diff --git a/zaqar/conf/transport.py b/zaqar/conf/transport.py
index 7224f7232..cf00d87f9 100644
--- a/zaqar/conf/transport.py
+++ b/zaqar/conf/transport.py
@@ -138,6 +138,7 @@ message_encryption_algorithms = cfg.StrOpt(
 
 message_encryption_key = cfg.StrOpt(
     'message_encryption_key', default='AES256',
+    secret=True,
     help='Defines the encryption key of algorithms.')