diff --git a/plugin.go b/plugin.go
index 40bcce8..6be2781 100644
--- a/plugin.go
+++ b/plugin.go
@@ -161,6 +161,10 @@ func (p *Plugin) Exec() error {
 		return errors.New("missing ssh config (Host, Username)")
 	}
 
+	if len(p.Config.Password) != 0 || len(p.Config.Key) != 0 {
+		return errors.New("can't set password and key at the same time")
+	}
+
 	if len(p.Config.Source) == 0 || len(p.Config.Target) == 0 {
 		return errors.New("missing source or target config")
 	}
diff --git a/plugin_test.go b/plugin_test.go
index 036572c..2218116 100644
--- a/plugin_test.go
+++ b/plugin_test.go
@@ -47,6 +47,23 @@ func TestMissingSourceConfig(t *testing.T) {
 	assert.NotNil(t, err)
 }
 
+func TestSetPasswordAndKey(t *testing.T) {
+	plugin := Plugin{
+		Config: Config{
+			Host:     []string{"example.com"},
+			Username: "ubuntu",
+			Port:     "443",
+			Password: "1234",
+			Key:      "test",
+		},
+	}
+
+	err := plugin.Exec()
+
+	assert.NotNil(t, err)
+	assert.Equal(t, "can't set password and key at the same time", err.Error())
+}
+
 func TestTrimElement(t *testing.T) {
 	var input, result []string