diff --git a/src/security/key-chain.hpp b/src/security/key-chain.hpp
index 043f437..2b6da41 100644
--- a/src/security/key-chain.hpp
+++ b/src/security/key-chain.hpp
@@ -63,6 +63,7 @@
   KeyChain();
 
   template<class KeyChainTraits>
+  explicit
   KeyChain(KeyChainTraits traits);
 
   KeyChain(const std::string& pibName,