diff --git a/src/security/conf/key-locator-checker.hpp b/src/security/conf/key-locator-checker.hpp
index 52cf888..ff9e5fc 100644
--- a/src/security/conf/key-locator-checker.hpp
+++ b/src/security/conf/key-locator-checker.hpp
@@ -148,6 +148,7 @@
 class RegexKeyLocatorNameChecker : public KeyLocatorChecker
 {
 public:
+  explicit
   RegexKeyLocatorNameChecker(const Regex& regex)
     : m_regex(regex)
   {