diff --git a/src/security/conf/rule.hpp b/src/security/conf/rule.hpp
index 6ed5808..31d81f7 100644
--- a/src/security/conf/rule.hpp
+++ b/src/security/conf/rule.hpp
@@ -36,6 +36,7 @@
 class Rule
 {
 public:
+  explicit
   Rule(const std::string& id)
     : m_id(id)
   {