diff --git a/marshal.go b/marshal.go
index 38d7a46..5738615 100644
--- a/marshal.go
+++ b/marshal.go
@@ -169,6 +169,10 @@ func init() {
 
 func encRegister(e interface{}) (err error) {
 	t := reflect.TypeOf(e)
+	if t == nil {
+		return errors.New("ssob: Invalid type")
+	}
+
 	switch t.Kind() {
 	case reflect.Invalid:
 		return errors.New("ssob: Invalid type")
diff --git a/unmarshal.go b/unmarshal.go
index 7737cfd..dc44635 100644
--- a/unmarshal.go
+++ b/unmarshal.go
@@ -203,6 +203,10 @@ func init() {
 
 func decRegister(e interface{}) (err error) {
 	t := reflect.TypeOf(e)
+	if t == nil {
+		return errors.New("ssob: Invalid type")
+	}
+
 	switch t.Kind() {
 	case reflect.Invalid:
 		return errors.New("ssob: Invalid type")