diff --git a/src/security/pib.hpp b/src/security/pib.hpp
index fd8d7cb..b307c83 100644
--- a/src/security/pib.hpp
+++ b/src/security/pib.hpp
@@ -25,10 +25,9 @@
 #include "identity-container.hpp"
 
 namespace ndn {
-class KeyChain;
-
 namespace security {
 
+class KeyChain;
 class PibImpl;
 
 /**