, Key: NewOpaqueSigner(p256Key)}}, false},
+		{"fail alg empty", args{&JSONWebKey{Use: "sig", Key: p256Key}}, true},
+		{"fail ECDSA", args{&JSONWebKey{Use: "sig", Algorithm: ES384, Key: p256Key}}, true},
+		{"fail ECDSA pub", args{&JSONWebKey{Use: "sig", Algorithm: ES384, Key: p256Key.Public()}}, true},
+		{"fail RSA", args{&JSONWebKey{Use: "sig", Algorithm: ES256, Key: rsaKey}}, true},
+		{"fail Ed25519", args{&JSONWebKey{Use: "sig", Algorithm: ES256, Key: edKey}}, true},
+		{"fail bytes", args{&JSONWebKey{Use: "sig", Algorithm: ES256, Key: []byte("raw-key")}}, true},
+		{"fail OpaqueSigner", args{&JSONWebKey{Use: "sig", Algorithm: RS256, Key: p256Key}}, true},
+		{"fail unknown", args{&JSONWebKey{Use: "sig", Algorithm: HS256, Key: "raw-key"}}, true},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if err := ValidateJWK(tt.args.jwk); (err != nil) != tt.wantErr {
+				t.Errorf("ValidateJWK() error = %v, wantErr %v", err, tt.wantErr)
+			}
+		})
+	}
+}
diff --git a/kms/apiv1/options.go b/kms/apiv1/options.go
index f558b072..7013bb33 100644
--- a/kms/apiv1/options.go
+++ b/kms/apiv1/options.go
@@ -111,6 +111,46 @@ const (
 	TPMKMS Type = "tpmkms"
 )
 
+// TypeOf returns the type of of the given uri.
+func TypeOf(rawuri string) (Type, error) {
+	u, err := uri.Parse(rawuri)
+	if err != nil {
+		return DefaultKMS, err
+	}
+	t := Type(u.Scheme).normalize()
+	if err := t.Validate(); err != nil {
+		return DefaultKMS, err
+	}
+	return t, nil
+}
+
+func (t Type) normalize() Type {
+	return Type(strings.ToLower(string(t)))
+}
+
+// Validate return an error if the type is not a supported one.
+func (t Type) Validate() error {
+	typ := t.normalize()
+
+	switch typ {
+	case DefaultKMS, SoftKMS: // Go crypto based kms.
+		return nil
+	case CloudKMS, AmazonKMS, AzureKMS: // Cloud based kms.
+		return nil
+	case YubiKey, PKCS11, TPMKMS: // Hardware based kms.
+		return nil
+	case SSHAgentKMS, CAPIKMS: // Others
+		return nil
+	}
+
+	// Check other registered types
+	if _, ok := registry.Load(typ); ok {
+		return nil
+	}
+
+	return fmt.Errorf("unsupported kms type %s", t)
+}
+
 // Options are the KMS options. They represent the kms object in the ca.json.
 type Options struct {
 	// The type of the KMS to use.
@@ -155,18 +195,7 @@ func (o *Options) Validate() error {
 	if o == nil {
 		return nil
 	}
-
-	typ := strings.ToLower(string(o.Type))
-	switch Type(typ) {
-	case DefaultKMS, SoftKMS: // Go crypto based kms.
-	case CloudKMS, AmazonKMS, AzureKMS: // Cloud based kms.
-	case YubiKey, PKCS11, TPMKMS: // Hardware based kms.
-	case SSHAgentKMS, CAPIKMS: // Others
-	default:
-		return fmt.Errorf("unsupported kms type %s", o.Type)
-	}
-
-	return nil
+	return o.Type.Validate()
 }
 
 // GetType returns the type in the type property or the one present in the URI.
@@ -175,11 +204,7 @@ func (o *Options) GetType() (Type, error) {
 		return o.Type, nil
 	}
 	if o.URI != "" {
-		u, err := uri.Parse(o.URI)
-		if err != nil {
-			return DefaultKMS, err
-		}
-		return Type(strings.ToLower(u.Scheme)), nil
+		return TypeOf(o.URI)
 	}
 	return SoftKMS, nil
 }
diff --git a/kms/apiv1/options_test.go b/kms/apiv1/options_test.go
index ebcb6db8..d1f1aede 100644
--- a/kms/apiv1/options_test.go
+++ b/kms/apiv1/options_test.go
@@ -1,9 +1,32 @@
 package apiv1
 
 import (
+	"context"
+	"crypto"
+	"os"
 	"testing"
 )
 
+type fakeKM struct{}
+
+func (f *fakeKM) GetPublicKey(req *GetPublicKeyRequest) (crypto.PublicKey, error) {
+	return nil, NotImplementedError{}
+}
+func (f *fakeKM) CreateKey(req *CreateKeyRequest) (*CreateKeyResponse, error) {
+	return nil, NotImplementedError{}
+}
+func (f *fakeKM) CreateSigner(req *CreateSignerRequest) (crypto.Signer, error) {
+	return nil, NotImplementedError{}
+}
+func (f *fakeKM) Close() error { return NotImplementedError{} }
+
+func TestMain(m *testing.M) {
+	Register(Type("fake"), func(ctx context.Context, opts Options) (KeyManager, error) {
+		return &fakeKM{}, nil
+	})
+	os.Exit(m.Run())
+}
+
 func TestOptions_Validate(t *testing.T) {
 	tests := []struct {
 		name    string
@@ -115,3 +138,41 @@ func TestErrAlreadyExists_Error(t *testing.T) {
 		})
 	}
 }
+
+func TestTypeOf(t *testing.T) {
+	type args struct {
+		rawuri string
+	}
+	tests := []struct {
+		name    string
+		args    args
+		want    Type
+		wantErr bool
+	}{
+		{"ok softkms", args{"softkms:foo=bar"}, SoftKMS, false},
+		{"ok cloudkms", args{"CLOUDKMS:"}, CloudKMS, false},
+		{"ok amazonkms", args{"awskms:foo=bar"}, AmazonKMS, false},
+		{"ok pkcs11", args{"PKCS11:foo=bar"}, PKCS11, false},
+		{"ok yubikey", args{"yubikey:foo=bar"}, YubiKey, false},
+		{"ok sshagentkms", args{"sshagentkms:"}, SSHAgentKMS, false},
+		{"ok azurekms", args{"azurekms:foo=bar"}, AzureKMS, false},
+		{"ok capi", args{"CAPI:foo-bar"}, CAPIKMS, false},
+		{"ok tpmkms", args{"tpmkms:"}, TPMKMS, false},
+		{"ok registered", args{"FAKE:"}, Type("fake"), false},
+		{"fail empty", args{""}, DefaultKMS, true},
+		{"fail parse", args{"softkms"}, DefaultKMS, true},
+		{"fail kms", args{"foobar:foo=bar"}, DefaultKMS, true},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got, err := TypeOf(tt.args.rawuri)
+			if (err != nil) != tt.wantErr {
+				t.Errorf("TypeOf() error = %v, wantErr %v", err, tt.wantErr)
+				return
+			}
+			if got != tt.want {
+				t.Errorf("TypeOf() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
diff --git a/kms/apiv1/registry.go b/kms/apiv1/registry.go
index 5a8cf4db..51811499 100644
--- a/kms/apiv1/registry.go
+++ b/kms/apiv1/registry.go
@@ -13,12 +13,12 @@ type KeyManagerNewFunc func(ctx context.Context, opts Options) (KeyManager, erro
 
 // Register adds to the registry a method to create a KeyManager of type t.
 func Register(t Type, fn KeyManagerNewFunc) {
-	registry.Store(t, fn)
+	registry.Store(t.normalize(), fn)
 }
 
 // LoadKeyManagerNewFunc returns the function initialize a KayManager.
 func LoadKeyManagerNewFunc(t Type) (KeyManagerNewFunc, bool) {
-	v, ok := registry.Load(t)
+	v, ok := registry.Load(t.normalize())
 	if !ok {
 		return nil, false
 	}
diff --git a/kms/kms.go b/kms/kms.go
index e06fbdec..c5ad7042 100644
--- a/kms/kms.go
+++ b/kms/kms.go
@@ -32,6 +32,9 @@ type Options = apiv1.Options
 // Type represents the KMS type used.
 type Type = apiv1.Type
 
+// TypeOf returns the KMS type of the given uri.
+var TypeOf = apiv1.TypeOf
+
 // Default is the implementation of the default KMS.
 var Default = &softkms.SoftKMS{}