diff --git a/opcua2mqtt/MqttBase.py b/opcua2mqtt/MqttBase.py
index 6033846..8649b68 100644
--- a/opcua2mqtt/MqttBase.py
+++ b/opcua2mqtt/MqttBase.py
@@ -44,6 +44,14 @@ class AbstractMqttPublisher(threading.Thread):
                 tls_version=ssl.PROTOCOL_TLSv1_2, 
                 ciphers=None # this does not mean "no cipher" but it means "default ciphers"
             )
+        elif ("ca" in self.config):
+            self.client.tls_set(
+                keyfile=self.config["key"],
+                cert_reqs=ssl.CERT_REQUIRED,
+                tls_version=ssl.PROTOCOL_TLSv1_2, 
+                ciphers=None # this does not mean "no cipher" but it means "default ciphers"
+            )
+
 
         self.client.connect(self.config["broker"], int(self.config["port"]))
         self.client.loop_start()